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<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedPeriodStartLabel" xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedPeriodStartLabel"/>
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/netLabel" xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/net-2009-12-16.xsd#netLabel"/>
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  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedTerseLabel"/>
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  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedLabel"/>
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedTotalLabel"/>
  <link:labelLink xlink:role="http://www.xbrl.org/2003/role/link" xlink:type="extended">
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearThree_019dbc7a-b287-7e34-b772-5e2faff9fae4_terseLabel_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2027</link:label>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearThree_label_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Finance Costs, Future Amortization Expense Year Three</link:label>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearThree_documentation_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearThree" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of amortization of deferred financing fees expected to be recognized during year three of the five succeeding fiscal years.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DeferredFinanceCostsFutureAmortizationExpenseYearThree" xlink:href="opi-20251231.xsd#opi_DeferredFinanceCostsFutureAmortizationExpenseYearThree"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DeferredFinanceCostsFutureAmortizationExpenseYearThree" xlink:to="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearThree" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A2650SeniorUnsecuredNotesMember_019dbcaa-f6fe-77d3-94a2-12cf0a0f27db_terseLabel_en-US" xlink:label="lab_opi_A2650SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior unsecured notes, 2.650% interest rate, due in 2026</link:label>
    <link:label id="lab_opi_A2650SeniorUnsecuredNotesMember_019dbc7a-b1cb-7318-be3a-c8902a5792c5_verboseLabel_en-US" xlink:label="lab_opi_A2650SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Existing 2.400% 2027 Notes</link:label>
    <link:label id="lab_opi_A2650SeniorUnsecuredNotesMember_label_en-US" xlink:label="lab_opi_A2650SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2.650% Senior Unsecured Notes [Member]</link:label>
    <link:label id="lab_opi_A2650SeniorUnsecuredNotesMember_documentation_en-US" xlink:label="lab_opi_A2650SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2.650% Senior Unsecured Notes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A2650SeniorUnsecuredNotesMember" xlink:href="opi-20251231.xsd#opi_A2650SeniorUnsecuredNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A2650SeniorUnsecuredNotesMember" xlink:to="lab_opi_A2650SeniorUnsecuredNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A1775WiehleAvenueRestonVAMember_019dbc7a-b287-7560-8725-919f9bf897b0_terseLabel_en-US" xlink:label="lab_opi_A1775WiehleAvenueRestonVAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">1775 Wiehle Avenue, Reston, VA</link:label>
    <link:label id="lab_opi_A1775WiehleAvenueRestonVAMember_label_en-US" xlink:label="lab_opi_A1775WiehleAvenueRestonVAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">1775 Wiehle Avenue, Reston, VA [Member]</link:label>
    <link:label id="lab_opi_A1775WiehleAvenueRestonVAMember_documentation_en-US" xlink:label="lab_opi_A1775WiehleAvenueRestonVAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">1775 Wiehle Avenue [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A1775WiehleAvenueRestonVAMember" xlink:href="opi-20251231.xsd#opi_A1775WiehleAvenueRestonVAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A1775WiehleAvenueRestonVAMember" xlink:to="lab_opi_A1775WiehleAvenueRestonVAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageMarketCapitalizationExceedingSpecifiedAmount_019dbc7a-b287-7a0b-84b9-93a5d7a54572_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageMarketCapitalizationExceedingSpecifiedAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Management fee payable as percentage of average market capitalization exceeding specified amount</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageMarketCapitalizationExceedingSpecifiedAmount_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageMarketCapitalizationExceedingSpecifiedAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction Base Management Fee Payable as Percentage of Average Market Capitalization Exceeding Specified Amount</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageMarketCapitalizationExceedingSpecifiedAmount_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageMarketCapitalizationExceedingSpecifiedAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the base management fee payable as a percentage of average market capitalization exceeding specified amount.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageMarketCapitalizationExceedingSpecifiedAmount" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageMarketCapitalizationExceedingSpecifiedAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageMarketCapitalizationExceedingSpecifiedAmount" xlink:to="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageMarketCapitalizationExceedingSpecifiedAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_019dbc7a-b286-7a44-bd63-ebbfac84e345_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Less: accumulated amortization</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Accumulated Amortization</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearThree_019dbc7a-b287-7b4b-bb02-f3ca929cae0e_terseLabel_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2028</link:label>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearThree_label_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Costs, Leasing Future Amortization Expense Year Three</link:label>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearThree_documentation_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearThree" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of amortization of deferred leasing costs expected to be recognized during year three of the five succeeding fiscal years.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DeferredCostsLeasingFutureAmortizationExpenseYearThree" xlink:href="opi-20251231.xsd#opi_DeferredCostsLeasingFutureAmortizationExpenseYearThree"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DeferredCostsLeasingFutureAmortizationExpenseYearThree" xlink:to="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearThree" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A1211ConnecticutAvenueNWWashingtonDCMember_019dbc7a-b287-7213-98ca-3253f0c739cd_terseLabel_en-US" xlink:label="lab_opi_A1211ConnecticutAvenueNWWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">1211 Connecticut Avenue, NW, Washington DC</link:label>
    <link:label id="lab_opi_A1211ConnecticutAvenueNWWashingtonDCMember_label_en-US" xlink:label="lab_opi_A1211ConnecticutAvenueNWWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">1211 Connecticut Avenue, NW, Washington DC [Member]</link:label>
    <link:label id="lab_opi_A1211ConnecticutAvenueNWWashingtonDCMember_documentation_en-US" xlink:label="lab_opi_A1211ConnecticutAvenueNWWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">1211 Connecticut Avenue, NW, Washington DC [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A1211ConnecticutAvenueNWWashingtonDCMember" xlink:href="opi-20251231.xsd#opi_A1211ConnecticutAvenueNWWashingtonDCMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A1211ConnecticutAvenueNWWashingtonDCMember" xlink:to="lab_opi_A1211ConnecticutAvenueNWWashingtonDCMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AwardTmgPredtrmndFlag_terseLabel_en-US" xlink:label="lab_ecd_AwardTmgPredtrmndFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Award Timing Predetermined</link:label>
    <link:label id="lab_ecd_AwardTmgPredtrmndFlag_label_en-US" xlink:label="lab_ecd_AwardTmgPredtrmndFlag" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Award Timing Predetermined [Flag]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AwardTmgPredtrmndFlag" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AwardTmgPredtrmndFlag"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AwardTmgPredtrmndFlag" xlink:to="lab_ecd_AwardTmgPredtrmndFlag" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityFileNumber_019dbc7a-b286-71e4-92f7-18f0c920301d_terseLabel_en-US" xlink:label="lab_dei_EntityFileNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity File Number</link:label>
    <link:label id="lab_dei_EntityFileNumber_label_en-US" xlink:label="lab_dei_EntityFileNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity File Number</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityFileNumber"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityFileNumber" xlink:to="lab_dei_EntityFileNumber" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AdditionalPaidInCapitalMember_019dbc7a-b287-714f-8c3f-ecbca28879ad_terseLabel_en-US" xlink:label="lab_us-gaap_AdditionalPaidInCapitalMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Additional Paid In Capital</link:label>
    <link:label id="lab_us-gaap_AdditionalPaidInCapitalMember_label_en-US" xlink:label="lab_us-gaap_AdditionalPaidInCapitalMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Additional Paid-in Capital [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdditionalPaidInCapitalMember" xlink:to="lab_us-gaap_AdditionalPaidInCapitalMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A2115ONelDriveSanJoseCAMember_019dbc7a-b287-7fc3-9f8e-fdc7c10949b5_terseLabel_en-US" xlink:label="lab_opi_A2115ONelDriveSanJoseCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2115 O'Nel Drive, San Jose, CA</link:label>
    <link:label id="lab_opi_A2115ONelDriveSanJoseCAMember_label_en-US" xlink:label="lab_opi_A2115ONelDriveSanJoseCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2115 O'Nel Drive, San Jose, CA [Member]</link:label>
    <link:label id="lab_opi_A2115ONelDriveSanJoseCAMember_documentation_en-US" xlink:label="lab_opi_A2115ONelDriveSanJoseCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2115 O'Nel Drive, San Jose, CA [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A2115ONelDriveSanJoseCAMember" xlink:href="opi-20251231.xsd#opi_A2115ONelDriveSanJoseCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A2115ONelDriveSanJoseCAMember" xlink:to="lab_opi_A2115ONelDriveSanJoseCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTen_019dbc7a-b286-7ec0-b5f3-f38d2ed14070_terseLabel_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTen" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2035</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTen_label_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTen" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right Exercisable In Year Ten</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTen_documentation_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTen" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right Exercisable In Year Ten</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTen" xlink:href="opi-20251231.xsd#opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTen"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTen" xlink:to="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTen" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionNumberOfBusinessDaysPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForConvenienceByRelatedParty_019dbc7a-b287-747e-8834-c33c7f48832d_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionNumberOfBusinessDaysPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForConvenienceByRelatedParty" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Written notice for convenience</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionNumberOfBusinessDaysPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForConvenienceByRelatedParty_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionNumberOfBusinessDaysPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForConvenienceByRelatedParty" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction Number Of Business Days Prior Written Notice For Termination Of Property Management Agreement For Convenience By Related Party</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionNumberOfBusinessDaysPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForConvenienceByRelatedParty_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionNumberOfBusinessDaysPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForConvenienceByRelatedParty" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of business days notice for termination of property management agreement by the related party for convenience.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionNumberOfBusinessDaysPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForConvenienceByRelatedParty" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionNumberOfBusinessDaysPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForConvenienceByRelatedParty"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionNumberOfBusinessDaysPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForConvenienceByRelatedParty" xlink:to="lab_opi_RelatedPartyTransactionNumberOfBusinessDaysPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForConvenienceByRelatedParty" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_TabularListTableTextBlock_terseLabel_en-US" xlink:label="lab_ecd_TabularListTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tabular List, Table</link:label>
    <link:label id="lab_ecd_TabularListTableTextBlock_label_en-US" xlink:label="lab_ecd_TabularListTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tabular List [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_TabularListTableTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_TabularListTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_TabularListTableTextBlock" xlink:to="lab_ecd_TabularListTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StraightLineRentAdjustments_019dbc7a-b286-774a-a9b8-1ffb51e907c6_terseLabel_en-US" xlink:label="lab_us-gaap_StraightLineRentAdjustments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Straight line rent adjustments</link:label>
    <link:label id="lab_us-gaap_StraightLineRentAdjustments_label_en-US" xlink:label="lab_us-gaap_StraightLineRentAdjustments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Straight Line Rent Adjustments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StraightLineRentAdjustments" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StraightLineRentAdjustments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StraightLineRentAdjustments" xlink:to="lab_us-gaap_StraightLineRentAdjustments" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfRelatedPartyTransactionsTableTextBlock_019dbc7a-b287-7335-bc3f-87dff3507b2d_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfRelatedPartyTransactionsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Related Party Transactions</link:label>
    <link:label id="lab_us-gaap_ScheduleOfRelatedPartyTransactionsTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfRelatedPartyTransactionsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Related Party Transactions [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfRelatedPartyTransactionsTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredCostsLeasingNet_019dbc7a-b287-7b58-987f-d05e6ad68f90_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredCostsLeasingNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred leasing costs, net</link:label>
    <link:label id="lab_us-gaap_DeferredCostsLeasingNet_label_en-US" xlink:label="lab_us-gaap_DeferredCostsLeasingNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Costs, Leasing, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCostsLeasingNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredCostsLeasingNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredCostsLeasingNet" xlink:to="lab_us-gaap_DeferredCostsLeasingNet" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DebtInstrumentUpfrontFeePercentageCashCommitment_019dd61a-f4db-74c2-95d5-baaf9a5ea811_terseLabel_en-US" xlink:label="lab_opi_DebtInstrumentUpfrontFeePercentageCashCommitment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash percentage of commitments as an upfront fee</link:label>
    <link:label id="lab_opi_DebtInstrumentUpfrontFeePercentageCashCommitment_label_en-US" xlink:label="lab_opi_DebtInstrumentUpfrontFeePercentageCashCommitment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Upfront Fee Percentage, Cash Commitment</link:label>
    <link:label id="lab_opi_DebtInstrumentUpfrontFeePercentageCashCommitment_documentation_en-US" xlink:label="lab_opi_DebtInstrumentUpfrontFeePercentageCashCommitment" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Upfront Fee Percentage, Lender Commitments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DebtInstrumentUpfrontFeePercentageCashCommitment" xlink:href="opi-20251231.xsd#opi_DebtInstrumentUpfrontFeePercentageCashCommitment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DebtInstrumentUpfrontFeePercentageCashCommitment" xlink:to="lab_opi_DebtInstrumentUpfrontFeePercentageCashCommitment" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SecuredOvernightFinancingRateSofrMember_019dd62b-47d8-7694-9f3b-84775687de08_terseLabel_en-US" xlink:label="lab_us-gaap_SecuredOvernightFinancingRateSofrMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">SOFR</link:label>
    <link:label id="lab_us-gaap_SecuredOvernightFinancingRateSofrMember_label_en-US" xlink:label="lab_us-gaap_SecuredOvernightFinancingRateSofrMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Secured Overnight Financing Rate (SOFR) [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredOvernightFinancingRateSofrMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SecuredOvernightFinancingRateSofrMember" xlink:to="lab_us-gaap_SecuredOvernightFinancingRateSofrMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueByBalanceSheetGroupingTextBlock_019dbc7a-b30c-7121-aace-72c2ee17967f_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueByBalanceSheetGroupingTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Fair Value and Carrying Value of Financial Instruments</link:label>
    <link:label id="lab_us-gaap_FairValueByBalanceSheetGroupingTextBlock_label_en-US" xlink:label="lab_us-gaap_FairValueByBalanceSheetGroupingTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, by Balance Sheet Grouping [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByBalanceSheetGroupingTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTextBlock" xlink:to="lab_us-gaap_FairValueByBalanceSheetGroupingTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueByMeasurementBasisAxis_019dbc7a-b286-7712-b869-fcb3bc934802_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueByMeasurementBasisAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Measurement Basis [Axis]</link:label>
    <link:label id="lab_us-gaap_FairValueByMeasurementBasisAxis_label_en-US" xlink:label="lab_us-gaap_FairValueByMeasurementBasisAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Measurement Basis [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis" xlink:to="lab_us-gaap_FairValueByMeasurementBasisAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AdjToCompAxis_terseLabel_en-US" xlink:label="lab_ecd_AdjToCompAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Adjustment to Compensation:</link:label>
    <link:label id="lab_ecd_AdjToCompAxis_label_en-US" xlink:label="lab_ecd_AdjToCompAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Adjustment to Compensation [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AdjToCompAxis" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AdjToCompAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AdjToCompAxis" xlink:to="lab_ecd_AdjToCompAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RelatedPartyTransactionsDisclosureTextBlock_019dbc7a-b286-7efb-8917-f04a1401afeb_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Related Person Transactions</link:label>
    <link:label id="lab_us-gaap_RelatedPartyTransactionsDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transactions Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionsDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyTransactionsDisclosureTextBlock" xlink:to="lab_us-gaap_RelatedPartyTransactionsDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_NamedExecutiveOfficersFnTextBlock_terseLabel_en-US" xlink:label="lab_ecd_NamedExecutiveOfficersFnTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Named Executive Officers, Footnote</link:label>
    <link:label id="lab_ecd_NamedExecutiveOfficersFnTextBlock_label_en-US" xlink:label="lab_ecd_NamedExecutiveOfficersFnTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Named Executive Officers, Footnote [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_NamedExecutiveOfficersFnTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_NamedExecutiveOfficersFnTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_NamedExecutiveOfficersFnTextBlock" xlink:to="lab_ecd_NamedExecutiveOfficersFnTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements_019dbc7a-b287-7c2b-aad0-09ee08907a27_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Buildings and Equipment</link:label>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements_label_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Building and Improvements, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements" xlink:to="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SegmentContinuingOperationsMember_019dbc7a-b1cb-7a2a-8751-a8abe4f53e01_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentContinuingOperationsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Continuing Operations</link:label>
    <link:label id="lab_us-gaap_SegmentContinuingOperationsMember_label_en-US" xlink:label="lab_us-gaap_SegmentContinuingOperationsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Continuing Operations [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentContinuingOperationsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentContinuingOperationsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentContinuingOperationsMember" xlink:to="lab_us-gaap_SegmentContinuingOperationsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AreaOfRealEstateProperty_019dbc7a-b286-7fb6-b7df-e03a32a2b262_verboseLabel_en-US" xlink:label="lab_us-gaap_AreaOfRealEstateProperty" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Rentable area of properties (in square feet)</link:label>
    <link:label id="lab_us-gaap_AreaOfRealEstateProperty_019dbc7a-b286-7d71-809f-571f8c279b0e_netLabel_en-US" xlink:label="lab_us-gaap_AreaOfRealEstateProperty" xlink:role="http://www.xbrl.org/2009/role/netLabel" xlink:type="resource" xml:lang="en-US">Area of properties (in square feet)</link:label>
    <link:label id="lab_us-gaap_AreaOfRealEstateProperty_019dbc7a-b286-7b8a-990a-c23cbce5cf5d_terseLabel_en-US" xlink:label="lab_us-gaap_AreaOfRealEstateProperty" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rentable Square Feet (in square feet)</link:label>
    <link:label id="lab_us-gaap_AreaOfRealEstateProperty_label_en-US" xlink:label="lab_us-gaap_AreaOfRealEstateProperty" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Area of Real Estate Property</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AreaOfRealEstateProperty" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AreaOfRealEstateProperty"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AreaOfRealEstateProperty" xlink:to="lab_us-gaap_AreaOfRealEstateProperty" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_EnterchangeAtMeadowvilleChesterVAMember_019dbc7a-b286-769b-9e54-681e30b48ffb_terseLabel_en-US" xlink:label="lab_opi_EnterchangeAtMeadowvilleChesterVAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Enterchange At Meadowville, Chester, VA</link:label>
    <link:label id="lab_opi_EnterchangeAtMeadowvilleChesterVAMember_label_en-US" xlink:label="lab_opi_EnterchangeAtMeadowvilleChesterVAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Enterchange At Meadowville, Chester, VA [Member]</link:label>
    <link:label id="lab_opi_EnterchangeAtMeadowvilleChesterVAMember_documentation_en-US" xlink:label="lab_opi_EnterchangeAtMeadowvilleChesterVAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Enterchange At Meadowville, Chester, VA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_EnterchangeAtMeadowvilleChesterVAMember" xlink:href="opi-20251231.xsd#opi_EnterchangeAtMeadowvilleChesterVAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_EnterchangeAtMeadowvilleChesterVAMember" xlink:to="lab_opi_EnterchangeAtMeadowvilleChesterVAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AdjToCompAmt_terseLabel_en-US" xlink:label="lab_ecd_AdjToCompAmt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Adjustment to Compensation, Amount</link:label>
    <link:label id="lab_ecd_AdjToCompAmt_label_en-US" xlink:label="lab_ecd_AdjToCompAmt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Adjustment to Compensation Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AdjToCompAmt" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AdjToCompAmt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AdjToCompAmt" xlink:to="lab_ecd_AdjToCompAmt" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ConcentrationRiskPercentage1_019dbc7a-b1cb-7efb-bd79-7a5edb3fa589_terseLabel_en-US" xlink:label="lab_us-gaap_ConcentrationRiskPercentage1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Concentration risk, percentage</link:label>
    <link:label id="lab_us-gaap_ConcentrationRiskPercentage1_label_en-US" xlink:label="lab_us-gaap_ConcentrationRiskPercentage1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConcentrationRiskPercentage1" xlink:to="lab_us-gaap_ConcentrationRiskPercentage1" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_019dbcae-0aba-7547-8b51-0f7f8c1f502d_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Unamortized debt premiums, discounts and issuance costs</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_019dbc7a-b30c-71bc-bb7d-6c5e62e2f0e2_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unamortized debt premiums, discounts and issuance</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:to="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostAbstract_019dbc7a-b286-75fa-b6fe-117eed7510c7_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Initial Cost to Company</link:label>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostAbstract_label_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAndAccumulatedDepreciationInitialCostAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostAbstract" xlink:to="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A3.250SeniorSecuredNotesMember_019dbc7a-b286-763d-bd29-9c1a4ad58575_terseLabel_en-US" xlink:label="lab_opi_A3.250SeniorSecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior secured notes, 3.250% interest rate, due in 2027</link:label>
    <link:label id="lab_opi_A3.250SeniorSecuredNotesMember_label_en-US" xlink:label="lab_opi_A3.250SeniorSecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">3.250% Senior Secured Notes [Member]</link:label>
    <link:label id="lab_opi_A3.250SeniorSecuredNotesMember_documentation_en-US" xlink:label="lab_opi_A3.250SeniorSecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">3.250% Senior Secured Notes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A3.250SeniorSecuredNotesMember" xlink:href="opi-20251231.xsd#opi_A3.250SeniorSecuredNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A3.250SeniorSecuredNotesMember" xlink:to="lab_opi_A3.250SeniorSecuredNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets_019dbc87-d4b3-7a2f-a7d7-d1060342020b_negatedLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Other assets</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Other Operating Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:to="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EmployeeStockOptionMember_terseLabel_en-US" xlink:label="lab_us-gaap_EmployeeStockOptionMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Employee Stock Option</link:label>
    <link:label id="lab_us-gaap_EmployeeStockOptionMember_label_en-US" xlink:label="lab_us-gaap_EmployeeStockOptionMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement, Option [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EmployeeStockOptionMember" xlink:to="lab_us-gaap_EmployeeStockOptionMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SacramentoCAMember_019dbc7a-b286-7e1a-a1ba-da68bd3e2b8f_terseLabel_en-US" xlink:label="lab_opi_SacramentoCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sacramento, CA</link:label>
    <link:label id="lab_opi_SacramentoCAMember_label_en-US" xlink:label="lab_opi_SacramentoCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sacramento, CA [Member]</link:label>
    <link:label id="lab_opi_SacramentoCAMember_documentation_en-US" xlink:label="lab_opi_SacramentoCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sacramento, CA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SacramentoCAMember" xlink:href="opi-20251231.xsd#opi_SacramentoCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SacramentoCAMember" xlink:to="lab_opi_SacramentoCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock_019dbc7a-b287-7d80-8596-eb1649a9b9a6_terseLabel_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash and Cash Equivalents</link:label>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash and Cash Equivalents, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashAndCashEquivalentsPolicyTextBlock" xlink:to="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxesPaid_019dbc8e-3c7e-7dcc-9809-e2bb06e5f89f_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxesPaid" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income taxes paid</link:label>
    <link:label id="lab_us-gaap_IncomeTaxesPaid_label_en-US" xlink:label="lab_us-gaap_IncomeTaxesPaid" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Taxes Paid</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesPaid" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxesPaid"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxesPaid" xlink:to="lab_us-gaap_IncomeTaxesPaid" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DividendsCommonStockCash_019dbc82-55f2-7450-b5c0-4280f27a1453_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DividendsCommonStockCash" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Distributions to common shareholders</link:label>
    <link:label id="lab_us-gaap_DividendsCommonStockCash_label_en-US" xlink:label="lab_us-gaap_DividendsCommonStockCash" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dividends, Common Stock, Cash</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DividendsCommonStockCash"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DividendsCommonStockCash" xlink:to="lab_us-gaap_DividendsCommonStockCash" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockholdersEquity_019dbc7a-b1cb-758c-9f63-4a7ab9814cad_totalLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total shareholders&#8217; equity</link:label>
    <link:label id="lab_us-gaap_StockholdersEquity_019dbc7a-b1cb-71ba-8860-4b102b12bcda_periodStartLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Balance beginning</link:label>
    <link:label id="lab_us-gaap_StockholdersEquity_019dbc7a-b1cb-7d24-90bc-07db439a3b91_periodEndLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Balance ending</link:label>
    <link:label id="lab_us-gaap_StockholdersEquity_label_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity, Attributable to Parent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockholdersEquity" xlink:to="lab_us-gaap_StockholdersEquity" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_InsiderTradingPoliciesProcLineItems_label_en-US" xlink:label="lab_ecd_InsiderTradingPoliciesProcLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Insider Trading Policies and Procedures [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_InsiderTradingPoliciesProcLineItems" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_InsiderTradingPoliciesProcLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_InsiderTradingPoliciesProcLineItems" xlink:to="lab_ecd_InsiderTradingPoliciesProcLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockSharesAuthorized_019dbc7a-b287-7c43-9eb0-a1955b5844cc_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesAuthorized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common shares of beneficial interest, shares authorized (in shares)</link:label>
    <link:label id="lab_us-gaap_CommonStockSharesAuthorized_label_en-US" xlink:label="lab_us-gaap_CommonStockSharesAuthorized" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock, Shares Authorized</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockSharesAuthorized" xlink:to="lab_us-gaap_CommonStockSharesAuthorized" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A6.375SeniorUnsecuredNotesMember_019dbcad-28cb-7e1a-a244-6c42f7bfcfc8_terseLabel_en-US" xlink:label="lab_opi_A6.375SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior unsecured notes, 6.375% interest rate, due in 2050</link:label>
    <link:label id="lab_opi_A6.375SeniorUnsecuredNotesMember_label_en-US" xlink:label="lab_opi_A6.375SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">6.375% Senior Unsecured Notes [Member]</link:label>
    <link:label id="lab_opi_A6.375SeniorUnsecuredNotesMember_documentation_en-US" xlink:label="lab_opi_A6.375SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">6.375% Senior Unsecured Notes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A6.375SeniorUnsecuredNotesMember" xlink:href="opi-20251231.xsd#opi_A6.375SeniorUnsecuredNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A6.375SeniorUnsecuredNotesMember" xlink:to="lab_opi_A6.375SeniorUnsecuredNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionDurationOfTransaction_019dbc7a-b287-71e3-993a-38810d3f6f1f_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionDurationOfTransaction" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Duration of transition services</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionDurationOfTransaction_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionDurationOfTransaction" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Duration Of Transaction</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionDurationOfTransaction_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionDurationOfTransaction" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Duration Of Transaction</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionDurationOfTransaction" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionDurationOfTransaction"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionDurationOfTransaction" xlink:to="lab_opi_RelatedPartyTransactionDurationOfTransaction" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesNewIssues_019dbc7a-b287-7407-b5ae-278b2541ed11_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Issuance of common shares (in shares)</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesNewIssues_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Issued During Period, Shares, New Issues</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:to="lab_us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_NumberOfEmployees_019dbc7a-b1cb-7e1c-8571-5f3efa9ddc9b_terseLabel_en-US" xlink:label="lab_opi_NumberOfEmployees" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of employees</link:label>
    <link:label id="lab_opi_NumberOfEmployees_label_en-US" xlink:label="lab_opi_NumberOfEmployees" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number Of Employees</link:label>
    <link:label id="lab_opi_NumberOfEmployees_documentation_en-US" xlink:label="lab_opi_NumberOfEmployees" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of employees in the company.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_NumberOfEmployees" xlink:href="opi-20251231.xsd#opi_NumberOfEmployees"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_NumberOfEmployees" xlink:to="lab_opi_NumberOfEmployees" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A4201PattersonAvenueBaltimoreMDMember_019dbc7a-b1cb-7451-8152-0769c38cc3f0_terseLabel_en-US" xlink:label="lab_opi_A4201PattersonAvenueBaltimoreMDMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">4201 Patterson Avenue, Baltimore, MD</link:label>
    <link:label id="lab_opi_A4201PattersonAvenueBaltimoreMDMember_label_en-US" xlink:label="lab_opi_A4201PattersonAvenueBaltimoreMDMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">4201 Patterson Avenue, Baltimore, MD [Member]</link:label>
    <link:label id="lab_opi_A4201PattersonAvenueBaltimoreMDMember_documentation_en-US" xlink:label="lab_opi_A4201PattersonAvenueBaltimoreMDMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">4201 Patterson Avenue, Baltimore, MD</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A4201PattersonAvenueBaltimoreMDMember" xlink:href="opi-20251231.xsd#opi_A4201PattersonAvenueBaltimoreMDMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A4201PattersonAvenueBaltimoreMDMember" xlink:to="lab_opi_A4201PattersonAvenueBaltimoreMDMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019dbc7a-b287-7a9f-ad3b-e7c15c03e5dd_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">LIABILITIES AND SHAREHOLDERS&#8217; EQUITY</link:label>
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_label_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities and Equity [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:to="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A445JanDavisDriveHuntsvilleALMember_019dbc7a-b1cb-75b9-bfe6-001de1fa08d2_terseLabel_en-US" xlink:label="lab_opi_A445JanDavisDriveHuntsvilleALMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">445 Jan Davis Drive, Huntsville, AL</link:label>
    <link:label id="lab_opi_A445JanDavisDriveHuntsvilleALMember_label_en-US" xlink:label="lab_opi_A445JanDavisDriveHuntsvilleALMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">445 Jan Davis Drive, Huntsville, AL [Member]</link:label>
    <link:label id="lab_opi_A445JanDavisDriveHuntsvilleALMember_documentation_en-US" xlink:label="lab_opi_A445JanDavisDriveHuntsvilleALMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">445 Jan Davis Drive, Huntsville, AL [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A445JanDavisDriveHuntsvilleALMember" xlink:href="opi-20251231.xsd#opi_A445JanDavisDriveHuntsvilleALMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A445JanDavisDriveHuntsvilleALMember" xlink:to="lab_opi_A445JanDavisDriveHuntsvilleALMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccountsPayableOtherCurrentAndNoncurrent_019dbc7a-b1cb-7cc3-978b-cd40628e5cbb_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsPayableOtherCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Due to related persons</link:label>
    <link:label id="lab_us-gaap_AccountsPayableOtherCurrentAndNoncurrent_label_en-US" xlink:label="lab_us-gaap_AccountsPayableOtherCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Payable, Other</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableOtherCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsPayableOtherCurrentAndNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsPayableOtherCurrentAndNoncurrent" xlink:to="lab_us-gaap_AccountsPayableOtherCurrentAndNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_CoverAbstract_019dbc7a-b1cb-7fc9-ab12-49e2f1743555_terseLabel_en-US" xlink:label="lab_dei_CoverAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cover [Abstract]</link:label>
    <link:label id="lab_dei_CoverAbstract_label_en-US" xlink:label="lab_dei_CoverAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cover [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CoverAbstract" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CoverAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_CoverAbstract" xlink:to="lab_dei_CoverAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PortionAtFairValueFairValueDisclosureMember_019dbc7a-b1cb-7152-bf03-5df29c99b30b_terseLabel_en-US" xlink:label="lab_us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Portion at Fair Value Measurement</link:label>
    <link:label id="lab_us-gaap_PortionAtFairValueFairValueDisclosureMember_label_en-US" xlink:label="lab_us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Portion at Fair Value Measurement [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:to="lab_us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_MaximumMember_019dbc7a-b286-7ce8-adf0-b9a0f0e0b3e0_terseLabel_en-US" xlink:label="lab_srt_MaximumMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Maximum</link:label>
    <link:label id="lab_srt_MaximumMember_label_en-US" xlink:label="lab_srt_MaximumMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Maximum [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_MaximumMember" xlink:to="lab_srt_MaximumMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateInvestmentPropertyNetAbstract_019dbc7a-b1cb-7d75-8bcb-e4b7ffbdae07_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateInvestmentPropertyNetAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real estate properties:</link:label>
    <link:label id="lab_us-gaap_RealEstateInvestmentPropertyNetAbstract_label_en-US" xlink:label="lab_us-gaap_RealEstateInvestmentPropertyNetAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Investment Property, Net [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyNetAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateInvestmentPropertyNetAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateInvestmentPropertyNetAbstract" xlink:to="lab_us-gaap_RealEstateInvestmentPropertyNetAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A299JeffersonRoadParsippanyNJMember_019dbc7a-b287-7607-9f8c-a30c05eb887a_terseLabel_en-US" xlink:label="lab_opi_A299JeffersonRoadParsippanyNJMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">299 Jefferson Road, Parsippany, NJ</link:label>
    <link:label id="lab_opi_A299JeffersonRoadParsippanyNJMember_label_en-US" xlink:label="lab_opi_A299JeffersonRoadParsippanyNJMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">299 Jefferson Road, Parsippany, NJ [Member]</link:label>
    <link:label id="lab_opi_A299JeffersonRoadParsippanyNJMember_documentation_en-US" xlink:label="lab_opi_A299JeffersonRoadParsippanyNJMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">299 Jefferson Road, Parsippany, NJ [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A299JeffersonRoadParsippanyNJMember" xlink:href="opi-20251231.xsd#opi_A299JeffersonRoadParsippanyNJMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A299JeffersonRoadParsippanyNJMember" xlink:to="lab_opi_A299JeffersonRoadParsippanyNJMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsNet_019dbc7a-b287-7150-b6c2-dc615719b68b_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Acquired real estate leases, net</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsNet_019dbc7a-b287-7791-b8b5-b5583d24b661_totalLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Acquired real estate leases, net</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsNet_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_NonPeoNeoAvgTotalCompAmt_terseLabel_en-US" xlink:label="lab_ecd_NonPeoNeoAvgTotalCompAmt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Non-PEO NEO Average Total Compensation Amount</link:label>
    <link:label id="lab_ecd_NonPeoNeoAvgTotalCompAmt_label_en-US" xlink:label="lab_ecd_NonPeoNeoAvgTotalCompAmt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Non-PEO NEO Average Total Compensation Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_NonPeoNeoAvgTotalCompAmt" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_NonPeoNeoAvgTotalCompAmt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_NonPeoNeoAvgTotalCompAmt" xlink:to="lab_ecd_NonPeoNeoAvgTotalCompAmt" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationByPropertyTable_019dbc7a-b287-7b7a-8076-11c4fc6d5b60_terseLabel_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationByPropertyTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, by Property [Table]</link:label>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationByPropertyTable_label_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationByPropertyTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, by Property [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationByPropertyTable" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RealEstateAndAccumulatedDepreciationByPropertyTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationByPropertyTable" xlink:to="lab_srt_RealEstateAndAccumulatedDepreciationByPropertyTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentLineItems_019dbc7a-b287-707b-8917-56ce0804a6c6_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Instrument [Line Items]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentLineItems_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentLineItems" xlink:to="lab_us-gaap_DebtInstrumentLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019dbc7a-b1cb-7acb-a22c-71493e098b1c_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ConcentrationRiskDisclosureTextBlock_019dbc7a-b287-7b38-b947-8b25ed88d45f_terseLabel_en-US" xlink:label="lab_us-gaap_ConcentrationRiskDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Concentration</link:label>
    <link:label id="lab_us-gaap_ConcentrationRiskDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_ConcentrationRiskDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConcentrationRiskDisclosureTextBlock" xlink:to="lab_us-gaap_ConcentrationRiskDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A500CharlesEwingBoulevardEwingNJMember_019dbc7a-b1cb-7a7f-94cb-52089292a265_terseLabel_en-US" xlink:label="lab_opi_A500CharlesEwingBoulevardEwingNJMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">500 Charles Ewing Boulevard, Ewing, NJ</link:label>
    <link:label id="lab_opi_A500CharlesEwingBoulevardEwingNJMember_label_en-US" xlink:label="lab_opi_A500CharlesEwingBoulevardEwingNJMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">500 Charles Ewing Boulevard, Ewing, NJ [Member]</link:label>
    <link:label id="lab_opi_A500CharlesEwingBoulevardEwingNJMember_documentation_en-US" xlink:label="lab_opi_A500CharlesEwingBoulevardEwingNJMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">500 Charles Ewing Boulevard, Ewing, NJ [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A500CharlesEwingBoulevardEwingNJMember" xlink:href="opi-20251231.xsd#opi_A500CharlesEwingBoulevardEwingNJMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A500CharlesEwingBoulevardEwingNJMember" xlink:to="lab_opi_A500CharlesEwingBoulevardEwingNJMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AdjToNonPeoNeoCompFnTextBlock_terseLabel_en-US" xlink:label="lab_ecd_AdjToNonPeoNeoCompFnTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Adjustment to Non-PEO NEO Compensation Footnote</link:label>
    <link:label id="lab_ecd_AdjToNonPeoNeoCompFnTextBlock_label_en-US" xlink:label="lab_ecd_AdjToNonPeoNeoCompFnTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Adjustment to Non-PEO NEO Compensation Footnote [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AdjToNonPeoNeoCompFnTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AdjToNonPeoNeoCompFnTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AdjToNonPeoNeoCompFnTextBlock" xlink:to="lab_ecd_AdjToNonPeoNeoCompFnTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_ForgoneRecoveryDueToDisqualificationOfTaxBenefitsAmt_terseLabel_en-US" xlink:label="lab_ecd_ForgoneRecoveryDueToDisqualificationOfTaxBenefitsAmt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Forgone Recovery due to Disqualification of Tax Benefits, Amount</link:label>
    <link:label id="lab_ecd_ForgoneRecoveryDueToDisqualificationOfTaxBenefitsAmt_label_en-US" xlink:label="lab_ecd_ForgoneRecoveryDueToDisqualificationOfTaxBenefitsAmt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Forgone Recovery due to Disqualification of Tax Benefits, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_ForgoneRecoveryDueToDisqualificationOfTaxBenefitsAmt" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_ForgoneRecoveryDueToDisqualificationOfTaxBenefitsAmt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_ForgoneRecoveryDueToDisqualificationOfTaxBenefitsAmt" xlink:to="lab_ecd_ForgoneRecoveryDueToDisqualificationOfTaxBenefitsAmt" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriod_019dbc7a-b30c-783b-95ff-75e2bd477094_terseLabel_en-US" xlink:label="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Expenditures committed on leases</link:label>
    <link:label id="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriod_label_en-US" xlink:label="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Leases Committed Expenditures on Leases Executed in Period</link:label>
    <link:label id="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriod_documentation_en-US" xlink:label="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriod" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents committed expenditures for operating leases executed during the period.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriod" xlink:href="opi-20251231.xsd#opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriod" xlink:to="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_NonRule10b51ArrTrmntdFlag_terseLabel_en-US" xlink:label="lab_ecd_NonRule10b51ArrTrmntdFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Non-Rule 10b5-1 Arrangement Terminated</link:label>
    <link:label id="lab_ecd_NonRule10b51ArrTrmntdFlag_label_en-US" xlink:label="lab_ecd_NonRule10b51ArrTrmntdFlag" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Non-Rule 10b5-1 Arrangement Terminated [Flag]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_NonRule10b51ArrTrmntdFlag" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_NonRule10b51ArrTrmntdFlag"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_NonRule10b51ArrTrmntdFlag" xlink:to="lab_ecd_NonRule10b51ArrTrmntdFlag" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityShellCompany_019dbc7a-b287-7f15-a1bd-d49598009fa2_terseLabel_en-US" xlink:label="lab_dei_EntityShellCompany" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Shell Company</link:label>
    <link:label id="lab_dei_EntityShellCompany_label_en-US" xlink:label="lab_dei_EntityShellCompany" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Shell Company</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityShellCompany"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityShellCompany" xlink:to="lab_dei_EntityShellCompany" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SaleOfStockCashCommissionPercentage_019dd0dc-686b-73e2-9e80-0ca7bc6e5a09_terseLabel_en-US" xlink:label="lab_opi_SaleOfStockCashCommissionPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash commission percentage</link:label>
    <link:label id="lab_opi_SaleOfStockCashCommissionPercentage_label_en-US" xlink:label="lab_opi_SaleOfStockCashCommissionPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Of Stock, Cash Commission Percentage</link:label>
    <link:label id="lab_opi_SaleOfStockCashCommissionPercentage_documentation_en-US" xlink:label="lab_opi_SaleOfStockCashCommissionPercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Of Stock, Cash Commission Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SaleOfStockCashCommissionPercentage" xlink:href="opi-20251231.xsd#opi_SaleOfStockCashCommissionPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SaleOfStockCashCommissionPercentage" xlink:to="lab_opi_SaleOfStockCashCommissionPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentTable_019dbc7a-b1cb-7c25-93e4-ce19b4ba7cf8_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Long-term Debt Instruments [Table]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentTable_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Long-Term Debt Instruments [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentTable" xlink:to="lab_us-gaap_DebtInstrumentTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReconciliationOfRealEstateAccumulatedDepreciationRollForward_019dbc7a-b1cb-75c5-9b3a-70692f4bb30a_terseLabel_en-US" xlink:label="lab_us-gaap_ReconciliationOfRealEstateAccumulatedDepreciationRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accumulated Depreciation</link:label>
    <link:label id="lab_us-gaap_ReconciliationOfRealEstateAccumulatedDepreciationRollForward_label_en-US" xlink:label="lab_us-gaap_ReconciliationOfRealEstateAccumulatedDepreciationRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationOfRealEstateAccumulatedDepreciationRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReconciliationOfRealEstateAccumulatedDepreciationRollForward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReconciliationOfRealEstateAccumulatedDepreciationRollForward" xlink:to="lab_us-gaap_ReconciliationOfRealEstateAccumulatedDepreciationRollForward" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAggregateBookValueOfRealEstateAssetsOrTransferredAssets_019dbc7a-b1cb-79a9-93cb-0e8d82a81f4d_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAggregateBookValueOfRealEstateAssetsOrTransferredAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage applied on average historical cost of real estate investment properties acquired</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAggregateBookValueOfRealEstateAssetsOrTransferredAssets_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAggregateBookValueOfRealEstateAssetsOrTransferredAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction Percentage Applied on Average Historical Cost of Real Estate Investment Properties Acquired to Calculate Base Management Fee</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAggregateBookValueOfRealEstateAssetsOrTransferredAssets_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAggregateBookValueOfRealEstateAssetsOrTransferredAssets" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the base management fees payable as a percentage of aggregate book value of real estate assets or transferred assets.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAggregateBookValueOfRealEstateAssetsOrTransferredAssets" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAggregateBookValueOfRealEstateAssetsOrTransferredAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAggregateBookValueOfRealEstateAssetsOrTransferredAssets" xlink:to="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAggregateBookValueOfRealEstateAssetsOrTransferredAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementOfStockholdersEquityAbstract_019dbc7a-b286-7836-a20e-65e33d80de26_terseLabel_en-US" xlink:label="lab_us-gaap_StatementOfStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statement of Stockholders' Equity [Abstract]</link:label>
    <link:label id="lab_us-gaap_StatementOfStockholdersEquityAbstract_label_en-US" xlink:label="lab_us-gaap_StatementOfStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Stockholders' Equity [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfStockholdersEquityAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementOfStockholdersEquityAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfStockholdersEquityAbstract" xlink:to="lab_us-gaap_StatementOfStockholdersEquityAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AwardTmgMnpiCnsdrdFlag_terseLabel_en-US" xlink:label="lab_ecd_AwardTmgMnpiCnsdrdFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Award Timing MNPI Considered</link:label>
    <link:label id="lab_ecd_AwardTmgMnpiCnsdrdFlag_label_en-US" xlink:label="lab_ecd_AwardTmgMnpiCnsdrdFlag" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Award Timing MNPI Considered [Flag]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AwardTmgMnpiCnsdrdFlag" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AwardTmgMnpiCnsdrdFlag"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AwardTmgMnpiCnsdrdFlag" xlink:to="lab_ecd_AwardTmgMnpiCnsdrdFlag" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_AtlantaGA2Member_019dbc7a-b30c-7045-810e-d13806621f52_terseLabel_en-US" xlink:label="lab_opi_AtlantaGA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Atlanta, GA</link:label>
    <link:label id="lab_opi_AtlantaGA2Member_label_en-US" xlink:label="lab_opi_AtlantaGA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlanta, GA 2 [Member]</link:label>
    <link:label id="lab_opi_AtlantaGA2Member_documentation_en-US" xlink:label="lab_opi_AtlantaGA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlanta, GA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_AtlantaGA2Member" xlink:href="opi-20251231.xsd#opi_AtlantaGA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_AtlantaGA2Member" xlink:to="lab_opi_AtlantaGA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionLoyaltyFeePercentOfQualifiedRoomRevenues_019dbc7a-b287-7112-8953-bb9a0e7cb6f0_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionLoyaltyFeePercentOfQualifiedRoomRevenues" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loyalty fee, percent of qualified room revenues</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionLoyaltyFeePercentOfQualifiedRoomRevenues_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionLoyaltyFeePercentOfQualifiedRoomRevenues" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Loyalty Fee, Percent Of Qualified Room Revenues</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionLoyaltyFeePercentOfQualifiedRoomRevenues_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionLoyaltyFeePercentOfQualifiedRoomRevenues" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Loyalty Fee, Percent Of Qualified Room Revenues</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionLoyaltyFeePercentOfQualifiedRoomRevenues" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionLoyaltyFeePercentOfQualifiedRoomRevenues"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionLoyaltyFeePercentOfQualifiedRoomRevenues" xlink:to="lab_opi_RelatedPartyTransactionLoyaltyFeePercentOfQualifiedRoomRevenues" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A2300And2400YorkmontRoadCharlotteNCMember_019dbc7a-b1cb-7227-885b-9cc598887d9f_terseLabel_en-US" xlink:label="lab_opi_A2300And2400YorkmontRoadCharlotteNCMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2300 and 2400 Yorkmont Road, Charlotte, NC</link:label>
    <link:label id="lab_opi_A2300And2400YorkmontRoadCharlotteNCMember_label_en-US" xlink:label="lab_opi_A2300And2400YorkmontRoadCharlotteNCMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2300 and 2400 Yorkmont Road, Charlotte, NC [Member]</link:label>
    <link:label id="lab_opi_A2300And2400YorkmontRoadCharlotteNCMember_documentation_en-US" xlink:label="lab_opi_A2300And2400YorkmontRoadCharlotteNCMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2300 and 2400 Yorkmont Road, Charlotte, NC</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A2300And2400YorkmontRoadCharlotteNCMember" xlink:href="opi-20251231.xsd#opi_A2300And2400YorkmontRoadCharlotteNCMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A2300And2400YorkmontRoadCharlotteNCMember" xlink:to="lab_opi_A2300And2400YorkmontRoadCharlotteNCMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtConversionNameDomain_019dbc7a-b287-7f0c-bd5a-4c0d2af505c7_terseLabel_en-US" xlink:label="lab_us-gaap_DebtConversionNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Conversion, Name [Domain]</link:label>
    <link:label id="lab_us-gaap_DebtConversionNameDomain_label_en-US" xlink:label="lab_us-gaap_DebtConversionNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Conversion, Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtConversionNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtConversionNameDomain" xlink:to="lab_us-gaap_DebtConversionNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A7210MortgageNotesPayableMember_019dbcac-d5ce-708d-a11c-e7400c22826a_terseLabel_en-US" xlink:label="lab_opi_A7210MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mortgage note payable, 7.210% interest rate, due in 2033</link:label>
    <link:label id="lab_opi_A7210MortgageNotesPayableMember_label_en-US" xlink:label="lab_opi_A7210MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">7.210% Mortgage Notes Payable [Member]</link:label>
    <link:label id="lab_opi_A7210MortgageNotesPayableMember_documentation_en-US" xlink:label="lab_opi_A7210MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">7.210% Mortgage Notes Payable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A7210MortgageNotesPayableMember" xlink:href="opi-20251231.xsd#opi_A7210MortgageNotesPayableMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A7210MortgageNotesPayableMember" xlink:to="lab_opi_A7210MortgageNotesPayableMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ProceedsFromIssuanceOfSecuredTermLoan_019dbc8d-3d80-7a5f-9192-52e224f138c2_terseLabel_en-US" xlink:label="lab_opi_ProceedsFromIssuanceOfSecuredTermLoan" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Borrowings on secured term loan</link:label>
    <link:label id="lab_opi_ProceedsFromIssuanceOfSecuredTermLoan_label_en-US" xlink:label="lab_opi_ProceedsFromIssuanceOfSecuredTermLoan" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds From Issuance Of Secured Term Loan</link:label>
    <link:label id="lab_opi_ProceedsFromIssuanceOfSecuredTermLoan_documentation_en-US" xlink:label="lab_opi_ProceedsFromIssuanceOfSecuredTermLoan" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Proceeds From Issuance Of Secured Term Loan</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ProceedsFromIssuanceOfSecuredTermLoan" xlink:href="opi-20251231.xsd#opi_ProceedsFromIssuanceOfSecuredTermLoan"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ProceedsFromIssuanceOfSecuredTermLoan" xlink:to="lab_opi_ProceedsFromIssuanceOfSecuredTermLoan" xlink:type="arc" order="1"/>
    <link:label id="lab_stpr_TX_019dbc7a-b1cb-764b-8721-67d6f46c0274_terseLabel_en-US" xlink:label="lab_stpr_TX" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Texas</link:label>
    <link:label id="lab_stpr_TX_label_en-US" xlink:label="lab_stpr_TX" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">TEXAS</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_TX" xlink:href="https://xbrl.sec.gov/stpr/2025/stpr-2025.xsd#stpr_TX"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_stpr_TX" xlink:to="lab_stpr_TX" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentFiscalPeriodFocus_019dbc7a-b1cb-765f-ab02-f3ca2a43698d_terseLabel_en-US" xlink:label="lab_dei_DocumentFiscalPeriodFocus" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Document Fiscal Period Focus</link:label>
    <link:label id="lab_dei_DocumentFiscalPeriodFocus_label_en-US" xlink:label="lab_dei_DocumentFiscalPeriodFocus" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Document Fiscal Period Focus</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentFiscalPeriodFocus" xlink:to="lab_dei_DocumentFiscalPeriodFocus" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateTaxExpense_019dbc7a-b1cb-76d1-9e22-b854197184f9_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateTaxExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real estate taxes</link:label>
    <link:label id="lab_us-gaap_RealEstateTaxExpense_label_en-US" xlink:label="lab_us-gaap_RealEstateTaxExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Tax Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateTaxExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateTaxExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateTaxExpense" xlink:to="lab_us-gaap_RealEstateTaxExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ColoradoSpringsCOMember_019dbc7a-b287-7cbc-9a06-87f03d535578_terseLabel_en-US" xlink:label="lab_opi_ColoradoSpringsCOMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Colorado Springs, CO</link:label>
    <link:label id="lab_opi_ColoradoSpringsCOMember_label_en-US" xlink:label="lab_opi_ColoradoSpringsCOMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Colorado Springs, CO [Member]</link:label>
    <link:label id="lab_opi_ColoradoSpringsCOMember_documentation_en-US" xlink:label="lab_opi_ColoradoSpringsCOMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Colorado Springs, CO</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ColoradoSpringsCOMember" xlink:href="opi-20251231.xsd#opi_ColoradoSpringsCOMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ColoradoSpringsCOMember" xlink:to="lab_opi_ColoradoSpringsCOMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AwardTmgMethodTextBlock_terseLabel_en-US" xlink:label="lab_ecd_AwardTmgMethodTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Award Timing Method</link:label>
    <link:label id="lab_ecd_AwardTmgMethodTextBlock_label_en-US" xlink:label="lab_ecd_AwardTmgMethodTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Award Timing Method [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AwardTmgMethodTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AwardTmgMethodTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AwardTmgMethodTextBlock" xlink:to="lab_ecd_AwardTmgMethodTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AwardTypeAxis_terseLabel_en-US" xlink:label="lab_us-gaap_AwardTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Award Type</link:label>
    <link:label id="lab_us-gaap_AwardTypeAxis_label_en-US" xlink:label="lab_us-gaap_AwardTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Award Type [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AwardTypeAxis" xlink:to="lab_us-gaap_AwardTypeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_AccountingPoliciesTable_019e2c1a-79ea-7183-b2d5-37ec07b169eb_terseLabel_en-US" xlink:label="lab_opi_AccountingPoliciesTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounting Policies [Table]</link:label>
    <link:label id="lab_opi_AccountingPoliciesTable_label_en-US" xlink:label="lab_opi_AccountingPoliciesTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounting Policies [Table]</link:label>
    <link:label id="lab_opi_AccountingPoliciesTable_documentation_en-US" xlink:label="lab_opi_AccountingPoliciesTable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Accounting Policies [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_AccountingPoliciesTable" xlink:href="opi-20251231.xsd#opi_AccountingPoliciesTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_AccountingPoliciesTable" xlink:to="lab_opi_AccountingPoliciesTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInDeferredLeasingFees_019dbc87-ce86-7b4b-ae4d-29e0abe3e4f6_negatedLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInDeferredLeasingFees" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Deferred leasing costs</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInDeferredLeasingFees_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInDeferredLeasingFees" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Deferred Leasing Fees</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredLeasingFees" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInDeferredLeasingFees"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInDeferredLeasingFees" xlink:to="lab_us-gaap_IncreaseDecreaseInDeferredLeasingFees" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_EquityMethodInvesteeNameDomain_019dbc7a-b287-780a-9c3c-cc0c5921fb0b_terseLabel_en-US" xlink:label="lab_srt_EquityMethodInvesteeNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Investment, Name [Domain]</link:label>
    <link:label id="lab_srt_EquityMethodInvesteeNameDomain_label_en-US" xlink:label="lab_srt_EquityMethodInvesteeNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investment, Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_EquityMethodInvesteeNameDomain" xlink:to="lab_srt_EquityMethodInvesteeNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_stpr_VA_019dbc7a-b1cb-7f31-a997-00d3bc0c0fc6_terseLabel_en-US" xlink:label="lab_stpr_VA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Virginia</link:label>
    <link:label id="lab_stpr_VA_label_en-US" xlink:label="lab_stpr_VA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">VIRGINIA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_VA" xlink:href="https://xbrl.sec.gov/stpr/2025/stpr-2025.xsd#stpr_VA"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_stpr_VA" xlink:to="lab_stpr_VA" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityAddressCityOrTown_019dbc7a-b287-7b93-a91b-c227e5121d81_terseLabel_en-US" xlink:label="lab_dei_EntityAddressCityOrTown" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Address, City or Town</link:label>
    <link:label id="lab_dei_EntityAddressCityOrTown_label_en-US" xlink:label="lab_dei_EntityAddressCityOrTown" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Address, City or Town</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressCityOrTown"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressCityOrTown" xlink:to="lab_dei_EntityAddressCityOrTown" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A1224HammondDriveAtlantaGAMember_019dbc7a-b287-7ef3-880b-fe327324b36c_terseLabel_en-US" xlink:label="lab_opi_A1224HammondDriveAtlantaGAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">1224 Hammond Drive, Atlanta GA</link:label>
    <link:label id="lab_opi_A1224HammondDriveAtlantaGAMember_label_en-US" xlink:label="lab_opi_A1224HammondDriveAtlantaGAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">1224 Hammond Drive, Atlanta GA [Member]</link:label>
    <link:label id="lab_opi_A1224HammondDriveAtlantaGAMember_documentation_en-US" xlink:label="lab_opi_A1224HammondDriveAtlantaGAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">1224 Hammond Drive, Atlanta GA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A1224HammondDriveAtlantaGAMember" xlink:href="opi-20251231.xsd#opi_A1224HammondDriveAtlantaGAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A1224HammondDriveAtlantaGAMember" xlink:to="lab_opi_A1224HammondDriveAtlantaGAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_WeightedAverageAnnualInterestRate_019dbc7a-b1cb-768c-96dc-5dec954809b9_terseLabel_en-US" xlink:label="lab_opi_WeightedAverageAnnualInterestRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted average annual interest rate</link:label>
    <link:label id="lab_opi_WeightedAverageAnnualInterestRate_label_en-US" xlink:label="lab_opi_WeightedAverageAnnualInterestRate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Weighted Average Annual Interest Rate</link:label>
    <link:label id="lab_opi_WeightedAverageAnnualInterestRate_documentation_en-US" xlink:label="lab_opi_WeightedAverageAnnualInterestRate" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the calculation of the average interest rate weighted by the amount of long-term debt outstanding by type or by instrument at that time.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_WeightedAverageAnnualInterestRate" xlink:href="opi-20251231.xsd#opi_WeightedAverageAnnualInterestRate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_WeightedAverageAnnualInterestRate" xlink:to="lab_opi_WeightedAverageAnnualInterestRate" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SanJoseCAMember_019dbc7a-b287-773a-91f0-daa454cafc70_terseLabel_en-US" xlink:label="lab_opi_SanJoseCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">San Jose, CA</link:label>
    <link:label id="lab_opi_SanJoseCAMember_label_en-US" xlink:label="lab_opi_SanJoseCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">San Jose, CA [Member]</link:label>
    <link:label id="lab_opi_SanJoseCAMember_documentation_en-US" xlink:label="lab_opi_SanJoseCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">San Jose, CA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SanJoseCAMember" xlink:href="opi-20251231.xsd#opi_SanJoseCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SanJoseCAMember" xlink:to="lab_opi_SanJoseCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_NonPeoNeoAvgCompActuallyPaidAmt_terseLabel_en-US" xlink:label="lab_ecd_NonPeoNeoAvgCompActuallyPaidAmt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Non-PEO NEO Average Compensation Actually Paid Amount</link:label>
    <link:label id="lab_ecd_NonPeoNeoAvgCompActuallyPaidAmt_label_en-US" xlink:label="lab_ecd_NonPeoNeoAvgCompActuallyPaidAmt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Non-PEO NEO Average Compensation Actually Paid Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_NonPeoNeoAvgCompActuallyPaidAmt" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_NonPeoNeoAvgCompActuallyPaidAmt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_NonPeoNeoAvgCompActuallyPaidAmt" xlink:to="lab_ecd_NonPeoNeoAvgCompActuallyPaidAmt" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_OtherGeneralUnsecuredClaimsReceivable_019e184a-9e42-770a-b8b1-ae8d6250ae75_terseLabel_en-US" xlink:label="lab_opi_OtherGeneralUnsecuredClaimsReceivable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash receivable for other general unsecured claims</link:label>
    <link:label id="lab_opi_OtherGeneralUnsecuredClaimsReceivable_label_en-US" xlink:label="lab_opi_OtherGeneralUnsecuredClaimsReceivable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other General Unsecured Claims, Receivable</link:label>
    <link:label id="lab_opi_OtherGeneralUnsecuredClaimsReceivable_documentation_en-US" xlink:label="lab_opi_OtherGeneralUnsecuredClaimsReceivable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Other General Unsecured Claims, Receivable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_OtherGeneralUnsecuredClaimsReceivable" xlink:href="opi-20251231.xsd#opi_OtherGeneralUnsecuredClaimsReceivable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_OtherGeneralUnsecuredClaimsReceivable" xlink:to="lab_opi_OtherGeneralUnsecuredClaimsReceivable" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_AtlantaGAMember_019dbc7a-b1cb-7194-9c3a-3b1579c1e4eb_terseLabel_en-US" xlink:label="lab_opi_AtlantaGAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Atlanta, GA</link:label>
    <link:label id="lab_opi_AtlantaGAMember_label_en-US" xlink:label="lab_opi_AtlantaGAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlanta, GA [Member]</link:label>
    <link:label id="lab_opi_AtlantaGAMember_documentation_en-US" xlink:label="lab_opi_AtlantaGAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlanta, GA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_AtlantaGAMember" xlink:href="opi-20251231.xsd#opi_AtlantaGAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_AtlantaGAMember" xlink:to="lab_opi_AtlantaGAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAccumulatedDepreciationRealEstateSold_019dbc7a-b287-727d-897a-708e619d9b49_negatedLabel_en-US" xlink:label="lab_us-gaap_RealEstateAccumulatedDepreciationRealEstateSold" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Disposals</link:label>
    <link:label id="lab_us-gaap_RealEstateAccumulatedDepreciationRealEstateSold_label_en-US" xlink:label="lab_us-gaap_RealEstateAccumulatedDepreciationRealEstateSold" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation, Investment in Real Estate Sold</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAccumulatedDepreciationRealEstateSold" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAccumulatedDepreciationRealEstateSold"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAccumulatedDepreciationRealEstateSold" xlink:to="lab_us-gaap_RealEstateAccumulatedDepreciationRealEstateSold" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_CompActuallyPaidVsOtherMeasureTextBlock_terseLabel_en-US" xlink:label="lab_ecd_CompActuallyPaidVsOtherMeasureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Compensation Actually Paid vs. Other Measure</link:label>
    <link:label id="lab_ecd_CompActuallyPaidVsOtherMeasureTextBlock_label_en-US" xlink:label="lab_ecd_CompActuallyPaidVsOtherMeasureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Compensation Actually Paid vs. Other Measure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_CompActuallyPaidVsOtherMeasureTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_CompActuallyPaidVsOtherMeasureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_CompActuallyPaidVsOtherMeasureTextBlock" xlink:to="lab_ecd_CompActuallyPaidVsOtherMeasureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A8139MortgageNotesPayableMember_019dbcab-659d-707b-bf1d-ee5267151bb1_terseLabel_en-US" xlink:label="lab_opi_A8139MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mortgage note payable, 8.139% interest rate, due in 2028</link:label>
    <link:label id="lab_opi_A8139MortgageNotesPayableMember_label_en-US" xlink:label="lab_opi_A8139MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">8.139% Mortgage Notes Payable [Member]</link:label>
    <link:label id="lab_opi_A8139MortgageNotesPayableMember_documentation_en-US" xlink:label="lab_opi_A8139MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">8.139% Mortgage Notes Payable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A8139MortgageNotesPayableMember" xlink:href="opi-20251231.xsd#opi_A8139MortgageNotesPayableMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A8139MortgageNotesPayableMember" xlink:to="lab_opi_A8139MortgageNotesPayableMember" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityEmergingGrowthCompany_019dbc7a-b286-7c87-9354-cb1f7ad95119_terseLabel_en-US" xlink:label="lab_dei_EntityEmergingGrowthCompany" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Emerging Growth Company</link:label>
    <link:label id="lab_dei_EntityEmergingGrowthCompany_label_en-US" xlink:label="lab_dei_EntityEmergingGrowthCompany" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Emerging Growth Company</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityEmergingGrowthCompany" xlink:to="lab_dei_EntityEmergingGrowthCompany" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_019dbc7a-b1cb-75f8-9a9d-4fec618f634c_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2028</link:label>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Maturity, Year Three</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ReitManagementAndResearchLLCMember_019dbc7a-b287-78d9-841c-45be4c20d4b0_terseLabel_en-US" xlink:label="lab_opi_ReitManagementAndResearchLLCMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">RMR LLC</link:label>
    <link:label id="lab_opi_ReitManagementAndResearchLLCMember_label_en-US" xlink:label="lab_opi_ReitManagementAndResearchLLCMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reit Management And Research L L C [Member]</link:label>
    <link:label id="lab_opi_ReitManagementAndResearchLLCMember_documentation_en-US" xlink:label="lab_opi_ReitManagementAndResearchLLCMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents details pertaining to Reit Management and Research LLC, or RMR.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ReitManagementAndResearchLLCMember" xlink:href="opi-20251231.xsd#opi_ReitManagementAndResearchLLCMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ReitManagementAndResearchLLCMember" xlink:to="lab_opi_ReitManagementAndResearchLLCMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_ChngInFrValAsOfVstngDtOfPrrYrEqtyAwrdsVstdInCvrdYrMember_terseLabel_en-US" xlink:label="lab_ecd_ChngInFrValAsOfVstngDtOfPrrYrEqtyAwrdsVstdInCvrdYrMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year</link:label>
    <link:label id="lab_ecd_ChngInFrValAsOfVstngDtOfPrrYrEqtyAwrdsVstdInCvrdYrMember_label_en-US" xlink:label="lab_ecd_ChngInFrValAsOfVstngDtOfPrrYrEqtyAwrdsVstdInCvrdYrMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_ChngInFrValAsOfVstngDtOfPrrYrEqtyAwrdsVstdInCvrdYrMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_ChngInFrValAsOfVstngDtOfPrrYrEqtyAwrdsVstdInCvrdYrMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_ChngInFrValAsOfVstngDtOfPrrYrEqtyAwrdsVstdInCvrdYrMember" xlink:to="lab_ecd_ChngInFrValAsOfVstngDtOfPrrYrEqtyAwrdsVstdInCvrdYrMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredFinanceCostsNet_019dbc7a-b1cb-7b3e-b04d-934320979cce_verboseLabel_en-US" xlink:label="lab_us-gaap_DeferredFinanceCostsNet" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Deferred financing fees, net</link:label>
    <link:label id="lab_us-gaap_DeferredFinanceCostsNet_label_en-US" xlink:label="lab_us-gaap_DeferredFinanceCostsNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Issuance Costs, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredFinanceCostsNet" xlink:to="lab_us-gaap_DeferredFinanceCostsNet" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RestrictedCashAndCashEquivalents_019dbc7a-b30c-70f0-8479-826936789373_terseLabel_en-US" xlink:label="lab_us-gaap_RestrictedCashAndCashEquivalents" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Restricted cash</link:label>
    <link:label id="lab_us-gaap_RestrictedCashAndCashEquivalents_label_en-US" xlink:label="lab_us-gaap_RestrictedCashAndCashEquivalents" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Restricted Cash and Cash Equivalent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalents" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedCashAndCashEquivalents"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalents" xlink:to="lab_us-gaap_RestrictedCashAndCashEquivalents" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A4241NE34thStreetKansasCityMOMember_019dbc7a-b1cb-7b27-b873-703f13d1a25e_terseLabel_en-US" xlink:label="lab_opi_A4241NE34thStreetKansasCityMOMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">4241 NE 34th Street, Kansas City, MO</link:label>
    <link:label id="lab_opi_A4241NE34thStreetKansasCityMOMember_label_en-US" xlink:label="lab_opi_A4241NE34thStreetKansasCityMOMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">4241 NE 34th Street, Kansas City, MO [Member]</link:label>
    <link:label id="lab_opi_A4241NE34thStreetKansasCityMOMember_documentation_en-US" xlink:label="lab_opi_A4241NE34thStreetKansasCityMOMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">4241 NE 34th Street, Kansas City, MO</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A4241NE34thStreetKansasCityMOMember" xlink:href="opi-20251231.xsd#opi_A4241NE34thStreetKansasCityMOMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A4241NE34thStreetKansasCityMOMember" xlink:to="lab_opi_A4241NE34thStreetKansasCityMOMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LeasesAcquiredInPlaceMember_019dbc7a-b287-7d7e-95dc-fdaa6f572db1_terseLabel_en-US" xlink:label="lab_us-gaap_LeasesAcquiredInPlaceMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Original Value Lease</link:label>
    <link:label id="lab_us-gaap_LeasesAcquiredInPlaceMember_label_en-US" xlink:label="lab_us-gaap_LeasesAcquiredInPlaceMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Leases, Acquired-in-Place [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAcquiredInPlaceMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LeasesAcquiredInPlaceMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LeasesAcquiredInPlaceMember" xlink:to="lab_us-gaap_LeasesAcquiredInPlaceMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtConversionByUniqueDescriptionAxis_019dbc7a-b286-7b23-b406-61e29afb7587_terseLabel_en-US" xlink:label="lab_us-gaap_DebtConversionByUniqueDescriptionAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Conversion Description [Axis]</link:label>
    <link:label id="lab_us-gaap_DebtConversionByUniqueDescriptionAxis_label_en-US" xlink:label="lab_us-gaap_DebtConversionByUniqueDescriptionAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Conversion Description [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionByUniqueDescriptionAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtConversionByUniqueDescriptionAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtConversionByUniqueDescriptionAxis" xlink:to="lab_us-gaap_DebtConversionByUniqueDescriptionAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockSharesOutstanding_019dbc7a-b287-77ef-b474-7d5c2057b4ca_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common shares of beneficial interest, shares outstanding (in shares)</link:label>
    <link:label id="lab_us-gaap_CommonStockSharesOutstanding_label_en-US" xlink:label="lab_us-gaap_CommonStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock, Shares, Outstanding</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockSharesOutstanding" xlink:to="lab_us-gaap_CommonStockSharesOutstanding" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A131ClaytonStreetMontgomeryALMember_019dbc7a-b287-7505-b74a-3e15e976f46f_terseLabel_en-US" xlink:label="lab_opi_A131ClaytonStreetMontgomeryALMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">131 Clayton Street, Montgomery, AL</link:label>
    <link:label id="lab_opi_A131ClaytonStreetMontgomeryALMember_label_en-US" xlink:label="lab_opi_A131ClaytonStreetMontgomeryALMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">131 Clayton Street, Montgomery, AL [Member]</link:label>
    <link:label id="lab_opi_A131ClaytonStreetMontgomeryALMember_documentation_en-US" xlink:label="lab_opi_A131ClaytonStreetMontgomeryALMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">131 Clayton Street, Montgomery, AL</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A131ClaytonStreetMontgomeryALMember" xlink:href="opi-20251231.xsd#opi_A131ClaytonStreetMontgomeryALMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A131ClaytonStreetMontgomeryALMember" xlink:to="lab_opi_A131ClaytonStreetMontgomeryALMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt_019dbc8d-24dd-7a7c-9d78-fafafd507bf4_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from issuance of senior secured notes</link:label>
    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt_label_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Issuance of Senior Long-Term Debt</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt" xlink:to="lab_us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements_019dbc7a-b286-70e8-9c26-46703e7f9889_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Buildings and Equipment</link:label>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements_label_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost of Building and Improvements</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements" xlink:to="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_DvddsOrOthrErngsPdOnEqtyAwrdsNtOthrwsRflctdInTtlCompForCvrdYrMember_terseLabel_en-US" xlink:label="lab_ecd_DvddsOrOthrErngsPdOnEqtyAwrdsNtOthrwsRflctdInTtlCompForCvrdYrMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year</link:label>
    <link:label id="lab_ecd_DvddsOrOthrErngsPdOnEqtyAwrdsNtOthrwsRflctdInTtlCompForCvrdYrMember_label_en-US" xlink:label="lab_ecd_DvddsOrOthrErngsPdOnEqtyAwrdsNtOthrwsRflctdInTtlCompForCvrdYrMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_DvddsOrOthrErngsPdOnEqtyAwrdsNtOthrwsRflctdInTtlCompForCvrdYrMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_DvddsOrOthrErngsPdOnEqtyAwrdsNtOthrwsRflctdInTtlCompForCvrdYrMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_DvddsOrOthrErngsPdOnEqtyAwrdsNtOthrwsRflctdInTtlCompForCvrdYrMember" xlink:to="lab_ecd_DvddsOrOthrErngsPdOnEqtyAwrdsNtOthrwsRflctdInTtlCompForCvrdYrMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A9.000SeniorSecuredNotesPayableDueInMarch2029Member_019dbc7a-b286-7067-bdd7-dc5d36c63589_terseLabel_en-US" xlink:label="lab_opi_A9.000SeniorSecuredNotesPayableDueInMarch2029Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior secured notes, 9.000% interest rate, due in March 2029</link:label>
    <link:label id="lab_opi_A9.000SeniorSecuredNotesPayableDueInMarch2029Member_label_en-US" xlink:label="lab_opi_A9.000SeniorSecuredNotesPayableDueInMarch2029Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">9.000% Senior Secured Notes Payable, Due In March 2029 [Member]</link:label>
    <link:label id="lab_opi_A9.000SeniorSecuredNotesPayableDueInMarch2029Member_documentation_en-US" xlink:label="lab_opi_A9.000SeniorSecuredNotesPayableDueInMarch2029Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">9.000% Senior Secured Notes Payable, Due In March 2029</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A9.000SeniorSecuredNotesPayableDueInMarch2029Member" xlink:href="opi-20251231.xsd#opi_A9.000SeniorSecuredNotesPayableDueInMarch2029Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A9.000SeniorSecuredNotesPayableDueInMarch2029Member" xlink:to="lab_opi_A9.000SeniorSecuredNotesPayableDueInMarch2029Member" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionLoyaltyFeePercentOfRoomRevenues_019dbc7a-b287-7e2b-95ba-9a6218121e49_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionLoyaltyFeePercentOfRoomRevenues" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loyalty fee, percent of room revenues</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionLoyaltyFeePercentOfRoomRevenues_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionLoyaltyFeePercentOfRoomRevenues" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Loyalty Fee, Percent Of Room Revenues</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionLoyaltyFeePercentOfRoomRevenues_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionLoyaltyFeePercentOfRoomRevenues" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Loyalty Fee, Percent Of Room Revenues</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionLoyaltyFeePercentOfRoomRevenues" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionLoyaltyFeePercentOfRoomRevenues"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionLoyaltyFeePercentOfRoomRevenues" xlink:to="lab_opi_RelatedPartyTransactionLoyaltyFeePercentOfRoomRevenues" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageMinimumThreshold_019dbc7a-b30c-75a3-a706-57e12acee37d_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageMinimumThreshold" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage for limitation and adjustments of incentive management fee payable, minimum total return per share percentage change</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageMinimumThreshold_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageMinimumThreshold" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Percentage For Limitation And Adjustments Of Incentive Management Fee Payable, Percentage Minimum Threshold</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageMinimumThreshold_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageMinimumThreshold" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Percentage For Limitation And Adjustments Of Incentive Management Fee Payable, Percentage Minimum Threshold</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageMinimumThreshold" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageMinimumThreshold"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageMinimumThreshold" xlink:to="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageMinimumThreshold" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019dbc7a-b286-768d-80f1-fcf17c216e4a_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of Shares</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityAddressPostalZipCode_019dbc7a-b286-7964-b6f6-8f3542849191_terseLabel_en-US" xlink:label="lab_dei_EntityAddressPostalZipCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Address, Postal Zip Code</link:label>
    <link:label id="lab_dei_EntityAddressPostalZipCode_label_en-US" xlink:label="lab_dei_EntityAddressPostalZipCode" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Address, Postal Zip Code</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressPostalZipCode"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressPostalZipCode" xlink:to="lab_dei_EntityAddressPostalZipCode" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_RestatementDeterminationDate_terseLabel_en-US" xlink:label="lab_ecd_RestatementDeterminationDate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Restatement Determination Date</link:label>
    <link:label id="lab_ecd_RestatementDeterminationDate_label_en-US" xlink:label="lab_ecd_RestatementDeterminationDate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Restatement Determination Date</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_RestatementDeterminationDate" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_RestatementDeterminationDate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_RestatementDeterminationDate" xlink:to="lab_ecd_RestatementDeterminationDate" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ResearchParkAustinTXMember_019dbc7a-b287-78a6-be84-3e34537407e1_terseLabel_en-US" xlink:label="lab_opi_ResearchParkAustinTXMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Research Park, Austin, TX</link:label>
    <link:label id="lab_opi_ResearchParkAustinTXMember_label_en-US" xlink:label="lab_opi_ResearchParkAustinTXMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Research Park, Austin, TX [Member]</link:label>
    <link:label id="lab_opi_ResearchParkAustinTXMember_documentation_en-US" xlink:label="lab_opi_ResearchParkAustinTXMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Research Park, Austin, TX [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ResearchParkAustinTXMember" xlink:href="opi-20251231.xsd#opi_ResearchParkAustinTXMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ResearchParkAustinTXMember" xlink:to="lab_opi_ResearchParkAustinTXMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxExpenseBenefit_019dbc7a-b1cb-7fc1-ba98-cb0cc819c1d4_negatedLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Income tax expense</link:label>
    <link:label id="lab_us-gaap_IncomeTaxExpenseBenefit_label_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Expense (Benefit)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxExpenseBenefit" xlink:to="lab_us-gaap_IncomeTaxExpenseBenefit" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LiabilitiesSubjectToCompromiseAccountsPayableAndOtherLiabilities_019dd0bb-1321-7736-92a2-6191863d8c9f_terseLabel_en-US" xlink:label="lab_opi_LiabilitiesSubjectToCompromiseAccountsPayableAndOtherLiabilities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts payable and other liabilities</link:label>
    <link:label id="lab_opi_LiabilitiesSubjectToCompromiseAccountsPayableAndOtherLiabilities_label_en-US" xlink:label="lab_opi_LiabilitiesSubjectToCompromiseAccountsPayableAndOtherLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities Subject to Compromise, Accounts Payable And Other Liabilities</link:label>
    <link:label id="lab_opi_LiabilitiesSubjectToCompromiseAccountsPayableAndOtherLiabilities_documentation_en-US" xlink:label="lab_opi_LiabilitiesSubjectToCompromiseAccountsPayableAndOtherLiabilities" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Liabilities Subject to Compromise, Accounts Payable And Other Liabilities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LiabilitiesSubjectToCompromiseAccountsPayableAndOtherLiabilities" xlink:href="opi-20251231.xsd#opi_LiabilitiesSubjectToCompromiseAccountsPayableAndOtherLiabilities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LiabilitiesSubjectToCompromiseAccountsPayableAndOtherLiabilities" xlink:to="lab_opi_LiabilitiesSubjectToCompromiseAccountsPayableAndOtherLiabilities" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019dbc7a-b1cb-79c0-92f6-9a0628b323bb_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate premium (as a percent)</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Basis Spread on Variable Rate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:to="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherAssets_019dbc7a-b1cb-74c1-abd1-3da2c761ba19_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other assets, net</link:label>
    <link:label id="lab_us-gaap_OtherAssets_label_en-US" xlink:label="lab_us-gaap_OtherAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssets" xlink:to="lab_us-gaap_OtherAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_UnsecuredDebt_019dbc7a-b1cb-7ebe-b244-626275059bd4_terseLabel_en-US" xlink:label="lab_us-gaap_UnsecuredDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unsecured debt, net</link:label>
    <link:label id="lab_us-gaap_UnsecuredDebt_label_en-US" xlink:label="lab_us-gaap_UnsecuredDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Unsecured Debt</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnsecuredDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_UnsecuredDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UnsecuredDebt" xlink:to="lab_us-gaap_UnsecuredDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_PnsnAdjsSvcCstMember_terseLabel_en-US" xlink:label="lab_ecd_PnsnAdjsSvcCstMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pension Adjustments Service Cost</link:label>
    <link:label id="lab_ecd_PnsnAdjsSvcCstMember_label_en-US" xlink:label="lab_ecd_PnsnAdjsSvcCstMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pension Adjustments Service Cost [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_PnsnAdjsSvcCstMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_PnsnAdjsSvcCstMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_PnsnAdjsSvcCstMember" xlink:to="lab_ecd_PnsnAdjsSvcCstMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodAggregateMarketValue_019dbc7a-b287-7608-8920-e0303d5fae54_terseLabel_en-US" xlink:label="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodAggregateMarketValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate market value of shares awarded</link:label>
    <link:label id="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodAggregateMarketValue_label_en-US" xlink:label="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodAggregateMarketValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options Grants In Period Aggregate Market Value</link:label>
    <link:label id="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodAggregateMarketValue_documentation_en-US" xlink:label="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodAggregateMarketValue" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the aggregate market value at grant date for nonvested equity-based awards during the period on other than stock (or unit) options plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodAggregateMarketValue" xlink:href="opi-20251231.xsd#opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodAggregateMarketValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodAggregateMarketValue" xlink:to="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodAggregateMarketValue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PrimeRateMember_019dd62b-91e3-7361-af59-6d2307475a01_terseLabel_en-US" xlink:label="lab_us-gaap_PrimeRateMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Prime Rate</link:label>
    <link:label id="lab_us-gaap_PrimeRateMember_label_en-US" xlink:label="lab_us-gaap_PrimeRateMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Prime Rate [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrimeRateMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PrimeRateMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PrimeRateMember" xlink:to="lab_us-gaap_PrimeRateMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A2020S.ArlingtonHeightsArlingtonHeightsILMember_019dbc7a-b287-75bf-a5a6-bb3c5b7de2ea_terseLabel_en-US" xlink:label="lab_opi_A2020S.ArlingtonHeightsArlingtonHeightsILMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2020 S. Arlington Heights, Arlington Heights, IL</link:label>
    <link:label id="lab_opi_A2020S.ArlingtonHeightsArlingtonHeightsILMember_label_en-US" xlink:label="lab_opi_A2020S.ArlingtonHeightsArlingtonHeightsILMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2020 S. Arlington Heights, Arlington Heights, IL [Member]</link:label>
    <link:label id="lab_opi_A2020S.ArlingtonHeightsArlingtonHeightsILMember_documentation_en-US" xlink:label="lab_opi_A2020S.ArlingtonHeightsArlingtonHeightsILMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2020 S. Arlington Heights, Arlington Heights, IL</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A2020S.ArlingtonHeightsArlingtonHeightsILMember" xlink:href="opi-20251231.xsd#opi_A2020S.ArlingtonHeightsArlingtonHeightsILMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A2020S.ArlingtonHeightsArlingtonHeightsILMember" xlink:to="lab_opi_A2020S.ArlingtonHeightsArlingtonHeightsILMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A440FirstStreetNWWashingtonDCMember_019dbc7a-b287-7568-80dd-cf0e7b41df5a_terseLabel_en-US" xlink:label="lab_opi_A440FirstStreetNWWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">440 First Street, NW, Washington DC</link:label>
    <link:label id="lab_opi_A440FirstStreetNWWashingtonDCMember_label_en-US" xlink:label="lab_opi_A440FirstStreetNWWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">440 First Street, NW, Washington DC [Member]</link:label>
    <link:label id="lab_opi_A440FirstStreetNWWashingtonDCMember_documentation_en-US" xlink:label="lab_opi_A440FirstStreetNWWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">440 First Street, NW, Washington DC [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A440FirstStreetNWWashingtonDCMember" xlink:href="opi-20251231.xsd#opi_A440FirstStreetNWWashingtonDCMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A440FirstStreetNWWashingtonDCMember" xlink:to="lab_opi_A440FirstStreetNWWashingtonDCMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_CompActuallyPaidVsCoSelectedMeasureTextBlock_terseLabel_en-US" xlink:label="lab_ecd_CompActuallyPaidVsCoSelectedMeasureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Compensation Actually Paid vs. Company Selected Measure</link:label>
    <link:label id="lab_ecd_CompActuallyPaidVsCoSelectedMeasureTextBlock_label_en-US" xlink:label="lab_ecd_CompActuallyPaidVsCoSelectedMeasureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Compensation Actually Paid vs. Company Selected Measure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_CompActuallyPaidVsCoSelectedMeasureTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_CompActuallyPaidVsCoSelectedMeasureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_CompActuallyPaidVsCoSelectedMeasureTextBlock" xlink:to="lab_ecd_CompActuallyPaidVsCoSelectedMeasureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFive_019dbc7a-b287-7ef7-8881-807ed89f362b_terseLabel_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2029</link:label>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFive_label_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Finance Costs Future Amortization Expense Year Five</link:label>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFive_documentation_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFive" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of amortization of deferred financing fees expected to be recognized during year five of the five succeeding fiscal years.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFive" xlink:href="opi-20251231.xsd#opi_DeferredFinanceCostsFutureAmortizationExpenseYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFive" xlink:to="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BuildingAndBuildingImprovementsMember_019dbc7a-b287-700c-a5e9-4457f7410bc6_terseLabel_en-US" xlink:label="lab_us-gaap_BuildingAndBuildingImprovementsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Building and Building Improvements</link:label>
    <link:label id="lab_us-gaap_BuildingAndBuildingImprovementsMember_label_en-US" xlink:label="lab_us-gaap_BuildingAndBuildingImprovementsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Building and Building Improvements [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BuildingAndBuildingImprovementsMember" xlink:to="lab_us-gaap_BuildingAndBuildingImprovementsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AllTradingArrangementsMember_terseLabel_en-US" xlink:label="lab_ecd_AllTradingArrangementsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">All Trading Arrangements</link:label>
    <link:label id="lab_ecd_AllTradingArrangementsMember_label_en-US" xlink:label="lab_ecd_AllTradingArrangementsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">All Trading Arrangements [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AllTradingArrangementsMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AllTradingArrangementsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AllTradingArrangementsMember" xlink:to="lab_ecd_AllTradingArrangementsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_EqtyAwrdsAdjFnTextBlock_terseLabel_en-US" xlink:label="lab_ecd_EqtyAwrdsAdjFnTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity Awards Adjustments, Footnote</link:label>
    <link:label id="lab_ecd_EqtyAwrdsAdjFnTextBlock_label_en-US" xlink:label="lab_ecd_EqtyAwrdsAdjFnTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Awards Adjustments, Footnote [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_EqtyAwrdsAdjFnTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_EqtyAwrdsAdjFnTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_EqtyAwrdsAdjFnTextBlock" xlink:to="lab_ecd_EqtyAwrdsAdjFnTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_TotalShareholderRtnVsPeerGroupTextBlock_terseLabel_en-US" xlink:label="lab_ecd_TotalShareholderRtnVsPeerGroupTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total Shareholder Return Vs Peer Group</link:label>
    <link:label id="lab_ecd_TotalShareholderRtnVsPeerGroupTextBlock_label_en-US" xlink:label="lab_ecd_TotalShareholderRtnVsPeerGroupTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Total Shareholder Return Vs Peer Group [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_TotalShareholderRtnVsPeerGroupTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_TotalShareholderRtnVsPeerGroupTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_TotalShareholderRtnVsPeerGroupTextBlock" xlink:to="lab_ecd_TotalShareholderRtnVsPeerGroupTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A25NewportAvenueQuincyMAMember_019dbc7a-b1cb-7e05-8c16-1433e9d4e049_terseLabel_en-US" xlink:label="lab_opi_A25NewportAvenueQuincyMAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">25 Newport Avenue, Quincy, MA</link:label>
    <link:label id="lab_opi_A25NewportAvenueQuincyMAMember_label_en-US" xlink:label="lab_opi_A25NewportAvenueQuincyMAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">25 Newport Avenue, Quincy, MA [Member]</link:label>
    <link:label id="lab_opi_A25NewportAvenueQuincyMAMember_documentation_en-US" xlink:label="lab_opi_A25NewportAvenueQuincyMAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">25 Newport Avenue, Quincy, MA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A25NewportAvenueQuincyMAMember" xlink:href="opi-20251231.xsd#opi_A25NewportAvenueQuincyMAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A25NewportAvenueQuincyMAMember" xlink:to="lab_opi_A25NewportAvenueQuincyMAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseAfterYearFive_019dbc7a-b30c-79f1-bf15-319a8ef2d10b_terseLabel_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Thereafter</link:label>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseAfterYearFive_label_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Finance Costs, Future Amortization Expense after Year Five</link:label>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseAfterYearFive_documentation_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of amortization of deferred financing fees expected to be recognized after the fifth succeeding fiscal year.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DeferredFinanceCostsFutureAmortizationExpenseAfterYearFive" xlink:href="opi-20251231.xsd#opi_DeferredFinanceCostsFutureAmortizationExpenseAfterYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DeferredFinanceCostsFutureAmortizationExpenseAfterYearFive" xlink:to="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseAfterYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_NoncashInvestingItemsAbstract_019dbc7a-b1cb-7bc0-bad9-e1386b7b5030_terseLabel_en-US" xlink:label="lab_opi_NoncashInvestingItemsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">NON-CASH INVESTING ACTIVITIES:</link:label>
    <link:label id="lab_opi_NoncashInvestingItemsAbstract_label_en-US" xlink:label="lab_opi_NoncashInvestingItemsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Noncash Investing Items [Abstract]</link:label>
    <link:label id="lab_opi_NoncashInvestingItemsAbstract_documentation_en-US" xlink:label="lab_opi_NoncashInvestingItemsAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Noncash Investing Items</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_NoncashInvestingItemsAbstract" xlink:href="opi-20251231.xsd#opi_NoncashInvestingItemsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_NoncashInvestingItemsAbstract" xlink:to="lab_opi_NoncashInvestingItemsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureAbstract_019dbc7a-b1cb-70e2-bcf2-b36de46bf648_terseLabel_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Abstract]</link:label>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureAbstract_label_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDisclosureAbstract" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RealEstateAndAccumulatedDepreciationDisclosureAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDisclosureAbstract" xlink:to="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019dbc7a-b287-7020-863e-d14a59ac45c0_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unvested shares (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019dbc7a-b287-72e2-a93b-a0062afdec15_periodStartLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Unvested at the beginning of the period (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019dbc7a-b287-7612-b768-793e157bb79f_periodEndLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Unvested at the end of the period (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_019dbc7a-b1cb-7d4c-9987-fa9fab0b6e5e_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash (used in) provided by operating activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Provided by (Used in) Operating Activity, Including Discontinued Operation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_AggregateGrossBookValueOfRealEstateAssetsCollateralized_019dbc7a-b287-7bab-8a32-a25685a8227b_terseLabel_en-US" xlink:label="lab_opi_AggregateGrossBookValueOfRealEstateAssetsCollateralized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate gross book value of real estate assets</link:label>
    <link:label id="lab_opi_AggregateGrossBookValueOfRealEstateAssetsCollateralized_label_en-US" xlink:label="lab_opi_AggregateGrossBookValueOfRealEstateAssetsCollateralized" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Aggregate Gross Book Value Of Real Estate Assets Collateralized</link:label>
    <link:label id="lab_opi_AggregateGrossBookValueOfRealEstateAssetsCollateralized_documentation_en-US" xlink:label="lab_opi_AggregateGrossBookValueOfRealEstateAssetsCollateralized" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the aggregate gross book value of real estate assets serving as a collateral for debt, as of the balance sheet date.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_AggregateGrossBookValueOfRealEstateAssetsCollateralized" xlink:href="opi-20251231.xsd#opi_AggregateGrossBookValueOfRealEstateAssetsCollateralized"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_AggregateGrossBookValueOfRealEstateAssetsCollateralized" xlink:to="lab_opi_AggregateGrossBookValueOfRealEstateAssetsCollateralized" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife_019dbc7a-b30c-7962-b9d1-96f973f1611e_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property, plant and equipment, useful life</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Useful Life</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SubsequentEventMember_019dbc7a-b287-7fd0-994e-fb2dc9569c64_terseLabel_en-US" xlink:label="lab_us-gaap_SubsequentEventMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Subsequent Event</link:label>
    <link:label id="lab_us-gaap_SubsequentEventMember_label_en-US" xlink:label="lab_us-gaap_SubsequentEventMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Subsequent Event [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsequentEventMember" xlink:to="lab_us-gaap_SubsequentEventMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateLineItems_019dbc7a-b286-7ff1-8dae-53f0179b301c_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate [Line Items]</link:label>
    <link:label id="lab_us-gaap_RealEstateLineItems_label_en-US" xlink:label="lab_us-gaap_RealEstateLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateLineItems" xlink:to="lab_us-gaap_RealEstateLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019dbc7a-b1cb-709e-ab64-86a12b261821_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Equity Method Investments [Line Items]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_label_en-US" xlink:label="lab_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Equity Method Investments [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="lab_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_EquityValuationAssumptionDifferenceFnTextBlock_terseLabel_en-US" xlink:label="lab_ecd_EquityValuationAssumptionDifferenceFnTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity Valuation Assumption Difference, Footnote</link:label>
    <link:label id="lab_ecd_EquityValuationAssumptionDifferenceFnTextBlock_label_en-US" xlink:label="lab_ecd_EquityValuationAssumptionDifferenceFnTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Valuation Assumption Difference, Footnote [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_EquityValuationAssumptionDifferenceFnTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_EquityValuationAssumptionDifferenceFnTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_EquityValuationAssumptionDifferenceFnTextBlock" xlink:to="lab_ecd_EquityValuationAssumptionDifferenceFnTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_PeoTotalCompAmt_terseLabel_en-US" xlink:label="lab_ecd_PeoTotalCompAmt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">PEO Total Compensation Amount</link:label>
    <link:label id="lab_ecd_PeoTotalCompAmt_label_en-US" xlink:label="lab_ecd_PeoTotalCompAmt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">PEO Total Compensation Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_PeoTotalCompAmt" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_PeoTotalCompAmt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_PeoTotalCompAmt" xlink:to="lab_ecd_PeoTotalCompAmt" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongtermDebtTypeAxis_019dbc7a-b287-74ca-9d04-caae1ee77f26_terseLabel_en-US" xlink:label="lab_us-gaap_LongtermDebtTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Long-term Debt, Type [Axis]</link:label>
    <link:label id="lab_us-gaap_LongtermDebtTypeAxis_label_en-US" xlink:label="lab_us-gaap_LongtermDebtTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Type [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongtermDebtTypeAxis" xlink:to="lab_us-gaap_LongtermDebtTypeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_Depreciation_019dbc85-0459-77b9-b3f3-13ee87e0c709_terseLabel_en-US" xlink:label="lab_us-gaap_Depreciation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Depreciation</link:label>
    <link:label id="lab_us-gaap_Depreciation_label_en-US" xlink:label="lab_us-gaap_Depreciation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Depreciation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Depreciation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Depreciation" xlink:to="lab_us-gaap_Depreciation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract_019dbc7a-b287-7331-a6ba-2f645d66daa7_terseLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Denominators:</link:label>
    <link:label id="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract_label_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Weighted Average Number of Shares Outstanding, Basic [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract" xlink:to="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SeniorNotesExchangeMember_019dd0d3-7bfb-7a83-8a15-943d48974e9d_terseLabel_en-US" xlink:label="lab_opi_SeniorNotesExchangeMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior Notes Exchange</link:label>
    <link:label id="lab_opi_SeniorNotesExchangeMember_label_en-US" xlink:label="lab_opi_SeniorNotesExchangeMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Senior Notes Exchange [Member]</link:label>
    <link:label id="lab_opi_SeniorNotesExchangeMember_documentation_en-US" xlink:label="lab_opi_SeniorNotesExchangeMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Senior Notes Exchange</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SeniorNotesExchangeMember" xlink:href="opi-20251231.xsd#opi_SeniorNotesExchangeMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SeniorNotesExchangeMember" xlink:to="lab_opi_SeniorNotesExchangeMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementEquityComponentsAxis_019dbc7a-b1cb-750b-8fa0-07858641ab2c_terseLabel_en-US" xlink:label="lab_us-gaap_StatementEquityComponentsAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity Components [Axis]</link:label>
    <link:label id="lab_us-gaap_StatementEquityComponentsAxis_label_en-US" xlink:label="lab_us-gaap_StatementEquityComponentsAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Components [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementEquityComponentsAxis" xlink:to="lab_us-gaap_StatementEquityComponentsAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstatePropertiesLineItems_019dbc7a-b1cb-75b1-a37f-177524b56616_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstatePropertiesLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate Properties [Line Items]</link:label>
    <link:label id="lab_us-gaap_RealEstatePropertiesLineItems_label_en-US" xlink:label="lab_us-gaap_RealEstatePropertiesLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Properties [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstatePropertiesLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstatePropertiesLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems" xlink:to="lab_us-gaap_RealEstatePropertiesLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A4221W.JohnCarpenterFreewayIrvingTXMember_019dbc7a-b287-7b27-b28d-dd71d2b3bf4a_terseLabel_en-US" xlink:label="lab_opi_A4221W.JohnCarpenterFreewayIrvingTXMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">4221 W. John Carpenter Freeway, Irving, TX</link:label>
    <link:label id="lab_opi_A4221W.JohnCarpenterFreewayIrvingTXMember_label_en-US" xlink:label="lab_opi_A4221W.JohnCarpenterFreewayIrvingTXMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">4221 W. John Carpenter Freeway, Irving, TX [Member]</link:label>
    <link:label id="lab_opi_A4221W.JohnCarpenterFreewayIrvingTXMember_documentation_en-US" xlink:label="lab_opi_A4221W.JohnCarpenterFreewayIrvingTXMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">4221 W. John Carpenter Freeway, Irving, TX [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A4221W.JohnCarpenterFreewayIrvingTXMember" xlink:href="opi-20251231.xsd#opi_A4221W.JohnCarpenterFreewayIrvingTXMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A4221W.JohnCarpenterFreewayIrvingTXMember" xlink:to="lab_opi_A4221W.JohnCarpenterFreewayIrvingTXMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReorganizationChapter11LineItems_019dd081-dfd7-7308-b582-8db4c5774a1d_terseLabel_en-US" xlink:label="lab_us-gaap_ReorganizationChapter11LineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reorganization, Chapter 11 [Line Items]</link:label>
    <link:label id="lab_us-gaap_ReorganizationChapter11LineItems_label_en-US" xlink:label="lab_us-gaap_ReorganizationChapter11LineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reorganization, Chapter 11 [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReorganizationChapter11LineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReorganizationChapter11LineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReorganizationChapter11LineItems" xlink:to="lab_us-gaap_ReorganizationChapter11LineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_NonRule10b51ArrAdoptedFlag_terseLabel_en-US" xlink:label="lab_ecd_NonRule10b51ArrAdoptedFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Non-Rule 10b5-1 Arrangement Adopted</link:label>
    <link:label id="lab_ecd_NonRule10b51ArrAdoptedFlag_label_en-US" xlink:label="lab_ecd_NonRule10b51ArrAdoptedFlag" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Non-Rule 10b5-1 Arrangement Adopted [Flag]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_NonRule10b51ArrAdoptedFlag" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_NonRule10b51ArrAdoptedFlag"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_NonRule10b51ArrAdoptedFlag" xlink:to="lab_ecd_NonRule10b51ArrAdoptedFlag" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NumberOfReportableSegments_019dbc7a-b287-741e-9a42-db44a98975ac_terseLabel_en-US" xlink:label="lab_us-gaap_NumberOfReportableSegments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of reportable segments</link:label>
    <link:label id="lab_us-gaap_NumberOfReportableSegments_label_en-US" xlink:label="lab_us-gaap_NumberOfReportableSegments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Reportable Segments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NumberOfReportableSegments" xlink:to="lab_us-gaap_NumberOfReportableSegments" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ExpenseReimbursementMember_019dbc7a-b286-733b-a2c4-d58afe605025_terseLabel_en-US" xlink:label="lab_opi_ExpenseReimbursementMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Expense Reimbursement</link:label>
    <link:label id="lab_opi_ExpenseReimbursementMember_label_en-US" xlink:label="lab_opi_ExpenseReimbursementMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Expense Reimbursement [Member]</link:label>
    <link:label id="lab_opi_ExpenseReimbursementMember_documentation_en-US" xlink:label="lab_opi_ExpenseReimbursementMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Expense Reimbursement</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ExpenseReimbursementMember" xlink:href="opi-20251231.xsd#opi_ExpenseReimbursementMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ExpenseReimbursementMember" xlink:to="lab_opi_ExpenseReimbursementMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_IndianapolisINMember_019dbc7a-b287-7c8c-8257-430f49a4827b_terseLabel_en-US" xlink:label="lab_opi_IndianapolisINMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Indianapolis, IN</link:label>
    <link:label id="lab_opi_IndianapolisINMember_label_en-US" xlink:label="lab_opi_IndianapolisINMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Indianapolis, IN [Member]</link:label>
    <link:label id="lab_opi_IndianapolisINMember_documentation_en-US" xlink:label="lab_opi_IndianapolisINMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Indianapolis, IN</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_IndianapolisINMember" xlink:href="opi-20251231.xsd#opi_IndianapolisINMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_IndianapolisINMember" xlink:to="lab_opi_IndianapolisINMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InterestAndOtherIncome_019dbc7a-b1cb-75a0-bfd5-2a070767cc36_terseLabel_en-US" xlink:label="lab_us-gaap_InterestAndOtherIncome" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest and other income</link:label>
    <link:label id="lab_us-gaap_InterestAndOtherIncome_label_en-US" xlink:label="lab_us-gaap_InterestAndOtherIncome" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest and Other Income</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestAndOtherIncome" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestAndOtherIncome"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestAndOtherIncome" xlink:to="lab_us-gaap_InterestAndOtherIncome" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DeferredFinancingFeesPolicyTextBlock_019dbc7a-b287-7b70-bfc3-31c12325f8c1_terseLabel_en-US" xlink:label="lab_opi_DeferredFinancingFeesPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Issuance Costs</link:label>
    <link:label id="lab_opi_DeferredFinancingFeesPolicyTextBlock_label_en-US" xlink:label="lab_opi_DeferredFinancingFeesPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Financing Fees [Policy Text Block]</link:label>
    <link:label id="lab_opi_DeferredFinancingFeesPolicyTextBlock_documentation_en-US" xlink:label="lab_opi_DeferredFinancingFeesPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Disclosure of accounting policy for costs incurred to obtain or issue debt, method of amortizing deferred financing costs and original issue discount.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DeferredFinancingFeesPolicyTextBlock" xlink:href="opi-20251231.xsd#opi_DeferredFinancingFeesPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DeferredFinancingFeesPolicyTextBlock" xlink:to="lab_opi_DeferredFinancingFeesPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A18020BurtStreetOmahaNEMember_019dbc7a-b287-7ca8-9902-00177ef9d543_terseLabel_en-US" xlink:label="lab_opi_A18020BurtStreetOmahaNEMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">18020 Burt Street, Omaha, NE</link:label>
    <link:label id="lab_opi_A18020BurtStreetOmahaNEMember_label_en-US" xlink:label="lab_opi_A18020BurtStreetOmahaNEMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">18020 Burt Street, Omaha, NE [Member]</link:label>
    <link:label id="lab_opi_A18020BurtStreetOmahaNEMember_documentation_en-US" xlink:label="lab_opi_A18020BurtStreetOmahaNEMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">18020 Burt Street, Omaha, NE</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A18020BurtStreetOmahaNEMember" xlink:href="opi-20251231.xsd#opi_A18020BurtStreetOmahaNEMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A18020BurtStreetOmahaNEMember" xlink:to="lab_opi_A18020BurtStreetOmahaNEMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionMaximumPriorityReturnOfPriorYearPriorityReturn_019dbc7a-b286-70ca-957f-7b927393829b_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionMaximumPriorityReturnOfPriorYearPriorityReturn" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Priority return percentage of prior year's annual owner's priority return</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionMaximumPriorityReturnOfPriorYearPriorityReturn_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionMaximumPriorityReturnOfPriorYearPriorityReturn" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Maximum Priority Return Of Prior Year Priority Return</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionMaximumPriorityReturnOfPriorYearPriorityReturn_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionMaximumPriorityReturnOfPriorYearPriorityReturn" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Maximum Priority Return Of Prior Year Priority Return</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionMaximumPriorityReturnOfPriorYearPriorityReturn" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionMaximumPriorityReturnOfPriorYearPriorityReturn"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionMaximumPriorityReturnOfPriorYearPriorityReturn" xlink:to="lab_opi_RelatedPartyTransactionMaximumPriorityReturnOfPriorYearPriorityReturn" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityAddressStateOrProvince_019dbc7a-b1cb-7e76-93d9-825b56b0ef42_terseLabel_en-US" xlink:label="lab_dei_EntityAddressStateOrProvince" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Address, State or Province</link:label>
    <link:label id="lab_dei_EntityAddressStateOrProvince_label_en-US" xlink:label="lab_dei_EntityAddressStateOrProvince" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Address, State or Province</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressStateOrProvince"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressStateOrProvince" xlink:to="lab_dei_EntityAddressStateOrProvince" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateOtherAcquisitions_019dbc7a-b1cb-78d5-b8f5-31ff0272b5c2_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateOtherAcquisitions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Additions</link:label>
    <link:label id="lab_us-gaap_RealEstateOtherAcquisitions_label_en-US" xlink:label="lab_us-gaap_RealEstateOtherAcquisitions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Other Acquisition</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateOtherAcquisitions" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateOtherAcquisitions"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateOtherAcquisitions" xlink:to="lab_us-gaap_RealEstateOtherAcquisitions" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DividendsCommonStock_019dbc7a-b1cb-7520-b3df-4f2ae582a5a7_terseLabel_en-US" xlink:label="lab_us-gaap_DividendsCommonStock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total Distributions</link:label>
    <link:label id="lab_us-gaap_DividendsCommonStock_label_en-US" xlink:label="lab_us-gaap_DividendsCommonStock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dividends, Common Stock</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DividendsCommonStock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DividendsCommonStock" xlink:to="lab_us-gaap_DividendsCommonStock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A10451ClayRoadHoustonTXMember_019dbc7a-b287-77fe-9b30-60f34b91a297_terseLabel_en-US" xlink:label="lab_opi_A10451ClayRoadHoustonTXMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">10451 Clay Road, Houston, TX</link:label>
    <link:label id="lab_opi_A10451ClayRoadHoustonTXMember_label_en-US" xlink:label="lab_opi_A10451ClayRoadHoustonTXMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">10451 Clay Road, Houston, TX [Member]</link:label>
    <link:label id="lab_opi_A10451ClayRoadHoustonTXMember_documentation_en-US" xlink:label="lab_opi_A10451ClayRoadHoustonTXMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">10451 Clay Road, Houston, TX [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A10451ClayRoadHoustonTXMember" xlink:href="opi-20251231.xsd#opi_A10451ClayRoadHoustonTXMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A10451ClayRoadHoustonTXMember" xlink:to="lab_opi_A10451ClayRoadHoustonTXMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_IndividualAxis_terseLabel_en-US" xlink:label="lab_ecd_IndividualAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Individual:</link:label>
    <link:label id="lab_ecd_IndividualAxis_label_en-US" xlink:label="lab_ecd_IndividualAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Individual [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_IndividualAxis" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_IndividualAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_IndividualAxis" xlink:to="lab_ecd_IndividualAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_USGovernmentMember_019dbc7a-b1cb-72ff-a094-0d65a313aea3_terseLabel_en-US" xlink:label="lab_opi_USGovernmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">U.S. Government</link:label>
    <link:label id="lab_opi_USGovernmentMember_label_en-US" xlink:label="lab_opi_USGovernmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">U S Government [Member]</link:label>
    <link:label id="lab_opi_USGovernmentMember_documentation_en-US" xlink:label="lab_opi_USGovernmentMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents information pertaining to the government of United States of America.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_USGovernmentMember" xlink:href="opi-20251231.xsd#opi_USGovernmentMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_USGovernmentMember" xlink:to="lab_opi_USGovernmentMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsOfDividendsCommonStock_019dbc8d-574d-736f-940c-e7f1ee0c283e_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsOfDividendsCommonStock" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Distributions to common shareholders</link:label>
    <link:label id="lab_us-gaap_PaymentsOfDividendsCommonStock_label_en-US" xlink:label="lab_us-gaap_PaymentsOfDividendsCommonStock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments of Ordinary Dividends, Common Stock</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDividendsCommonStock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsOfDividendsCommonStock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsOfDividendsCommonStock" xlink:to="lab_us-gaap_PaymentsOfDividendsCommonStock" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentAnnualReport_019dbc7a-b1cb-755f-81cd-c303f14a514c_terseLabel_en-US" xlink:label="lab_dei_DocumentAnnualReport" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Document Annual Report</link:label>
    <link:label id="lab_dei_DocumentAnnualReport_label_en-US" xlink:label="lab_dei_DocumentAnnualReport" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Document Annual Report</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentAnnualReport" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentAnnualReport"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentAnnualReport" xlink:to="lab_dei_DocumentAnnualReport" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CumulativeDividends_019dbc7a-b1cb-710d-ae4a-7154d91a9e28_negatedLabel_en-US" xlink:label="lab_us-gaap_CumulativeDividends" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Cumulative common distributions</link:label>
    <link:label id="lab_us-gaap_CumulativeDividends_label_en-US" xlink:label="lab_us-gaap_CumulativeDividends" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cumulative Dividends</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CumulativeDividends" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CumulativeDividends"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CumulativeDividends" xlink:to="lab_us-gaap_CumulativeDividends" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A2555GrandBoulevardKansasCityMOMember_019dbc7a-b287-776b-b062-cc1588ce89ab_terseLabel_en-US" xlink:label="lab_opi_A2555GrandBoulevardKansasCityMOMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2555 Grand Boulevard, Kansas City, MO</link:label>
    <link:label id="lab_opi_A2555GrandBoulevardKansasCityMOMember_label_en-US" xlink:label="lab_opi_A2555GrandBoulevardKansasCityMOMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2555 Grand Boulevard, Kansas City, MO [Member]</link:label>
    <link:label id="lab_opi_A2555GrandBoulevardKansasCityMOMember_documentation_en-US" xlink:label="lab_opi_A2555GrandBoulevardKansasCityMOMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2555 Grand Boulevard, Kansas City, MO [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A2555GrandBoulevardKansasCityMOMember" xlink:href="opi-20251231.xsd#opi_A2555GrandBoulevardKansasCityMOMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A2555GrandBoulevardKansasCityMOMember" xlink:to="lab_opi_A2555GrandBoulevardKansasCityMOMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A840FirstStreetNEWashingtonDCMember_019dbc7a-b1cb-71a2-8ff0-46077f363ccb_terseLabel_en-US" xlink:label="lab_opi_A840FirstStreetNEWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">840 First Street, NE, Washington DC</link:label>
    <link:label id="lab_opi_A840FirstStreetNEWashingtonDCMember_label_en-US" xlink:label="lab_opi_A840FirstStreetNEWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">840 First Street, NE, Washington DC [Member]</link:label>
    <link:label id="lab_opi_A840FirstStreetNEWashingtonDCMember_documentation_en-US" xlink:label="lab_opi_A840FirstStreetNEWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">840 First Street, NE, Washington DC [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A840FirstStreetNEWashingtonDCMember" xlink:href="opi-20251231.xsd#opi_A840FirstStreetNEWashingtonDCMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A840FirstStreetNEWashingtonDCMember" xlink:to="lab_opi_A840FirstStreetNEWashingtonDCMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ParsippanyNJMember_019dbc9c-d30e-783c-a5df-0b4bd9276f9b_terseLabel_en-US" xlink:label="lab_opi_ParsippanyNJMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Parsippany, NJ</link:label>
    <link:label id="lab_opi_ParsippanyNJMember_label_en-US" xlink:label="lab_opi_ParsippanyNJMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Parsippany, NJ [Member]</link:label>
    <link:label id="lab_opi_ParsippanyNJMember_documentation_en-US" xlink:label="lab_opi_ParsippanyNJMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Parsippany, NJ</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ParsippanyNJMember" xlink:href="opi-20251231.xsd#opi_ParsippanyNJMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ParsippanyNJMember" xlink:to="lab_opi_ParsippanyNJMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_ForgoneRecoveryExplanationOfImpracticabilityTextBlock_terseLabel_en-US" xlink:label="lab_ecd_ForgoneRecoveryExplanationOfImpracticabilityTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Forgone Recovery, Explanation of Impracticability</link:label>
    <link:label id="lab_ecd_ForgoneRecoveryExplanationOfImpracticabilityTextBlock_label_en-US" xlink:label="lab_ecd_ForgoneRecoveryExplanationOfImpracticabilityTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Forgone Recovery, Explanation of Impracticability [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_ForgoneRecoveryExplanationOfImpracticabilityTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_ForgoneRecoveryExplanationOfImpracticabilityTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_ForgoneRecoveryExplanationOfImpracticabilityTextBlock" xlink:to="lab_ecd_ForgoneRecoveryExplanationOfImpracticabilityTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReorganizationChapter11DebtorInPossessionMember_019dd081-dfd7-7ea8-9501-fcdf4ef3ae48_terseLabel_en-US" xlink:label="lab_us-gaap_ReorganizationChapter11DebtorInPossessionMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reorganization, Chapter 11, Debtor-in-Possession</link:label>
    <link:label id="lab_us-gaap_ReorganizationChapter11DebtorInPossessionMember_label_en-US" xlink:label="lab_us-gaap_ReorganizationChapter11DebtorInPossessionMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reorganization, Chapter 11, Debtor-in-Possession [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReorganizationChapter11DebtorInPossessionMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReorganizationChapter11DebtorInPossessionMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReorganizationChapter11DebtorInPossessionMember" xlink:to="lab_us-gaap_ReorganizationChapter11DebtorInPossessionMember" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityInteractiveDataCurrent_019dbc7a-b287-7545-93a3-589919c7bb02_terseLabel_en-US" xlink:label="lab_dei_EntityInteractiveDataCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Interactive Data Current</link:label>
    <link:label id="lab_dei_EntityInteractiveDataCurrent_label_en-US" xlink:label="lab_dei_EntityInteractiveDataCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Interactive Data Current</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityInteractiveDataCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityInteractiveDataCurrent" xlink:to="lab_dei_EntityInteractiveDataCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAverageMarketCapitalization_019dbc7a-b1cb-739c-84e4-d2fa982b85cd_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAverageMarketCapitalization" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Base management fee payable average market capitalization</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAverageMarketCapitalization_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAverageMarketCapitalization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction Base Management Fee Payable Average Market Capitalization</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAverageMarketCapitalization_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAverageMarketCapitalization" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of average market capitalization for payment of base management fee.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionBaseManagementFeePayableAverageMarketCapitalization" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionBaseManagementFeePayableAverageMarketCapitalization"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionBaseManagementFeePayableAverageMarketCapitalization" xlink:to="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAverageMarketCapitalization" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SonestaManagementAgreementPeriodThreeMember_019dbc7a-b30c-74dd-8b60-14f82eb4e369_terseLabel_en-US" xlink:label="lab_opi_SonestaManagementAgreementPeriodThreeMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sonesta Management Agreement, Period Three</link:label>
    <link:label id="lab_opi_SonestaManagementAgreementPeriodThreeMember_label_en-US" xlink:label="lab_opi_SonestaManagementAgreementPeriodThreeMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sonesta Management Agreement, Period Three [Member]</link:label>
    <link:label id="lab_opi_SonestaManagementAgreementPeriodThreeMember_documentation_en-US" xlink:label="lab_opi_SonestaManagementAgreementPeriodThreeMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sonesta Management Agreement, Period Three</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SonestaManagementAgreementPeriodThreeMember" xlink:href="opi-20251231.xsd#opi_SonestaManagementAgreementPeriodThreeMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SonestaManagementAgreementPeriodThreeMember" xlink:to="lab_opi_SonestaManagementAgreementPeriodThreeMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock_019dbc7a-b287-7814-acde-673096ce310b_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revenue Recognition</link:label>
    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue from Contract with Customer [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock" xlink:to="lab_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAccumulatedDepreciationOtherAdditions_019dbc7a-b30c-7b96-8a75-723db7fb37d0_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAccumulatedDepreciationOtherAdditions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Additions</link:label>
    <link:label id="lab_us-gaap_RealEstateAccumulatedDepreciationOtherAdditions_label_en-US" xlink:label="lab_us-gaap_RealEstateAccumulatedDepreciationOtherAdditions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation, Other Addition</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAccumulatedDepreciationOtherAdditions" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAccumulatedDepreciationOtherAdditions"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAccumulatedDepreciationOtherAdditions" xlink:to="lab_us-gaap_RealEstateAccumulatedDepreciationOtherAdditions" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentPeriodicPaymentPrincipal_019dd0ce-a18a-7259-87ba-d504d3ffec66_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentPeriodicPaymentPrincipal" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Repayments of principal debt</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentPeriodicPaymentPrincipal_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentPeriodicPaymentPrincipal" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Periodic Payment, Principal</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentPeriodicPaymentPrincipal" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentPeriodicPaymentPrincipal"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentPeriodicPaymentPrincipal" xlink:to="lab_us-gaap_DebtInstrumentPeriodicPaymentPrincipal" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearTwo_019dbc7a-b1cb-7c13-836b-8e6f47a301d4_terseLabel_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2026</link:label>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearTwo_label_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Finance Costs, Future Amortization Expense Year Two</link:label>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearTwo_documentation_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearTwo" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of amortization of deferred financing fees expected to be recognized during year two of the five succeeding fiscal years.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DeferredFinanceCostsFutureAmortizationExpenseYearTwo" xlink:href="opi-20251231.xsd#opi_DeferredFinanceCostsFutureAmortizationExpenseYearTwo"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DeferredFinanceCostsFutureAmortizationExpenseYearTwo" xlink:to="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearTwo" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements_019dbc7a-b287-73d5-9d14-29fd1ffcdeeb_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Costs Capitalized Subsequent to Acquisition</link:label>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements_label_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition, Improvements</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements" xlink:to="lab_us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A701ClayRoadWacoTXMember_019dbc7a-b286-77cb-b6dc-0c6be854bc05_terseLabel_en-US" xlink:label="lab_opi_A701ClayRoadWacoTXMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">701 Clay Road, Waco, TX</link:label>
    <link:label id="lab_opi_A701ClayRoadWacoTXMember_label_en-US" xlink:label="lab_opi_A701ClayRoadWacoTXMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">701 Clay Road, Waco, TX [Member]</link:label>
    <link:label id="lab_opi_A701ClayRoadWacoTXMember_documentation_en-US" xlink:label="lab_opi_A701ClayRoadWacoTXMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">701 Clay Road, Waco, TX</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A701ClayRoadWacoTXMember" xlink:href="opi-20251231.xsd#opi_A701ClayRoadWacoTXMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A701ClayRoadWacoTXMember" xlink:to="lab_opi_A701ClayRoadWacoTXMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_UpCTransactionMember_019dbc7a-b287-70f6-82c1-fc94819acfa5_terseLabel_en-US" xlink:label="lab_opi_UpCTransactionMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Up C Transaction</link:label>
    <link:label id="lab_opi_UpCTransactionMember_label_en-US" xlink:label="lab_opi_UpCTransactionMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Up C Transaction [Member]</link:label>
    <link:label id="lab_opi_UpCTransactionMember_documentation_en-US" xlink:label="lab_opi_UpCTransactionMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Information pertaining to the related party Up-C Transaction.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_UpCTransactionMember" xlink:href="opi-20251231.xsd#opi_UpCTransactionMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_UpCTransactionMember" xlink:to="lab_opi_UpCTransactionMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand_019dbc7a-b1cb-7f96-9a6e-b4b435907db1_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Land</link:label>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand_label_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost of Land</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand" xlink:to="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A1511EastCommonStreetNewBraunfelsTXMember_019dbc7a-b1cb-798d-bad8-faad60cce2e3_terseLabel_en-US" xlink:label="lab_opi_A1511EastCommonStreetNewBraunfelsTXMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">1511 East Common Street, New Braunfels, TX</link:label>
    <link:label id="lab_opi_A1511EastCommonStreetNewBraunfelsTXMember_label_en-US" xlink:label="lab_opi_A1511EastCommonStreetNewBraunfelsTXMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">1511 East Common Street, New Braunfels, TX [Member]</link:label>
    <link:label id="lab_opi_A1511EastCommonStreetNewBraunfelsTXMember_documentation_en-US" xlink:label="lab_opi_A1511EastCommonStreetNewBraunfelsTXMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">1511 East Common Street, New Braunfels, TX [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A1511EastCommonStreetNewBraunfelsTXMember" xlink:href="opi-20251231.xsd#opi_A1511EastCommonStreetNewBraunfelsTXMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A1511EastCommonStreetNewBraunfelsTXMember" xlink:to="lab_opi_A1511EastCommonStreetNewBraunfelsTXMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_Redland520530RockvilleMDMember_019dbc7a-b287-7c1f-973d-eb02c79eeda8_terseLabel_en-US" xlink:label="lab_opi_Redland520530RockvilleMDMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Redland 520/530, Rockville, MD</link:label>
    <link:label id="lab_opi_Redland520530RockvilleMDMember_label_en-US" xlink:label="lab_opi_Redland520530RockvilleMDMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Redland 520/530, Rockville, MD [Member]</link:label>
    <link:label id="lab_opi_Redland520530RockvilleMDMember_documentation_en-US" xlink:label="lab_opi_Redland520530RockvilleMDMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Redland 520/530, Rockville, MD [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_Redland520530RockvilleMDMember" xlink:href="opi-20251231.xsd#opi_Redland520530RockvilleMDMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_Redland520530RockvilleMDMember" xlink:to="lab_opi_Redland520530RockvilleMDMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredCostsLeasingAccumulatedAmortization_019dbc7a-b1cb-762d-b713-8a47a38c560a_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredCostsLeasingAccumulatedAmortization" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accumulated amortization of deferred leasing costs</link:label>
    <link:label id="lab_us-gaap_DeferredCostsLeasingAccumulatedAmortization_label_en-US" xlink:label="lab_us-gaap_DeferredCostsLeasingAccumulatedAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Costs, Leasing, Accumulated Amortization</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCostsLeasingAccumulatedAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredCostsLeasingAccumulatedAmortization"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredCostsLeasingAccumulatedAmortization" xlink:to="lab_us-gaap_DeferredCostsLeasingAccumulatedAmortization" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock_019dbc7a-b1cb-7959-a712-4aa394aa889f_terseLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Future Contractual Lease Payments to be Received</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received, Maturity [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock" xlink:to="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DebtInstrumentUpfrontFeePercentageReorganizedCommonEquityCommitment_019dd61c-f280-78dd-b2ba-33d8e3a825f2_terseLabel_en-US" xlink:label="lab_opi_DebtInstrumentUpfrontFeePercentageReorganizedCommonEquityCommitment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reorganized common equity percentage of commitments as an upfront fee</link:label>
    <link:label id="lab_opi_DebtInstrumentUpfrontFeePercentageReorganizedCommonEquityCommitment_label_en-US" xlink:label="lab_opi_DebtInstrumentUpfrontFeePercentageReorganizedCommonEquityCommitment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Upfront Fee Percentage, Reorganized Common Equity Commitment</link:label>
    <link:label id="lab_opi_DebtInstrumentUpfrontFeePercentageReorganizedCommonEquityCommitment_documentation_en-US" xlink:label="lab_opi_DebtInstrumentUpfrontFeePercentageReorganizedCommonEquityCommitment" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Upfront Fee, Reorganized Common Equity Commitment Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DebtInstrumentUpfrontFeePercentageReorganizedCommonEquityCommitment" xlink:href="opi-20251231.xsd#opi_DebtInstrumentUpfrontFeePercentageReorganizedCommonEquityCommitment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DebtInstrumentUpfrontFeePercentageReorganizedCommonEquityCommitment" xlink:to="lab_opi_DebtInstrumentUpfrontFeePercentageReorganizedCommonEquityCommitment" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_NameOfMajorCustomerDomain_019dbc7a-b286-7b32-af1c-d83f4d9b796b_terseLabel_en-US" xlink:label="lab_srt_NameOfMajorCustomerDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Customer [Domain]</link:label>
    <link:label id="lab_srt_NameOfMajorCustomerDomain_label_en-US" xlink:label="lab_srt_NameOfMajorCustomerDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Customer [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_NameOfMajorCustomerDomain" xlink:to="lab_srt_NameOfMajorCustomerDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_WestfordMAMember_019dbc7a-b287-7567-846f-8972927c60aa_terseLabel_en-US" xlink:label="lab_opi_WestfordMAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Westford, MA</link:label>
    <link:label id="lab_opi_WestfordMAMember_label_en-US" xlink:label="lab_opi_WestfordMAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Westford, MA [Member]</link:label>
    <link:label id="lab_opi_WestfordMAMember_documentation_en-US" xlink:label="lab_opi_WestfordMAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Westford, MA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_WestfordMAMember" xlink:href="opi-20251231.xsd#opi_WestfordMAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_WestfordMAMember" xlink:to="lab_opi_WestfordMAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseAfterYearFive_019dbc7a-b287-727c-9610-0891652e54c4_terseLabel_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Thereafter</link:label>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseAfterYearFive_label_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Costs, Leasing Future Amortization Expense after Year Five</link:label>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseAfterYearFive_documentation_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of amortization of deferred leasing costs expected to be recognized after the fifth succeeding fiscal year.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DeferredCostsLeasingFutureAmortizationExpenseAfterYearFive" xlink:href="opi-20251231.xsd#opi_DeferredCostsLeasingFutureAmortizationExpenseAfterYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DeferredCostsLeasingFutureAmortizationExpenseAfterYearFive" xlink:to="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseAfterYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityCentralIndexKey_019dbc7a-b286-7206-85e8-c533d5644806_terseLabel_en-US" xlink:label="lab_dei_EntityCentralIndexKey" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Central Index Key</link:label>
    <link:label id="lab_dei_EntityCentralIndexKey_label_en-US" xlink:label="lab_dei_EntityCentralIndexKey" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Central Index Key</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityCentralIndexKey"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityCentralIndexKey" xlink:to="lab_dei_EntityCentralIndexKey" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_PeoName_terseLabel_en-US" xlink:label="lab_ecd_PeoName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">PEO Name</link:label>
    <link:label id="lab_ecd_PeoName_label_en-US" xlink:label="lab_ecd_PeoName" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">PEO Name</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_PeoName" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_PeoName"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_PeoName" xlink:to="lab_ecd_PeoName" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A867587018711FreeportPkwyAnd8901EstersBoulevardIrvingTXMember_019dbc7a-b287-737a-ae9b-e616ad17e6d5_terseLabel_en-US" xlink:label="lab_opi_A867587018711FreeportPkwyAnd8901EstersBoulevardIrvingTXMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">8675, 8701-8711 Freeport Pkwy and 8901 Esters Boulevard, Irving, TX</link:label>
    <link:label id="lab_opi_A867587018711FreeportPkwyAnd8901EstersBoulevardIrvingTXMember_label_en-US" xlink:label="lab_opi_A867587018711FreeportPkwyAnd8901EstersBoulevardIrvingTXMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">8675,8701-8711 Freeport Pkwy and 8901 Esters Boulevard, Irving, TX [Member]</link:label>
    <link:label id="lab_opi_A867587018711FreeportPkwyAnd8901EstersBoulevardIrvingTXMember_documentation_en-US" xlink:label="lab_opi_A867587018711FreeportPkwyAnd8901EstersBoulevardIrvingTXMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">8675,8701-8711 Freeport Pkwy and 8901 Esters Boulevard, Irving, TX</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A867587018711FreeportPkwyAnd8901EstersBoulevardIrvingTXMember" xlink:href="opi-20251231.xsd#opi_A867587018711FreeportPkwyAnd8901EstersBoulevardIrvingTXMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A867587018711FreeportPkwyAnd8901EstersBoulevardIrvingTXMember" xlink:to="lab_opi_A867587018711FreeportPkwyAnd8901EstersBoulevardIrvingTXMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_019dbc7a-b1cb-7a19-be10-2ca9116f06ce_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Required Principal Payments</link:label>
    <link:label id="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Maturities of Long-Term Debt [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_Revenues_019dbc7a-b286-72ce-99f8-181ad5095f19_terseLabel_en-US" xlink:label="lab_us-gaap_Revenues" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rental income</link:label>
    <link:label id="lab_us-gaap_Revenues_label_en-US" xlink:label="lab_us-gaap_Revenues" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenues</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Revenues"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Revenues" xlink:to="lab_us-gaap_Revenues" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_FrValAsOfPrrYrEndOfEqtyAwrdsGrntdInPrrYrsFldVstngCondsDrngCvrdYrMember_terseLabel_en-US" xlink:label="lab_ecd_FrValAsOfPrrYrEndOfEqtyAwrdsGrntdInPrrYrsFldVstngCondsDrngCvrdYrMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year</link:label>
    <link:label id="lab_ecd_FrValAsOfPrrYrEndOfEqtyAwrdsGrntdInPrrYrsFldVstngCondsDrngCvrdYrMember_label_en-US" xlink:label="lab_ecd_FrValAsOfPrrYrEndOfEqtyAwrdsGrntdInPrrYrsFldVstngCondsDrngCvrdYrMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_FrValAsOfPrrYrEndOfEqtyAwrdsGrntdInPrrYrsFldVstngCondsDrngCvrdYrMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_FrValAsOfPrrYrEndOfEqtyAwrdsGrntdInPrrYrsFldVstngCondsDrngCvrdYrMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_FrValAsOfPrrYrEndOfEqtyAwrdsGrntdInPrrYrsFldVstngCondsDrngCvrdYrMember" xlink:to="lab_ecd_FrValAsOfPrrYrEndOfEqtyAwrdsGrntdInPrrYrsFldVstngCondsDrngCvrdYrMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019dbc7a-b287-7e8e-8b68-006222e26e17_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair Value of Financial Instruments</link:label>
    <link:label id="lab_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_label_en-US" xlink:label="lab_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:to="lab_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_OutstandingAggtErrCompAmt_terseLabel_en-US" xlink:label="lab_ecd_OutstandingAggtErrCompAmt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Outstanding Aggregate Erroneous Compensation Amount</link:label>
    <link:label id="lab_ecd_OutstandingAggtErrCompAmt_label_en-US" xlink:label="lab_ecd_OutstandingAggtErrCompAmt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Outstanding Aggregate Erroneous Compensation Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_OutstandingAggtErrCompAmt" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_OutstandingAggtErrCompAmt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_OutstandingAggtErrCompAmt" xlink:to="lab_ecd_OutstandingAggtErrCompAmt" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_AmendedAndRestateBusinessManagementAgreementMember_019dbc7a-b287-7ca4-9adc-655618606e80_terseLabel_en-US" xlink:label="lab_opi_AmendedAndRestateBusinessManagementAgreementMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amended And Restate Business Management Agreement</link:label>
    <link:label id="lab_opi_AmendedAndRestateBusinessManagementAgreementMember_label_en-US" xlink:label="lab_opi_AmendedAndRestateBusinessManagementAgreementMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amended And Restate Business Management Agreement [Member]</link:label>
    <link:label id="lab_opi_AmendedAndRestateBusinessManagementAgreementMember_documentation_en-US" xlink:label="lab_opi_AmendedAndRestateBusinessManagementAgreementMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents information pertaining to the amended and restated business management agreement.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_AmendedAndRestateBusinessManagementAgreementMember" xlink:href="opi-20251231.xsd#opi_AmendedAndRestateBusinessManagementAgreementMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_AmendedAndRestateBusinessManagementAgreementMember" xlink:to="lab_opi_AmendedAndRestateBusinessManagementAgreementMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RealEstateAggregateSalesPrice_019dbc7a-b1cb-788f-8c79-57f0cbdd3477_terseLabel_en-US" xlink:label="lab_opi_RealEstateAggregateSalesPrice" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gross Sales Price</link:label>
    <link:label id="lab_opi_RealEstateAggregateSalesPrice_label_en-US" xlink:label="lab_opi_RealEstateAggregateSalesPrice" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Aggregate Sales Price</link:label>
    <link:label id="lab_opi_RealEstateAggregateSalesPrice_documentation_en-US" xlink:label="lab_opi_RealEstateAggregateSalesPrice" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents the aggregate sales price excluding closing costs, of real estate properties sold by the entity.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RealEstateAggregateSalesPrice" xlink:href="opi-20251231.xsd#opi_RealEstateAggregateSalesPrice"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RealEstateAggregateSalesPrice" xlink:to="lab_opi_RealEstateAggregateSalesPrice" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationAwardTrancheOneMember_019dbc7a-b1cb-7eb6-a0c9-ed7d7f7fa5a0_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationAwardTrancheOneMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement, Tranche 1</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationAwardTrancheOneMember_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationAwardTrancheOneMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement, Tranche One [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationAwardTrancheOneMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationAwardTrancheOneMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationAwardTrancheOneMember" xlink:to="lab_us-gaap_ShareBasedCompensationAwardTrancheOneMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A20012003CommerceParkDriveAnnapolisMDMember_019dbc7a-b287-703e-b593-bd68089cda79_terseLabel_en-US" xlink:label="lab_opi_A20012003CommerceParkDriveAnnapolisMDMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2001-2003 Commerce Park Drive, Annapolis, MD</link:label>
    <link:label id="lab_opi_A20012003CommerceParkDriveAnnapolisMDMember_label_en-US" xlink:label="lab_opi_A20012003CommerceParkDriveAnnapolisMDMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2001-2003 Commerce Park Drive, Annapolis, MD [Member]</link:label>
    <link:label id="lab_opi_A20012003CommerceParkDriveAnnapolisMDMember_documentation_en-US" xlink:label="lab_opi_A20012003CommerceParkDriveAnnapolisMDMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2001-2003 Commerce Park Drive, Annapolis, MD</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A20012003CommerceParkDriveAnnapolisMDMember" xlink:href="opi-20251231.xsd#opi_A20012003CommerceParkDriveAnnapolisMDMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A20012003CommerceParkDriveAnnapolisMDMember" xlink:to="lab_opi_A20012003CommerceParkDriveAnnapolisMDMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AwardExrcPrice_terseLabel_en-US" xlink:label="lab_ecd_AwardExrcPrice" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Exercise Price</link:label>
    <link:label id="lab_ecd_AwardExrcPrice_label_en-US" xlink:label="lab_ecd_AwardExrcPrice" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Award Exercise Price</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AwardExrcPrice" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AwardExrcPrice"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AwardExrcPrice" xlink:to="lab_ecd_AwardExrcPrice" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfAverageMarketCapitalization_019dbc7a-b287-72b8-b01e-39376ea8ea6a_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfAverageMarketCapitalization" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Threshold amount of average market capitalization</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfAverageMarketCapitalization_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfAverageMarketCapitalization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction Base Management Fee Payable Threshold Amount of Average Market Capitalization</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfAverageMarketCapitalization_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfAverageMarketCapitalization" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the threshold amount of average market capitalization for payment of the base management fee.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfAverageMarketCapitalization" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfAverageMarketCapitalization"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfAverageMarketCapitalization" xlink:to="lab_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfAverageMarketCapitalization" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityFilerCategory_019dbc7a-b1cb-7be0-a292-329663e84091_terseLabel_en-US" xlink:label="lab_dei_EntityFilerCategory" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Filer Category</link:label>
    <link:label id="lab_dei_EntityFilerCategory_label_en-US" xlink:label="lab_dei_EntityFilerCategory" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Filer Category</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityFilerCategory"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityFilerCategory" xlink:to="lab_dei_EntityFilerCategory" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SubsequentEventTypeAxis_019dbc7a-b286-7363-9607-e74b49245d8d_terseLabel_en-US" xlink:label="lab_us-gaap_SubsequentEventTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Subsequent Event Type [Axis]</link:label>
    <link:label id="lab_us-gaap_SubsequentEventTypeAxis_label_en-US" xlink:label="lab_us-gaap_SubsequentEventTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Subsequent Event Type [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsequentEventTypeAxis" xlink:to="lab_us-gaap_SubsequentEventTypeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NonrelatedPartyMember_019dbc7a-b286-7de8-baf1-954db17a9fd9_terseLabel_en-US" xlink:label="lab_us-gaap_NonrelatedPartyMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Nonrelated Party</link:label>
    <link:label id="lab_us-gaap_NonrelatedPartyMember_label_en-US" xlink:label="lab_us-gaap_NonrelatedPartyMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Nonrelated Party [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonrelatedPartyMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NonrelatedPartyMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NonrelatedPartyMember" xlink:to="lab_us-gaap_NonrelatedPartyMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_019dbc7a-b286-7552-b597-f67fae998255_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2027</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Asset, Expected Amortization, Year Three</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityAddressAddressLine3_019dbc7a-b1cb-7c8d-8874-0f436085fabe_terseLabel_en-US" xlink:label="lab_dei_EntityAddressAddressLine3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Address, Address Line Three</link:label>
    <link:label id="lab_dei_EntityAddressAddressLine3_label_en-US" xlink:label="lab_dei_EntityAddressAddressLine3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Address, Address Line Three</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine3" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine3"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressAddressLine3" xlink:to="lab_dei_EntityAddressAddressLine3" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_VestingDomain_019dbc7a-b1cb-7e2b-8f68-5a1562878cef_terseLabel_en-US" xlink:label="lab_us-gaap_VestingDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vesting [Domain]</link:label>
    <link:label id="lab_us-gaap_VestingDomain_label_en-US" xlink:label="lab_us-gaap_VestingDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Vesting [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VestingDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VestingDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_VestingDomain" xlink:to="lab_us-gaap_VestingDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsGross_019dbc7a-b287-7f40-bc47-d51ef4e590bb_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real estate leases</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsGross_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsGross" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsGross" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_VstngDtFrValOfEqtyAwrdsGrntdAndVstdInCvrdYrMember_terseLabel_en-US" xlink:label="lab_ecd_VstngDtFrValOfEqtyAwrdsGrntdAndVstdInCvrdYrMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year</link:label>
    <link:label id="lab_ecd_VstngDtFrValOfEqtyAwrdsGrntdAndVstdInCvrdYrMember_label_en-US" xlink:label="lab_ecd_VstngDtFrValOfEqtyAwrdsGrntdAndVstdInCvrdYrMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_VstngDtFrValOfEqtyAwrdsGrntdAndVstdInCvrdYrMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_VstngDtFrValOfEqtyAwrdsGrntdAndVstdInCvrdYrMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_VstngDtFrValOfEqtyAwrdsGrntdAndVstdInCvrdYrMember" xlink:to="lab_ecd_VstngDtFrValOfEqtyAwrdsGrntdAndVstdInCvrdYrMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RocklinCAMember_019dbc7a-b286-7601-8bc7-9960e15b8193_terseLabel_en-US" xlink:label="lab_opi_RocklinCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rocklin, CA</link:label>
    <link:label id="lab_opi_RocklinCAMember_label_en-US" xlink:label="lab_opi_RocklinCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Rocklin, CA [Member]</link:label>
    <link:label id="lab_opi_RocklinCAMember_documentation_en-US" xlink:label="lab_opi_RocklinCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Rocklin, CA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RocklinCAMember" xlink:href="opi-20251231.xsd#opi_RocklinCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RocklinCAMember" xlink:to="lab_opi_RocklinCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A603SanJuanAvenueStocktonCAMember_019dbc7a-b287-7d7c-9149-fa37c47d881b_terseLabel_en-US" xlink:label="lab_opi_A603SanJuanAvenueStocktonCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">603 San Juan Avenue, Stockton, CA</link:label>
    <link:label id="lab_opi_A603SanJuanAvenueStocktonCAMember_label_en-US" xlink:label="lab_opi_A603SanJuanAvenueStocktonCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">603 San Juan Avenue, Stockton, CA [Member]</link:label>
    <link:label id="lab_opi_A603SanJuanAvenueStocktonCAMember_documentation_en-US" xlink:label="lab_opi_A603SanJuanAvenueStocktonCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">603 San Juan Avenue, Stockton, CA [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A603SanJuanAvenueStocktonCAMember" xlink:href="opi-20251231.xsd#opi_A603SanJuanAvenueStocktonCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A603SanJuanAvenueStocktonCAMember" xlink:to="lab_opi_A603SanJuanAvenueStocktonCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionPriorityReturnIncreasePercentOfCapitalExpenditures_019dbc7a-b287-70f0-be43-4703b8c3ec5c_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionPriorityReturnIncreasePercentOfCapitalExpenditures" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Priority return increase percentage of out-of-pocket capital expenditures</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionPriorityReturnIncreasePercentOfCapitalExpenditures_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionPriorityReturnIncreasePercentOfCapitalExpenditures" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Priority Return Increase, Percent Of Capital Expenditures</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionPriorityReturnIncreasePercentOfCapitalExpenditures_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionPriorityReturnIncreasePercentOfCapitalExpenditures" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Priority Return Increase, Percent Of Capital Expenditures</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionPriorityReturnIncreasePercentOfCapitalExpenditures" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionPriorityReturnIncreasePercentOfCapitalExpenditures"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionPriorityReturnIncreasePercentOfCapitalExpenditures" xlink:to="lab_opi_RelatedPartyTransactionPriorityReturnIncreasePercentOfCapitalExpenditures" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityAddressAddressLine1_019dbc7a-b286-7d98-a6ac-323e567be59e_terseLabel_en-US" xlink:label="lab_dei_EntityAddressAddressLine1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Address, Address Line One</link:label>
    <link:label id="lab_dei_EntityAddressAddressLine1_label_en-US" xlink:label="lab_dei_EntityAddressAddressLine1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Address, Address Line One</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressAddressLine1" xlink:to="lab_dei_EntityAddressAddressLine1" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityAddressAddressLine2_019dbc7a-b286-784b-bc0e-3330d33b99f7_terseLabel_en-US" xlink:label="lab_dei_EntityAddressAddressLine2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Address, Address Line Two</link:label>
    <link:label id="lab_dei_EntityAddressAddressLine2_label_en-US" xlink:label="lab_dei_EntityAddressAddressLine2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Address, Address Line Two</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine2" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine2"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressAddressLine2" xlink:to="lab_dei_EntityAddressAddressLine2" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwelve_019dbc7a-b287-7dd1-85f2-585a4e1f83f5_terseLabel_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwelve" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2037</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwelve_label_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwelve" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right Exercisable In Year Twelve</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwelve_documentation_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwelve" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right Exercisable In Year Twelve</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwelve" xlink:href="opi-20251231.xsd#opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwelve"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwelve" xlink:to="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwelve" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodAreaOfLeasedProperty_019dbc7a-b286-7368-8bb4-0a0f51811b7e_terseLabel_en-US" xlink:label="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodAreaOfLeasedProperty" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rentable square feet (in square feet)</link:label>
    <link:label id="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodAreaOfLeasedProperty_label_en-US" xlink:label="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodAreaOfLeasedProperty" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Leases Committed Expenditures on Leases Executed in Period Area of Leased Property</link:label>
    <link:label id="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodAreaOfLeasedProperty_documentation_en-US" xlink:label="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodAreaOfLeasedProperty" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the area of leased property related to operating leases executed during the period.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodAreaOfLeasedProperty" xlink:href="opi-20251231.xsd#opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodAreaOfLeasedProperty"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodAreaOfLeasedProperty" xlink:to="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodAreaOfLeasedProperty" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredChargesPolicyTextBlock_019dbc7a-b286-7812-97f9-1fdd0f809d34_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredChargesPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred Leasing Costs</link:label>
    <link:label id="lab_us-gaap_DeferredChargesPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_DeferredChargesPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Charges, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredChargesPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredChargesPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredChargesPolicyTextBlock" xlink:to="lab_us-gaap_DeferredChargesPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfRealEstatePropertiesTableTextBlock_019dbc7a-b1cb-7a9d-9835-0be78b7c569b_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfRealEstatePropertiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Real Estate Properties</link:label>
    <link:label id="lab_us-gaap_ScheduleOfRealEstatePropertiesTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfRealEstatePropertiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Real Estate Properties [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRealEstatePropertiesTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfRealEstatePropertiesTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfRealEstatePropertiesTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfRealEstatePropertiesTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019dbc7a-b1cb-756c-b25e-ad51ee057213_terseLabel_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Name of Property [Domain]</link:label>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_label_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Name of Property [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain" xlink:to="lab_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AwardGrantDateFairValue_terseLabel_en-US" xlink:label="lab_ecd_AwardGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair Value as of Grant Date</link:label>
    <link:label id="lab_ecd_AwardGrantDateFairValue_label_en-US" xlink:label="lab_ecd_AwardGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Award Grant Date Fair Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AwardGrantDateFairValue" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AwardGrantDateFairValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AwardGrantDateFairValue" xlink:to="lab_ecd_AwardGrantDateFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LessorOperatingLeasePaymentToBeReceivedMember_019dbc7a-b1cb-7658-a23c-0cf01a7cfc5b_terseLabel_en-US" xlink:label="lab_opi_LessorOperatingLeasePaymentToBeReceivedMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received</link:label>
    <link:label id="lab_opi_LessorOperatingLeasePaymentToBeReceivedMember_label_en-US" xlink:label="lab_opi_LessorOperatingLeasePaymentToBeReceivedMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment To Be Received [Member]</link:label>
    <link:label id="lab_opi_LessorOperatingLeasePaymentToBeReceivedMember_documentation_en-US" xlink:label="lab_opi_LessorOperatingLeasePaymentToBeReceivedMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment To Be Received</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LessorOperatingLeasePaymentToBeReceivedMember" xlink:href="opi-20251231.xsd#opi_LessorOperatingLeasePaymentToBeReceivedMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LessorOperatingLeasePaymentToBeReceivedMember" xlink:to="lab_opi_LessorOperatingLeasePaymentToBeReceivedMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfDebtInstrumentsTextBlock_019dbc7a-b287-7607-867e-a3b217a0834e_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfDebtInstrumentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Long-Term Debt Instruments</link:label>
    <link:label id="lab_us-gaap_ScheduleOfDebtInstrumentsTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfDebtInstrumentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Long-Term Debt Instruments [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDebtInstrumentsTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDebtInstrumentsTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfDebtInstrumentsTextBlock" xlink:to="lab_us-gaap_ScheduleOfDebtInstrumentsTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019dbc7a-b287-7039-aaba-8e4a2260ef3e_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Shares granted (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019dbc7a-b287-71bc-9e98-d50ac1def306_verboseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Granted (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SECScheduleIIIRealEstateWritedownOrReserveAmount_019dbc7a-b287-7d89-ad9a-741895a78ff7_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_SECScheduleIIIRealEstateWritedownOrReserveAmount" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Loss on asset impairment</link:label>
    <link:label id="lab_us-gaap_SECScheduleIIIRealEstateWritedownOrReserveAmount_label_en-US" xlink:label="lab_us-gaap_SECScheduleIIIRealEstateWritedownOrReserveAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Write-down or Reserve, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SECScheduleIIIRealEstateWritedownOrReserveAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SECScheduleIIIRealEstateWritedownOrReserveAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SECScheduleIIIRealEstateWritedownOrReserveAmount" xlink:to="lab_us-gaap_SECScheduleIIIRealEstateWritedownOrReserveAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_TitleOfIndividualWithRelationshipToEntityDomain_019dbc7a-b1cb-7bd0-bd74-a4679149d48f_terseLabel_en-US" xlink:label="lab_srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Title and Position [Domain]</link:label>
    <link:label id="lab_srt_TitleOfIndividualWithRelationshipToEntityDomain_label_en-US" xlink:label="lab_srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Title and Position [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="lab_srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CostsAndExpenses_019dbc7a-b287-7fe8-a36e-d508d7d2cef7_totalLabel_en-US" xlink:label="lab_us-gaap_CostsAndExpenses" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total expenses</link:label>
    <link:label id="lab_us-gaap_CostsAndExpenses_label_en-US" xlink:label="lab_us-gaap_CostsAndExpenses" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Costs and Expenses</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostsAndExpenses"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CostsAndExpenses" xlink:to="lab_us-gaap_CostsAndExpenses" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_019dbc7a-b286-7ffb-8c2a-cf6211b2828c_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Forfeited (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_019dbc7a-b30c-7ddb-bb93-2f8aef3c77b3_terseLabel_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Estimated future compensation expense for the unvested shares</link:label>
    <link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_label_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:to="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RelatedPartyTransactionLineItems_019dbc7a-b286-759b-9bb9-a2d0af942c2e_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Related Party Transaction [Line Items]</link:label>
    <link:label id="lab_us-gaap_RelatedPartyTransactionLineItems_label_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems" xlink:to="lab_us-gaap_RelatedPartyTransactionLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtFairValue_019dbc7a-b287-7e8d-80e5-3a24c92bc9bc_totalLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtFairValue" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total</link:label>
    <link:label id="lab_us-gaap_LongTermDebtFairValue_label_en-US" xlink:label="lab_us-gaap_LongTermDebtFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Fair Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtFairValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtFairValue" xlink:to="lab_us-gaap_LongTermDebtFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_ChangedPeerGroupFnTextBlock_terseLabel_en-US" xlink:label="lab_ecd_ChangedPeerGroupFnTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Changed Peer Group, Footnote</link:label>
    <link:label id="lab_ecd_ChangedPeerGroupFnTextBlock_label_en-US" xlink:label="lab_ecd_ChangedPeerGroupFnTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Changed Peer Group, Footnote [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_ChangedPeerGroupFnTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_ChangedPeerGroupFnTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_ChangedPeerGroupFnTextBlock" xlink:to="lab_ecd_ChangedPeerGroupFnTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RepurchaseAgreementCounterpartyNameDomain_019dbc7a-b286-7d44-9d29-8c551d6d0a1f_terseLabel_en-US" xlink:label="lab_srt_RepurchaseAgreementCounterpartyNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Counterparty Name [Domain]</link:label>
    <link:label id="lab_srt_RepurchaseAgreementCounterpartyNameDomain_label_en-US" xlink:label="lab_srt_RepurchaseAgreementCounterpartyNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Counterparty Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain" xlink:to="lab_srt_RepurchaseAgreementCounterpartyNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageThresholdReductionInPercentageFee_019dbc7a-b286-7baa-88e3-910c9fd585dd_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageThresholdReductionInPercentageFee" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage for limitation and adjustments of incentive management fee payable, total return per share percentage, reduction</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageThresholdReductionInPercentageFee_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageThresholdReductionInPercentageFee" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Percentage For Limitation And Adjustments Of Incentive Management Fee Payable, Percentage Threshold Reduction In Percentage Fee</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageThresholdReductionInPercentageFee_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageThresholdReductionInPercentageFee" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Percentage For Limitation And Adjustments Of Incentive Management Fee Payable, Percentage Threshold For Per Share, Reduction In Percentage Fee</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageThresholdReductionInPercentageFee" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageThresholdReductionInPercentageFee"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageThresholdReductionInPercentageFee" xlink:to="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayablePercentageThresholdReductionInPercentageFee" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DetroitMIMember_019dbc7a-b1cb-78e7-8cb8-2779eb991865_terseLabel_en-US" xlink:label="lab_opi_DetroitMIMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Detroit, MI</link:label>
    <link:label id="lab_opi_DetroitMIMember_label_en-US" xlink:label="lab_opi_DetroitMIMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Detroit, MI [Member]</link:label>
    <link:label id="lab_opi_DetroitMIMember_documentation_en-US" xlink:label="lab_opi_DetroitMIMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Detroit, MI</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DetroitMIMember" xlink:href="opi-20251231.xsd#opi_DetroitMIMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DetroitMIMember" xlink:to="lab_opi_DetroitMIMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AdjToPeoCompFnTextBlock_terseLabel_en-US" xlink:label="lab_ecd_AdjToPeoCompFnTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Adjustment To PEO Compensation, Footnote</link:label>
    <link:label id="lab_ecd_AdjToPeoCompFnTextBlock_label_en-US" xlink:label="lab_ecd_AdjToPeoCompFnTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Adjustment To PEO Compensation, Footnote [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AdjToPeoCompFnTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AdjToPeoCompFnTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AdjToPeoCompFnTextBlock" xlink:to="lab_ecd_AdjToPeoCompFnTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A9815GoetheRoadSacramentoCAMember_019dbc7a-b287-7584-b28f-dd96ab16bcde_terseLabel_en-US" xlink:label="lab_opi_A9815GoetheRoadSacramentoCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">9815 Goethe Road, Sacramento, CA</link:label>
    <link:label id="lab_opi_A9815GoetheRoadSacramentoCAMember_label_en-US" xlink:label="lab_opi_A9815GoetheRoadSacramentoCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">9815 Goethe Road, Sacramento, CA [Member]</link:label>
    <link:label id="lab_opi_A9815GoetheRoadSacramentoCAMember_documentation_en-US" xlink:label="lab_opi_A9815GoetheRoadSacramentoCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">9815 Goethe Road, Sacramento, CA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A9815GoetheRoadSacramentoCAMember" xlink:href="opi-20251231.xsd#opi_A9815GoetheRoadSacramentoCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A9815GoetheRoadSacramentoCAMember" xlink:to="lab_opi_A9815GoetheRoadSacramentoCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_TrdArrIndTitle_terseLabel_en-US" xlink:label="lab_ecd_TrdArrIndTitle" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Title</link:label>
    <link:label id="lab_ecd_TrdArrIndTitle_label_en-US" xlink:label="lab_ecd_TrdArrIndTitle" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Trading Arrangement, Individual Title</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_TrdArrIndTitle" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_TrdArrIndTitle"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_TrdArrIndTitle" xlink:to="lab_ecd_TrdArrIndTitle" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_PeerGroupTotalShareholderRtnAmt_terseLabel_en-US" xlink:label="lab_ecd_PeerGroupTotalShareholderRtnAmt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Peer Group Total Shareholder Return Amount</link:label>
    <link:label id="lab_ecd_PeerGroupTotalShareholderRtnAmt_label_en-US" xlink:label="lab_ecd_PeerGroupTotalShareholderRtnAmt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Peer Group Total Shareholder Return Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_PeerGroupTotalShareholderRtnAmt" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_PeerGroupTotalShareholderRtnAmt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_PeerGroupTotalShareholderRtnAmt" xlink:to="lab_ecd_PeerGroupTotalShareholderRtnAmt" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_NonPeoNeoMember_terseLabel_en-US" xlink:label="lab_ecd_NonPeoNeoMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Non-PEO NEO</link:label>
    <link:label id="lab_ecd_NonPeoNeoMember_label_en-US" xlink:label="lab_ecd_NonPeoNeoMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Non-PEO NEO [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_NonPeoNeoMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_NonPeoNeoMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_NonPeoNeoMember" xlink:to="lab_ecd_NonPeoNeoMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SubsidiarySaleOfStockAxis_019dbc7a-b1cb-7df4-b520-d6d7e18dcadb_terseLabel_en-US" xlink:label="lab_us-gaap_SubsidiarySaleOfStockAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sale of Stock [Axis]</link:label>
    <link:label id="lab_us-gaap_SubsidiarySaleOfStockAxis_label_en-US" xlink:label="lab_us-gaap_SubsidiarySaleOfStockAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale of Stock [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis" xlink:to="lab_us-gaap_SubsidiarySaleOfStockAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">All Award Types</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Award Type [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LiabilitiesSubjectToCompromiseDebt_019dd0ba-400b-7fd4-a0fd-fa3d8d5d197b_terseLabel_en-US" xlink:label="lab_opi_LiabilitiesSubjectToCompromiseDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt</link:label>
    <link:label id="lab_opi_LiabilitiesSubjectToCompromiseDebt_label_en-US" xlink:label="lab_opi_LiabilitiesSubjectToCompromiseDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities Subject To Compromise, Debt</link:label>
    <link:label id="lab_opi_LiabilitiesSubjectToCompromiseDebt_documentation_en-US" xlink:label="lab_opi_LiabilitiesSubjectToCompromiseDebt" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Liabilities Subject to Compromise, Debt</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LiabilitiesSubjectToCompromiseDebt" xlink:href="opi-20251231.xsd#opi_LiabilitiesSubjectToCompromiseDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LiabilitiesSubjectToCompromiseDebt" xlink:to="lab_opi_LiabilitiesSubjectToCompromiseDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_EqtyAwrdsAdjsMember_terseLabel_en-US" xlink:label="lab_ecd_EqtyAwrdsAdjsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity Awards Adjustments</link:label>
    <link:label id="lab_ecd_EqtyAwrdsAdjsMember_label_en-US" xlink:label="lab_ecd_EqtyAwrdsAdjsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Awards Adjustments [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_EqtyAwrdsAdjsMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_EqtyAwrdsAdjsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_EqtyAwrdsAdjsMember" xlink:to="lab_ecd_EqtyAwrdsAdjsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherNoncashIncomeExpense_019dbc86-f969-7460-aca9-a5e7e93da233_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_OtherNoncashIncomeExpense" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Other non-cash expenses, net</link:label>
    <link:label id="lab_us-gaap_OtherNoncashIncomeExpense_label_en-US" xlink:label="lab_us-gaap_OtherNoncashIncomeExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Noncash Income (Expense)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncashIncomeExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNoncashIncomeExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherNoncashIncomeExpense" xlink:to="lab_us-gaap_OtherNoncashIncomeExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_PnsnBnftsAdjFnTextBlock_terseLabel_en-US" xlink:label="lab_ecd_PnsnBnftsAdjFnTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pension Benefits Adjustments, Footnote</link:label>
    <link:label id="lab_ecd_PnsnBnftsAdjFnTextBlock_label_en-US" xlink:label="lab_ecd_PnsnBnftsAdjFnTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pension Benefits Adjustments, Footnote [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_PnsnBnftsAdjFnTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_PnsnBnftsAdjFnTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_PnsnBnftsAdjFnTextBlock" xlink:to="lab_ecd_PnsnBnftsAdjFnTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionAnnualFee_019dd5f9-b2c8-734d-9784-bdeeff254769_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionAnnualFee" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Annual fee under agreement</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionAnnualFee_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionAnnualFee" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Annual Fee</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionAnnualFee_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionAnnualFee" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Annual Fee</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionAnnualFee" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionAnnualFee"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionAnnualFee" xlink:to="lab_opi_RelatedPartyTransactionAnnualFee" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_OutstandingRecoveryCompAmt_terseLabel_en-US" xlink:label="lab_ecd_OutstandingRecoveryCompAmt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Compensation Amount</link:label>
    <link:label id="lab_ecd_OutstandingRecoveryCompAmt_label_en-US" xlink:label="lab_ecd_OutstandingRecoveryCompAmt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Outstanding Recovery Compensation Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_OutstandingRecoveryCompAmt" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_OutstandingRecoveryCompAmt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_OutstandingRecoveryCompAmt" xlink:to="lab_ecd_OutstandingRecoveryCompAmt" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A20092011CommerceParkDriveAnnapolisMDMember_019dbc7a-b1cb-7a09-ac1c-0718f9ce0846_terseLabel_en-US" xlink:label="lab_opi_A20092011CommerceParkDriveAnnapolisMDMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2009-2011 Commerce Park Drive, Annapolis, MD</link:label>
    <link:label id="lab_opi_A20092011CommerceParkDriveAnnapolisMDMember_label_en-US" xlink:label="lab_opi_A20092011CommerceParkDriveAnnapolisMDMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2009-2011 Commerce Park Drive, Annapolis, MD [Member]</link:label>
    <link:label id="lab_opi_A20092011CommerceParkDriveAnnapolisMDMember_documentation_en-US" xlink:label="lab_opi_A20092011CommerceParkDriveAnnapolisMDMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2009-2011 Commerce Park Drive, Annapolis, MD</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A20092011CommerceParkDriveAnnapolisMDMember" xlink:href="opi-20251231.xsd#opi_A20092011CommerceParkDriveAnnapolisMDMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A20092011CommerceParkDriveAnnapolisMDMember" xlink:to="lab_opi_A20092011CommerceParkDriveAnnapolisMDMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentNameDomain_019dbc7a-b1cb-7f9a-8b83-4af8b5196b43_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Instrument, Name [Domain]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentNameDomain_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentNameDomain" xlink:to="lab_us-gaap_DebtInstrumentNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_OrbitalSciencesCampusSterlingVAMember_019dbc7a-b286-788d-a545-4a8f1b7da613_terseLabel_en-US" xlink:label="lab_opi_OrbitalSciencesCampusSterlingVAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Orbital Sciences Campus, Sterling, VA</link:label>
    <link:label id="lab_opi_OrbitalSciencesCampusSterlingVAMember_label_en-US" xlink:label="lab_opi_OrbitalSciencesCampusSterlingVAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Orbital Sciences Campus, Sterling, VA [Member]</link:label>
    <link:label id="lab_opi_OrbitalSciencesCampusSterlingVAMember_documentation_en-US" xlink:label="lab_opi_OrbitalSciencesCampusSterlingVAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Orbital Sciences Campus, Sterling, VA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_OrbitalSciencesCampusSterlingVAMember" xlink:href="opi-20251231.xsd#opi_OrbitalSciencesCampusSterlingVAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_OrbitalSciencesCampusSterlingVAMember" xlink:to="lab_opi_OrbitalSciencesCampusSterlingVAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateDisclosureTextBlock_019dbc7a-b286-735e-a799-cdaaa6d14ddb_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate Properties</link:label>
    <link:label id="lab_us-gaap_RealEstateDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_RealEstateDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateDisclosureTextBlock" xlink:to="lab_us-gaap_RealEstateDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StraightLineRent_019dbc86-ec84-71d4-918c-7df98e0a453f_negatedLabel_en-US" xlink:label="lab_us-gaap_StraightLineRent" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Straight line rental income</link:label>
    <link:label id="lab_us-gaap_StraightLineRent_019dd08b-aaa8-7597-ae59-2b87a7c1138e_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_StraightLineRent" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Straight Line Rent</link:label>
    <link:label id="lab_us-gaap_StraightLineRent_label_en-US" xlink:label="lab_us-gaap_StraightLineRent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Straight Line Rent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StraightLineRent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StraightLineRent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StraightLineRent" xlink:to="lab_us-gaap_StraightLineRent" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_RecoveryOfErrCompDisclosureLineItems_label_en-US" xlink:label="lab_ecd_RecoveryOfErrCompDisclosureLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Recovery of Erroneously Awarded Compensation Disclosure [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_RecoveryOfErrCompDisclosureLineItems" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_RecoveryOfErrCompDisclosureLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_RecoveryOfErrCompDisclosureLineItems" xlink:to="lab_ecd_RecoveryOfErrCompDisclosureLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EstimateOfFairValueFairValueDisclosureMember_019dbc7a-b1cb-7641-8964-849102e947dd_terseLabel_en-US" xlink:label="lab_us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair&#160;Value</link:label>
    <link:label id="lab_us-gaap_EstimateOfFairValueFairValueDisclosureMember_label_en-US" xlink:label="lab_us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Estimate of Fair Value Measurement [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:to="lab_us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_VariableLeaseIncome_019dbc7a-b287-7aae-a8b1-c27c042fbdd9_terseLabel_en-US" xlink:label="lab_us-gaap_VariableLeaseIncome" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Variable lease, income</link:label>
    <link:label id="lab_us-gaap_VariableLeaseIncome_label_en-US" xlink:label="lab_us-gaap_VariableLeaseIncome" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Variable Lease, Income</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableLeaseIncome" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableLeaseIncome"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_VariableLeaseIncome" xlink:to="lab_us-gaap_VariableLeaseIncome" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_MnpiDiscTimedForCompValFlag_terseLabel_en-US" xlink:label="lab_ecd_MnpiDiscTimedForCompValFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">MNPI Disclosure Timed for Compensation Value</link:label>
    <link:label id="lab_ecd_MnpiDiscTimedForCompValFlag_label_en-US" xlink:label="lab_ecd_MnpiDiscTimedForCompValFlag" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">MNPI Disclosure Timed for Compensation Value [Flag]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_MnpiDiscTimedForCompValFlag" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_MnpiDiscTimedForCompValFlag"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_MnpiDiscTimedForCompValFlag" xlink:to="lab_ecd_MnpiDiscTimedForCompValFlag" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A8.375SeniorSecuredNotesMember_019dff17-d7be-7cc2-babe-6b903389b2bf_terseLabel_en-US" xlink:label="lab_opi_A8.375SeniorSecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">8.375% Senior Secured Notes</link:label>
    <link:label id="lab_opi_A8.375SeniorSecuredNotesMember_label_en-US" xlink:label="lab_opi_A8.375SeniorSecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">8.375% Senior Secured Notes [Member]</link:label>
    <link:label id="lab_opi_A8.375SeniorSecuredNotesMember_documentation_en-US" xlink:label="lab_opi_A8.375SeniorSecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">8.375% Senior Secured Notes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A8.375SeniorSecuredNotesMember" xlink:href="opi-20251231.xsd#opi_A8.375SeniorSecuredNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A8.375SeniorSecuredNotesMember" xlink:to="lab_opi_A8.375SeniorSecuredNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentsIncorporatedByReferenceTextBlock_019dbc7a-b1cb-741f-b375-0d22597438c1_terseLabel_en-US" xlink:label="lab_dei_DocumentsIncorporatedByReferenceTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Documents Incorporated by Reference</link:label>
    <link:label id="lab_dei_DocumentsIncorporatedByReferenceTextBlock_label_en-US" xlink:label="lab_dei_DocumentsIncorporatedByReferenceTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Documents Incorporated by Reference [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentsIncorporatedByReferenceTextBlock" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentsIncorporatedByReferenceTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentsIncorporatedByReferenceTextBlock" xlink:to="lab_dei_DocumentsIncorporatedByReferenceTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A7305MortgageNotesPayableMember_019dbcac-efcd-72ea-9143-fc003a4c7a78_terseLabel_en-US" xlink:label="lab_opi_A7305MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mortgage note payable, 7.305% interest rate, due in 2033</link:label>
    <link:label id="lab_opi_A7305MortgageNotesPayableMember_label_en-US" xlink:label="lab_opi_A7305MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">7.305% Mortgage Notes Payable [Member]</link:label>
    <link:label id="lab_opi_A7305MortgageNotesPayableMember_documentation_en-US" xlink:label="lab_opi_A7305MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">7.305% Mortgage Notes Payable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A7305MortgageNotesPayableMember" xlink:href="opi-20251231.xsd#opi_A7305MortgageNotesPayableMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A7305MortgageNotesPayableMember" xlink:to="lab_opi_A7305MortgageNotesPayableMember" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances_019dbc7a-b286-7ea1-b4ea-ce4d78f5dba1_terseLabel_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Encumbrances</link:label>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances_label_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Amount of Encumbrances</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances" xlink:to="lab_srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_StevensCenterRichlandWAMember_019dbc7a-b1cb-7635-8851-cc419e98331b_terseLabel_en-US" xlink:label="lab_opi_StevensCenterRichlandWAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stevens Center, Richland, WA</link:label>
    <link:label id="lab_opi_StevensCenterRichlandWAMember_label_en-US" xlink:label="lab_opi_StevensCenterRichlandWAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stevens Center, Richland, WA [Member]</link:label>
    <link:label id="lab_opi_StevensCenterRichlandWAMember_documentation_en-US" xlink:label="lab_opi_StevensCenterRichlandWAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Stevens Center [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_StevensCenterRichlandWAMember" xlink:href="opi-20251231.xsd#opi_StevensCenterRichlandWAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_StevensCenterRichlandWAMember" xlink:to="lab_opi_StevensCenterRichlandWAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_019dbc7a-b1cb-7938-b1a2-31eaeeb50c09_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2026</link:label>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Maturity, Year One</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_019dbc7a-b286-71b7-9ed1-4d802e246592_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2030</link:label>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Maturity, Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredCostsLeasingGross_019dbc7a-b1cb-7521-b382-235d253c2068_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredCostsLeasingGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred leasing costs, gross</link:label>
    <link:label id="lab_us-gaap_DeferredCostsLeasingGross_label_en-US" xlink:label="lab_us-gaap_DeferredCostsLeasingGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Costs, Leasing, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCostsLeasingGross" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredCostsLeasingGross"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredCostsLeasingGross" xlink:to="lab_us-gaap_DeferredCostsLeasingGross" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_OtherGeneralUnsecuredClaimsAmount_019e1849-b51e-7150-a462-a2e9fdc24182_terseLabel_en-US" xlink:label="lab_opi_OtherGeneralUnsecuredClaimsAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other general unsecured claims</link:label>
    <link:label id="lab_opi_OtherGeneralUnsecuredClaimsAmount_label_en-US" xlink:label="lab_opi_OtherGeneralUnsecuredClaimsAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other General Unsecured Claims, Amount</link:label>
    <link:label id="lab_opi_OtherGeneralUnsecuredClaimsAmount_documentation_en-US" xlink:label="lab_opi_OtherGeneralUnsecuredClaimsAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Other General Unsecured Claims, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_OtherGeneralUnsecuredClaimsAmount" xlink:href="opi-20251231.xsd#opi_OtherGeneralUnsecuredClaimsAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_OtherGeneralUnsecuredClaimsAmount" xlink:to="lab_opi_OtherGeneralUnsecuredClaimsAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AggtPnsnAdjsSvcCstMember_terseLabel_en-US" xlink:label="lab_ecd_AggtPnsnAdjsSvcCstMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate Pension Adjustments Service Cost</link:label>
    <link:label id="lab_ecd_AggtPnsnAdjsSvcCstMember_label_en-US" xlink:label="lab_ecd_AggtPnsnAdjsSvcCstMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Aggregate Pension Adjustments Service Cost [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AggtPnsnAdjsSvcCstMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AggtPnsnAdjsSvcCstMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AggtPnsnAdjsSvcCstMember" xlink:to="lab_ecd_AggtPnsnAdjsSvcCstMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019dbc7a-b287-7c8d-9c72-0b58df3a8d09_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets by Major Class [Axis]</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets by Major Class [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_MinimumMember_019dbc7a-b286-72cd-8931-cd505b84cc9c_terseLabel_en-US" xlink:label="lab_srt_MinimumMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Minimum</link:label>
    <link:label id="lab_srt_MinimumMember_label_en-US" xlink:label="lab_srt_MinimumMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Minimum [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_MinimumMember" xlink:to="lab_srt_MinimumMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherAmortizationOfDeferredCharges_019dbc86-092e-725c-8ed7-01b508083c8e_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAmortizationOfDeferredCharges" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amortization of deferred leasing costs</link:label>
    <link:label id="lab_us-gaap_OtherAmortizationOfDeferredCharges_label_en-US" xlink:label="lab_us-gaap_OtherAmortizationOfDeferredCharges" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amortization of Other Deferred Charges</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAmortizationOfDeferredCharges" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAmortizationOfDeferredCharges"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAmortizationOfDeferredCharges" xlink:to="lab_us-gaap_OtherAmortizationOfDeferredCharges" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateInvestmentsJointVentures_019dbc7a-b1cb-7b14-be20-0b32969a2eb3_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateInvestmentsJointVentures" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Investment in unconsolidated joint venture</link:label>
    <link:label id="lab_us-gaap_RealEstateInvestmentsJointVentures_label_en-US" xlink:label="lab_us-gaap_RealEstateInvestmentsJointVentures" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Investments, Joint Ventures</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentsJointVentures" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateInvestmentsJointVentures"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateInvestmentsJointVentures" xlink:to="lab_us-gaap_RealEstateInvestmentsJointVentures" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_CoSelectedMeasureName_terseLabel_en-US" xlink:label="lab_ecd_CoSelectedMeasureName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Company Selected Measure Name</link:label>
    <link:label id="lab_ecd_CoSelectedMeasureName_label_en-US" xlink:label="lab_ecd_CoSelectedMeasureName" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Company Selected Measure Name</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_CoSelectedMeasureName" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_CoSelectedMeasureName"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_CoSelectedMeasureName" xlink:to="lab_ecd_CoSelectedMeasureName" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ManagementBrandPromotionAndLoyaltyFeesMember_019dd0c6-b5cb-74ee-b421-1e2c6e52d687_terseLabel_en-US" xlink:label="lab_opi_ManagementBrandPromotionAndLoyaltyFeesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Management, Brand Promotion And Loyalty Fees</link:label>
    <link:label id="lab_opi_ManagementBrandPromotionAndLoyaltyFeesMember_label_en-US" xlink:label="lab_opi_ManagementBrandPromotionAndLoyaltyFeesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Management, Brand Promotion And Loyalty Fees [Member]</link:label>
    <link:label id="lab_opi_ManagementBrandPromotionAndLoyaltyFeesMember_documentation_en-US" xlink:label="lab_opi_ManagementBrandPromotionAndLoyaltyFeesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Management, Brand Promotion And Loyalty Fees</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ManagementBrandPromotionAndLoyaltyFeesMember" xlink:href="opi-20251231.xsd#opi_ManagementBrandPromotionAndLoyaltyFeesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ManagementBrandPromotionAndLoyaltyFeesMember" xlink:to="lab_opi_ManagementBrandPromotionAndLoyaltyFeesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A6315HillsideCenterColumbiaMDMember_019dbc7a-b286-7e02-8c1f-630535914025_terseLabel_en-US" xlink:label="lab_opi_A6315HillsideCenterColumbiaMDMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">6315 Hillside Center, Columbia, MD</link:label>
    <link:label id="lab_opi_A6315HillsideCenterColumbiaMDMember_label_en-US" xlink:label="lab_opi_A6315HillsideCenterColumbiaMDMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">6315 Hillside Center, Columbia, MD [Member]</link:label>
    <link:label id="lab_opi_A6315HillsideCenterColumbiaMDMember_documentation_en-US" xlink:label="lab_opi_A6315HillsideCenterColumbiaMDMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">6315 Hillside Center, Columbia, MD</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A6315HillsideCenterColumbiaMDMember" xlink:href="opi-20251231.xsd#opi_A6315HillsideCenterColumbiaMDMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A6315HillsideCenterColumbiaMDMember" xlink:to="lab_opi_A6315HillsideCenterColumbiaMDMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueDisclosureItemAmountsDomain_019dbc7a-b287-7436-af7a-0ba8f141b1b1_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueDisclosureItemAmountsDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair Value Measurement [Domain]</link:label>
    <link:label id="lab_us-gaap_FairValueDisclosureItemAmountsDomain_label_en-US" xlink:label="lab_us-gaap_FairValueDisclosureItemAmountsDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value Measurement [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain" xlink:to="lab_us-gaap_FairValueDisclosureItemAmountsDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtDisclosureTextBlock_019dbc7a-b287-7855-86b8-0574e877a263_terseLabel_en-US" xlink:label="lab_us-gaap_DebtDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Indebtedness</link:label>
    <link:label id="lab_us-gaap_DebtDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_DebtDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtDisclosureTextBlock" xlink:to="lab_us-gaap_DebtDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_TrdArrSecuritiesAggAvailAmt_terseLabel_en-US" xlink:label="lab_ecd_TrdArrSecuritiesAggAvailAmt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate Available</link:label>
    <link:label id="lab_ecd_TrdArrSecuritiesAggAvailAmt_label_en-US" xlink:label="lab_ecd_TrdArrSecuritiesAggAvailAmt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Trading Arrangement, Securities Aggregate Available Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_TrdArrSecuritiesAggAvailAmt" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_TrdArrSecuritiesAggAvailAmt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_TrdArrSecuritiesAggAvailAmt" xlink:to="lab_ecd_TrdArrSecuritiesAggAvailAmt" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFour_019dbc7a-b1cb-7c7a-87ed-4a3583f4b0ea_terseLabel_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2029</link:label>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFour_label_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Costs, Leasing Future Amortization Expense Year Four</link:label>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFour_documentation_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFour" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of amortization of deferred leasing costs expected to be recognized during year four of the five succeeding fiscal years.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFour" xlink:href="opi-20251231.xsd#opi_DeferredCostsLeasingFutureAmortizationExpenseYearFour"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFour" xlink:to="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFour" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockAppreciationRightsSARSMember_terseLabel_en-US" xlink:label="lab_us-gaap_StockAppreciationRightsSARSMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stock Appreciation Rights (SARs)</link:label>
    <link:label id="lab_us-gaap_StockAppreciationRightsSARSMember_label_en-US" xlink:label="lab_us-gaap_StockAppreciationRightsSARSMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Appreciation Rights (SARs) [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockAppreciationRightsSARSMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockAppreciationRightsSARSMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockAppreciationRightsSARSMember" xlink:to="lab_us-gaap_StockAppreciationRightsSARSMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_Redland540RockvilleMDMember_019dbc7a-b286-78a2-a93f-a5b4d6042010_terseLabel_en-US" xlink:label="lab_opi_Redland540RockvilleMDMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Redland 540, Rockville, MD</link:label>
    <link:label id="lab_opi_Redland540RockvilleMDMember_label_en-US" xlink:label="lab_opi_Redland540RockvilleMDMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Redland 540, Rockville, MD [Member]</link:label>
    <link:label id="lab_opi_Redland540RockvilleMDMember_documentation_en-US" xlink:label="lab_opi_Redland540RockvilleMDMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Redland 540, Rockville, MD [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_Redland540RockvilleMDMember" xlink:href="opi-20251231.xsd#opi_Redland540RockvilleMDMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_Redland540RockvilleMDMember" xlink:to="lab_opi_Redland540RockvilleMDMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationAwardTrancheTwoMember_019dbc7a-b1cb-7f6d-927b-2d7e1e0bcf0c_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationAwardTrancheTwoMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement, Tranche 2</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationAwardTrancheTwoMember_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationAwardTrancheTwoMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement, Tranche Two [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationAwardTrancheTwoMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationAwardTrancheTwoMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationAwardTrancheTwoMember" xlink:to="lab_us-gaap_ShareBasedCompensationAwardTrancheTwoMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019dbc7a-b1cb-7e83-8b59-68934de5097b_verboseLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Weighted average common shares outstanding (diluted) (in shares)</link:label>
    <link:label id="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019dbc7a-b1cb-7556-b5d7-f157b4e1c0d4_terseLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted average common shares outstanding - diluted (in shares)</link:label>
    <link:label id="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_label_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Weighted Average Number of Shares Outstanding, Diluted</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:to="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LongTermDebtReorganizedCommonStockPercentageOfClaimsReceivable_019dff20-ac4b-70a2-adde-857280ecd9a5_terseLabel_en-US" xlink:label="lab_opi_LongTermDebtReorganizedCommonStockPercentageOfClaimsReceivable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage of claims receivable</link:label>
    <link:label id="lab_opi_LongTermDebtReorganizedCommonStockPercentageOfClaimsReceivable_label_en-US" xlink:label="lab_opi_LongTermDebtReorganizedCommonStockPercentageOfClaimsReceivable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Reorganized Common Stock, Percentage Of Claims Receivable</link:label>
    <link:label id="lab_opi_LongTermDebtReorganizedCommonStockPercentageOfClaimsReceivable_documentation_en-US" xlink:label="lab_opi_LongTermDebtReorganizedCommonStockPercentageOfClaimsReceivable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Reorganized Common Stock, Percentage Of Claims Receivable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LongTermDebtReorganizedCommonStockPercentageOfClaimsReceivable" xlink:href="opi-20251231.xsd#opi_LongTermDebtReorganizedCommonStockPercentageOfClaimsReceivable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LongTermDebtReorganizedCommonStockPercentageOfClaimsReceivable" xlink:to="lab_opi_LongTermDebtReorganizedCommonStockPercentageOfClaimsReceivable" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_NonGaapMeasureDescriptionTextBlock_terseLabel_en-US" xlink:label="lab_ecd_NonGaapMeasureDescriptionTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Non-GAAP Measure Description</link:label>
    <link:label id="lab_ecd_NonGaapMeasureDescriptionTextBlock_label_en-US" xlink:label="lab_ecd_NonGaapMeasureDescriptionTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Non-GAAP Measure Description [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_NonGaapMeasureDescriptionTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_NonGaapMeasureDescriptionTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_NonGaapMeasureDescriptionTextBlock" xlink:to="lab_ecd_NonGaapMeasureDescriptionTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReorganizationUnderChapter11OfUSBankruptcyCodeDisclosureTextBlock_019dd071-fd93-7257-a52d-c199bec109c7_terseLabel_en-US" xlink:label="lab_us-gaap_ReorganizationUnderChapter11OfUSBankruptcyCodeDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Condensed Combined Debtor-in-Possession Financial Information</link:label>
    <link:label id="lab_us-gaap_ReorganizationUnderChapter11OfUSBankruptcyCodeDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_ReorganizationUnderChapter11OfUSBankruptcyCodeDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reorganization under Chapter 11 of US Bankruptcy Code Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReorganizationUnderChapter11OfUSBankruptcyCodeDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReorganizationUnderChapter11OfUSBankruptcyCodeDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReorganizationUnderChapter11OfUSBankruptcyCodeDisclosureTextBlock" xlink:to="lab_us-gaap_ReorganizationUnderChapter11OfUSBankruptcyCodeDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearOne_019dbc7a-b287-7b1c-a16a-8e1b0d144eac_terseLabel_en-US" xlink:label="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearOne" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2026 (in shares)</link:label>
    <link:label id="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearOne_label_en-US" xlink:label="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearOne" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share Based Compensation Arrangement By Share Based Payment Award, Nonvested Shares Scheduled To Vest In Year One</link:label>
    <link:label id="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearOne_documentation_en-US" xlink:label="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearOne" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of non-vested shares that are scheduled to vest in year one.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearOne" xlink:href="opi-20251231.xsd#opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearOne"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearOne" xlink:to="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearOne" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntitySmallBusiness_019dbc7a-b1cb-705c-aaa3-acf68b7531d4_terseLabel_en-US" xlink:label="lab_dei_EntitySmallBusiness" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Small Business</link:label>
    <link:label id="lab_dei_EntitySmallBusiness_label_en-US" xlink:label="lab_dei_EntitySmallBusiness" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Small Business</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntitySmallBusiness"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntitySmallBusiness" xlink:to="lab_dei_EntitySmallBusiness" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherCostAndExpenseOperating_019dbc7a-b286-7685-8f5d-1f5baf3309d0_terseLabel_en-US" xlink:label="lab_us-gaap_OtherCostAndExpenseOperating" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other operating expenses</link:label>
    <link:label id="lab_us-gaap_OtherCostAndExpenseOperating_label_en-US" xlink:label="lab_us-gaap_OtherCostAndExpenseOperating" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Cost and Expense, Operating</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCostAndExpenseOperating" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherCostAndExpenseOperating"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherCostAndExpenseOperating" xlink:to="lab_us-gaap_OtherCostAndExpenseOperating" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentTransitionReport_019dbc7a-b1cb-7f26-b7eb-6def44d92f6c_terseLabel_en-US" xlink:label="lab_dei_DocumentTransitionReport" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Document Transition Report</link:label>
    <link:label id="lab_dei_DocumentTransitionReport_label_en-US" xlink:label="lab_dei_DocumentTransitionReport" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Document Transition Report</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentTransitionReport"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentTransitionReport" xlink:to="lab_dei_DocumentTransitionReport" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_NonCashReorganizationItems_019dd0f5-39f6-719b-9a77-0602ac1fb4ca_verboseLabel_en-US" xlink:label="lab_opi_NonCashReorganizationItems" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Non-cash reorganization items</link:label>
    <link:label id="lab_opi_NonCashReorganizationItems_label_en-US" xlink:label="lab_opi_NonCashReorganizationItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Non-Cash Reorganization Items</link:label>
    <link:label id="lab_opi_NonCashReorganizationItems_documentation_en-US" xlink:label="lab_opi_NonCashReorganizationItems" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Non-Cash Reorganization Items</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_NonCashReorganizationItems" xlink:href="opi-20251231.xsd#opi_NonCashReorganizationItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_NonCashReorganizationItems" xlink:to="lab_opi_NonCashReorganizationItems" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AwardUndrlygSecuritiesAmt_terseLabel_en-US" xlink:label="lab_ecd_AwardUndrlygSecuritiesAmt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Underlying Securities</link:label>
    <link:label id="lab_ecd_AwardUndrlygSecuritiesAmt_label_en-US" xlink:label="lab_ecd_AwardUndrlygSecuritiesAmt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Award Underlying Securities Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AwardUndrlygSecuritiesAmt" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AwardUndrlygSecuritiesAmt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AwardUndrlygSecuritiesAmt" xlink:to="lab_ecd_AwardUndrlygSecuritiesAmt" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityComponentDomain_019dbc7a-b287-7413-9d6d-64d5d28616c9_terseLabel_en-US" xlink:label="lab_us-gaap_EquityComponentDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity Component [Domain]</link:label>
    <link:label id="lab_us-gaap_EquityComponentDomain_label_en-US" xlink:label="lab_us-gaap_EquityComponentDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Component [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityComponentDomain" xlink:to="lab_us-gaap_EquityComponentDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentPeriodEndDate_019dbc7a-b287-75e2-99a8-704300c3209c_terseLabel_en-US" xlink:label="lab_dei_DocumentPeriodEndDate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Document Period End Date</link:label>
    <link:label id="lab_dei_DocumentPeriodEndDate_label_en-US" xlink:label="lab_dei_DocumentPeriodEndDate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Document Period End Date</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentPeriodEndDate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentPeriodEndDate" xlink:to="lab_dei_DocumentPeriodEndDate" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A77RioRoblesDriveSanJoseCAMember_019dbc7a-b1cb-7ed8-87ac-ab3cc85fdd74_terseLabel_en-US" xlink:label="lab_opi_A77RioRoblesDriveSanJoseCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">77 Rio Robles Drive, San Jose, CA</link:label>
    <link:label id="lab_opi_A77RioRoblesDriveSanJoseCAMember_label_en-US" xlink:label="lab_opi_A77RioRoblesDriveSanJoseCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">77 Rio Robles Drive, San Jose, CA [Member]</link:label>
    <link:label id="lab_opi_A77RioRoblesDriveSanJoseCAMember_documentation_en-US" xlink:label="lab_opi_A77RioRoblesDriveSanJoseCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">77 Rio Robles Drive, San Jose, CA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A77RioRoblesDriveSanJoseCAMember" xlink:href="opi-20251231.xsd#opi_A77RioRoblesDriveSanJoseCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A77RioRoblesDriveSanJoseCAMember" xlink:to="lab_opi_A77RioRoblesDriveSanJoseCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AwardsCloseToMnpiDiscTableTextBlock_terseLabel_en-US" xlink:label="lab_ecd_AwardsCloseToMnpiDiscTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Awards Close in Time to MNPI Disclosures, Table</link:label>
    <link:label id="lab_ecd_AwardsCloseToMnpiDiscTableTextBlock_label_en-US" xlink:label="lab_ecd_AwardsCloseToMnpiDiscTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Awards Close in Time to MNPI Disclosures [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AwardsCloseToMnpiDiscTableTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AwardsCloseToMnpiDiscTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AwardsCloseToMnpiDiscTableTextBlock" xlink:to="lab_ecd_AwardsCloseToMnpiDiscTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_NumberOfStatesInWhichRealEstatePropertiesHeld_019dbc7a-b287-7f99-ac47-cd3594ed5f2f_terseLabel_en-US" xlink:label="lab_opi_NumberOfStatesInWhichRealEstatePropertiesHeld" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of states in which acquired properties located</link:label>
    <link:label id="lab_opi_NumberOfStatesInWhichRealEstatePropertiesHeld_label_en-US" xlink:label="lab_opi_NumberOfStatesInWhichRealEstatePropertiesHeld" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number Of States In Which Real Estate Properties Held</link:label>
    <link:label id="lab_opi_NumberOfStatesInWhichRealEstatePropertiesHeld_documentation_en-US" xlink:label="lab_opi_NumberOfStatesInWhichRealEstatePropertiesHeld" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The number of states in which real estate owned by the entity is located as of the balance sheet date.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_NumberOfStatesInWhichRealEstatePropertiesHeld" xlink:href="opi-20251231.xsd#opi_NumberOfStatesInWhichRealEstatePropertiesHeld"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_NumberOfStatesInWhichRealEstatePropertiesHeld" xlink:to="lab_opi_NumberOfStatesInWhichRealEstatePropertiesHeld" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A1800NovellPlaceProvoUTMember_019dbc7a-b287-7c16-a642-c9dd23b26f01_terseLabel_en-US" xlink:label="lab_opi_A1800NovellPlaceProvoUTMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">1800 Novell Place, Provo, UT</link:label>
    <link:label id="lab_opi_A1800NovellPlaceProvoUTMember_label_en-US" xlink:label="lab_opi_A1800NovellPlaceProvoUTMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">1800 Novell Place, Provo, UT [Member]</link:label>
    <link:label id="lab_opi_A1800NovellPlaceProvoUTMember_documentation_en-US" xlink:label="lab_opi_A1800NovellPlaceProvoUTMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">1800 Novell Place, Provo, UT [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A1800NovellPlaceProvoUTMember" xlink:href="opi-20251231.xsd#opi_A1800NovellPlaceProvoUTMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A1800NovellPlaceProvoUTMember" xlink:to="lab_opi_A1800NovellPlaceProvoUTMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RisksAndUncertaintiesAbstract_019dbc7a-b286-7501-90fc-a6202657a172_terseLabel_en-US" xlink:label="lab_us-gaap_RisksAndUncertaintiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Risks and Uncertainties [Abstract]</link:label>
    <link:label id="lab_us-gaap_RisksAndUncertaintiesAbstract_label_en-US" xlink:label="lab_us-gaap_RisksAndUncertaintiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Risks and Uncertainties [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RisksAndUncertaintiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RisksAndUncertaintiesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RisksAndUncertaintiesAbstract" xlink:to="lab_us-gaap_RisksAndUncertaintiesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LakewoodCOMember_019dbc7a-b287-70f4-add5-2f1777c53828_terseLabel_en-US" xlink:label="lab_opi_LakewoodCOMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lakewood, CO</link:label>
    <link:label id="lab_opi_LakewoodCOMember_label_en-US" xlink:label="lab_opi_LakewoodCOMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lakewood, CO [Member]</link:label>
    <link:label id="lab_opi_LakewoodCOMember_documentation_en-US" xlink:label="lab_opi_LakewoodCOMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lakewood, CO</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LakewoodCOMember" xlink:href="opi-20251231.xsd#opi_LakewoodCOMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LakewoodCOMember" xlink:to="lab_opi_LakewoodCOMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_InterestExpenseDebtPortionNotAccrued_019dd0be-065c-73ff-b65e-3ec6e1ebdffa_terseLabel_en-US" xlink:label="lab_opi_InterestExpenseDebtPortionNotAccrued" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate contractual interest expense not recognized</link:label>
    <link:label id="lab_opi_InterestExpenseDebtPortionNotAccrued_label_en-US" xlink:label="lab_opi_InterestExpenseDebtPortionNotAccrued" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Expense, Debt, Portion Not Accrued</link:label>
    <link:label id="lab_opi_InterestExpenseDebtPortionNotAccrued_documentation_en-US" xlink:label="lab_opi_InterestExpenseDebtPortionNotAccrued" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Interest Expense, Debt, Portion Not Accrued</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_InterestExpenseDebtPortionNotAccrued" xlink:href="opi-20251231.xsd#opi_InterestExpenseDebtPortionNotAccrued"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_InterestExpenseDebtPortionNotAccrued" xlink:to="lab_opi_InterestExpenseDebtPortionNotAccrued" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentType_019dbc7a-b286-713e-ba84-1fad9b5bd113_terseLabel_en-US" xlink:label="lab_dei_DocumentType" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Document Type</link:label>
    <link:label id="lab_dei_DocumentType_label_en-US" xlink:label="lab_dei_DocumentType" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Document Type</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentType"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentType" xlink:to="lab_dei_DocumentType" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EarningsPerShareTextBlock_019dbc7a-b286-75e4-9582-d48bcc697e13_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Per Common Share Amounts</link:label>
    <link:label id="lab_us-gaap_EarningsPerShareTextBlock_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Earnings Per Share [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareTextBlock" xlink:to="lab_us-gaap_EarningsPerShareTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_OutstandingRecoveryIndName_terseLabel_en-US" xlink:label="lab_ecd_OutstandingRecoveryIndName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Name</link:label>
    <link:label id="lab_ecd_OutstandingRecoveryIndName_label_en-US" xlink:label="lab_ecd_OutstandingRecoveryIndName" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Outstanding Recovery, Individual Name</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_OutstandingRecoveryIndName" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_OutstandingRecoveryIndName"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_OutstandingRecoveryIndName" xlink:to="lab_ecd_OutstandingRecoveryIndName" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RangeAxis_019dbc7a-b286-7972-a150-1927ed787403_terseLabel_en-US" xlink:label="lab_srt_RangeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statistical Measurement [Axis]</link:label>
    <link:label id="lab_srt_RangeAxis_label_en-US" xlink:label="lab_srt_RangeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statistical Measurement [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RangeAxis" xlink:to="lab_srt_RangeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ProceedsFromIssuanceOfDebtorInPossessionSecuredTermLoan_019dbc8c-161f-767a-81b6-0749ca3b84ef_terseLabel_en-US" xlink:label="lab_opi_ProceedsFromIssuanceOfDebtorInPossessionSecuredTermLoan" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Borrowings on debtor-in-possession secured term loan</link:label>
    <link:label id="lab_opi_ProceedsFromIssuanceOfDebtorInPossessionSecuredTermLoan_label_en-US" xlink:label="lab_opi_ProceedsFromIssuanceOfDebtorInPossessionSecuredTermLoan" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds From Issuance Of Debtor-In-Possession Secured Term Loan</link:label>
    <link:label id="lab_opi_ProceedsFromIssuanceOfDebtorInPossessionSecuredTermLoan_documentation_en-US" xlink:label="lab_opi_ProceedsFromIssuanceOfDebtorInPossessionSecuredTermLoan" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Proceeds From Issuance Of Debtor-In-Possession Secured Term Loan</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ProceedsFromIssuanceOfDebtorInPossessionSecuredTermLoan" xlink:href="opi-20251231.xsd#opi_ProceedsFromIssuanceOfDebtorInPossessionSecuredTermLoan"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ProceedsFromIssuanceOfDebtorInPossessionSecuredTermLoan" xlink:to="lab_opi_ProceedsFromIssuanceOfDebtorInPossessionSecuredTermLoan" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AggtErrCompAmt_terseLabel_en-US" xlink:label="lab_ecd_AggtErrCompAmt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate Erroneous Compensation Amount</link:label>
    <link:label id="lab_ecd_AggtErrCompAmt_label_en-US" xlink:label="lab_ecd_AggtErrCompAmt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Aggregate Erroneous Compensation Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AggtErrCompAmt" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AggtErrCompAmt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AggtErrCompAmt" xlink:to="lab_ecd_AggtErrCompAmt" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_PeerGroupIssuersFnTextBlock_terseLabel_en-US" xlink:label="lab_ecd_PeerGroupIssuersFnTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Peer Group Issuers, Footnote</link:label>
    <link:label id="lab_ecd_PeerGroupIssuersFnTextBlock_label_en-US" xlink:label="lab_ecd_PeerGroupIssuersFnTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Peer Group Issuers, Footnote [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_PeerGroupIssuersFnTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_PeerGroupIssuersFnTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_PeerGroupIssuersFnTextBlock" xlink:to="lab_ecd_PeerGroupIssuersFnTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_PropertyManagementAgreementConstructionSupervisionFeesMember_019dbc7a-b1cb-7da2-9fc3-637d8c48d25e_terseLabel_en-US" xlink:label="lab_opi_PropertyManagementAgreementConstructionSupervisionFeesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Construction supervision fees</link:label>
    <link:label id="lab_opi_PropertyManagementAgreementConstructionSupervisionFeesMember_label_en-US" xlink:label="lab_opi_PropertyManagementAgreementConstructionSupervisionFeesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property Management Agreement, Construction Supervision Fees [Member]</link:label>
    <link:label id="lab_opi_PropertyManagementAgreementConstructionSupervisionFeesMember_documentation_en-US" xlink:label="lab_opi_PropertyManagementAgreementConstructionSupervisionFeesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Property Management Agreement, Construction Supervision Fees</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_PropertyManagementAgreementConstructionSupervisionFeesMember" xlink:href="opi-20251231.xsd#opi_PropertyManagementAgreementConstructionSupervisionFeesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_PropertyManagementAgreementConstructionSupervisionFeesMember" xlink:to="lab_opi_PropertyManagementAgreementConstructionSupervisionFeesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019dbc7a-b1cb-7b2e-8b0f-1248a5037bd7_totalLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net loss used in calculating earnings per common share</link:label>
    <link:label id="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_label_en-US" xlink:label="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Income (Loss) Available to Common Stockholders, Basic</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:to="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BelowMarketLeaseGross_019dbc7a-b1cb-7d1b-8cb0-7111659434f7_terseLabel_en-US" xlink:label="lab_us-gaap_BelowMarketLeaseGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Capitalized below market lease values</link:label>
    <link:label id="lab_us-gaap_BelowMarketLeaseGross_label_en-US" xlink:label="lab_us-gaap_BelowMarketLeaseGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Below Market Lease, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseGross" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BelowMarketLeaseGross"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BelowMarketLeaseGross" xlink:to="lab_us-gaap_BelowMarketLeaseGross" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAndAccumulatedDepreciationRealEstateImpairmentOrWriteDownsNet_019dbc7a-b286-7c41-9080-48dd4fd4e0ba_negatedLabel_en-US" xlink:label="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAndAccumulatedDepreciationRealEstateImpairmentOrWriteDownsNet" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Impairment/ Writedowns</link:label>
    <link:label id="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAndAccumulatedDepreciationRealEstateImpairmentOrWriteDownsNet_label_en-US" xlink:label="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAndAccumulatedDepreciationRealEstateImpairmentOrWriteDownsNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment In Real Estate And Accumulated Depreciation, Real Estate Impairment Or Write-Downs, Net</link:label>
    <link:label id="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAndAccumulatedDepreciationRealEstateImpairmentOrWriteDownsNet_documentation_en-US" xlink:label="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAndAccumulatedDepreciationRealEstateImpairmentOrWriteDownsNet" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of impairment or writedowns for the property as of the balance sheet date.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAndAccumulatedDepreciationRealEstateImpairmentOrWriteDownsNet" xlink:href="opi-20251231.xsd#opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAndAccumulatedDepreciationRealEstateImpairmentOrWriteDownsNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAndAccumulatedDepreciationRealEstateImpairmentOrWriteDownsNet" xlink:to="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAndAccumulatedDepreciationRealEstateImpairmentOrWriteDownsNet" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LineOfCredit_019dd064-e327-7750-bc14-bc69babe59f2_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCredit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Borrowings outstanding</link:label>
    <link:label id="lab_us-gaap_LineOfCredit_label_en-US" xlink:label="lab_us-gaap_LineOfCredit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Line of Credit</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCredit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCredit" xlink:to="lab_us-gaap_LineOfCredit" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SharesOutstanding_019dbc7a-b286-752e-bd9d-5d05bfdce1b5_periodStartLabel_en-US" xlink:label="lab_us-gaap_SharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Balance beginning (in shares)</link:label>
    <link:label id="lab_us-gaap_SharesOutstanding_019dbc7a-b286-796a-ac29-63b772b8ff70_periodEndLabel_en-US" xlink:label="lab_us-gaap_SharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Balance ending (in shares)</link:label>
    <link:label id="lab_us-gaap_SharesOutstanding_label_en-US" xlink:label="lab_us-gaap_SharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Shares, Outstanding</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharesOutstanding"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SharesOutstanding" xlink:to="lab_us-gaap_SharesOutstanding" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019dbc7a-b1cb-74b0-915c-ba89e1a43814_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Related Party Transaction [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="lab_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EarningsPerShareDiluted_019dbc7a-b286-78df-abab-1f8ee529e7b2_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareDiluted" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net loss (diluted) (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_EarningsPerShareDiluted_019dbc7a-b286-7762-a6b2-26e62f1ad311_verboseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareDiluted" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Net loss per common share - diluted (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_EarningsPerShareDiluted_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareDiluted" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Earnings Per Share, Diluted</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareDiluted" xlink:to="lab_us-gaap_EarningsPerShareDiluted" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears_019dbc7a-b286-73b6-b577-f7ef5520e54f_terseLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2030</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received, Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears" xlink:to="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionRequiredEscrowDepositPercentOfGrossRevenues_019dbc7a-b1cb-75ff-ab14-3d30545a51a6_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionRequiredEscrowDepositPercentOfGrossRevenues" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Required escrow deposit, percent of gross revenues</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionRequiredEscrowDepositPercentOfGrossRevenues_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionRequiredEscrowDepositPercentOfGrossRevenues" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Required Escrow Deposit, Percent Of Gross Revenues</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionRequiredEscrowDepositPercentOfGrossRevenues_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionRequiredEscrowDepositPercentOfGrossRevenues" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Required Escrow Deposit, Percent Of Gross Revenues</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionRequiredEscrowDepositPercentOfGrossRevenues" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionRequiredEscrowDepositPercentOfGrossRevenues"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionRequiredEscrowDepositPercentOfGrossRevenues" xlink:to="lab_opi_RelatedPartyTransactionRequiredEscrowDepositPercentOfGrossRevenues" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A3600WisemanBoulevardSanAntonioTXMember_019dbc7a-b286-738e-a279-5ae9940731ed_terseLabel_en-US" xlink:label="lab_opi_A3600WisemanBoulevardSanAntonioTXMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">3600 Weismann Boulevard, San Antonio, TX</link:label>
    <link:label id="lab_opi_A3600WisemanBoulevardSanAntonioTXMember_label_en-US" xlink:label="lab_opi_A3600WisemanBoulevardSanAntonioTXMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">3600 Wiseman Boulevard, San Antonio, TX [Member]</link:label>
    <link:label id="lab_opi_A3600WisemanBoulevardSanAntonioTXMember_documentation_en-US" xlink:label="lab_opi_A3600WisemanBoulevardSanAntonioTXMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">3600 Wiseman Boulevard, San Antonio, TX</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A3600WisemanBoulevardSanAntonioTXMember" xlink:href="opi-20251231.xsd#opi_A3600WisemanBoulevardSanAntonioTXMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A3600WisemanBoulevardSanAntonioTXMember" xlink:to="lab_opi_A3600WisemanBoulevardSanAntonioTXMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SecuredTermLoanDue2027Member_019dd0fc-d9e1-7ee8-b888-910e0f57b809_terseLabel_en-US" xlink:label="lab_opi_SecuredTermLoanDue2027Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Secured term loan, due in 2027</link:label>
    <link:label id="lab_opi_SecuredTermLoanDue2027Member_label_en-US" xlink:label="lab_opi_SecuredTermLoanDue2027Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Secured Term Loan Due 2027 [Member]</link:label>
    <link:label id="lab_opi_SecuredTermLoanDue2027Member_documentation_en-US" xlink:label="lab_opi_SecuredTermLoanDue2027Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Secured Term Loan Due 2027</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SecuredTermLoanDue2027Member" xlink:href="opi-20251231.xsd#opi_SecuredTermLoanDue2027Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SecuredTermLoanDue2027Member" xlink:to="lab_opi_SecuredTermLoanDue2027Member" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A9960MaylandDriveRichmondVAMember_019dbc7a-b286-764f-9410-1f09f5796763_terseLabel_en-US" xlink:label="lab_opi_A9960MaylandDriveRichmondVAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">9960 Mayland Drive, Richmond, VA</link:label>
    <link:label id="lab_opi_A9960MaylandDriveRichmondVAMember_label_en-US" xlink:label="lab_opi_A9960MaylandDriveRichmondVAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">9960 Mayland Drive, Richmond, VA [Member]</link:label>
    <link:label id="lab_opi_A9960MaylandDriveRichmondVAMember_documentation_en-US" xlink:label="lab_opi_A9960MaylandDriveRichmondVAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">9960 Mayland Drive [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A9960MaylandDriveRichmondVAMember" xlink:href="opi-20251231.xsd#opi_A9960MaylandDriveRichmondVAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A9960MaylandDriveRichmondVAMember" xlink:to="lab_opi_A9960MaylandDriveRichmondVAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_019dbc7a-b1cb-7688-82f2-34e5817d9996_terseLabel_en-US" xlink:label="lab_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of shares sold (in shares)</link:label>
    <link:label id="lab_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_label_en-US" xlink:label="lab_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale of Stock, Number of Shares Issued in Transaction</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction" xlink:to="lab_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ContractualInterestPolicyPolicyTextBlock_019dd0b4-6605-72a2-b7ba-8e3d08166302_terseLabel_en-US" xlink:label="lab_opi_ContractualInterestPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Contractual interest</link:label>
    <link:label id="lab_opi_ContractualInterestPolicyPolicyTextBlock_label_en-US" xlink:label="lab_opi_ContractualInterestPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Contractual Interest, Policy [Policy Text Block]</link:label>
    <link:label id="lab_opi_ContractualInterestPolicyPolicyTextBlock_documentation_en-US" xlink:label="lab_opi_ContractualInterestPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Contractual Interest, Policy</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ContractualInterestPolicyPolicyTextBlock" xlink:href="opi-20251231.xsd#opi_ContractualInterestPolicyPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ContractualInterestPolicyPolicyTextBlock" xlink:to="lab_opi_ContractualInterestPolicyPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationLineItems_019dbc7a-b286-7483-87bc-cf0dc9ee8aa2_terseLabel_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real estate and accumulated depreciation</link:label>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationLineItems_label_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationLineItems" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RealEstateAndAccumulatedDepreciationLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems" xlink:to="lab_srt_RealEstateAndAccumulatedDepreciationLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEleven_019dbc7a-b287-7493-8b4e-e18861b48c6c_terseLabel_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEleven" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2036</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEleven_label_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEleven" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right Exercisable In Year Eleven</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEleven_documentation_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEleven" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right Exercisable In Year Eleven</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEleven" xlink:href="opi-20251231.xsd#opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEleven"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEleven" xlink:to="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEleven" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_AuditorLocation_019dbc7a-b286-7fc0-9213-2ec52a908771_terseLabel_en-US" xlink:label="lab_dei_AuditorLocation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Auditor Location</link:label>
    <link:label id="lab_dei_AuditorLocation_label_en-US" xlink:label="lab_dei_AuditorLocation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Auditor Location</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AuditorLocation" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_AuditorLocation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_AuditorLocation" xlink:to="lab_dei_AuditorLocation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_019dbc7a-b287-77f3-b18a-5e61ad4f68e1_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Common share repurchases</link:label>
    <link:label id="lab_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_label_en-US" xlink:label="lab_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Repurchased and Retired During Period, Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" xlink:to="lab_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ProsperityMetroPlazaMember_019dbc7a-b1cb-7b5e-becf-d34b601cafc9_terseLabel_en-US" xlink:label="lab_opi_ProsperityMetroPlazaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Prosperity Metro Plaza</link:label>
    <link:label id="lab_opi_ProsperityMetroPlazaMember_label_en-US" xlink:label="lab_opi_ProsperityMetroPlazaMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Prosperity Metro Plaza [Member]</link:label>
    <link:label id="lab_opi_ProsperityMetroPlazaMember_documentation_en-US" xlink:label="lab_opi_ProsperityMetroPlazaMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Prosperity Metro Plaza [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ProsperityMetroPlazaMember" xlink:href="opi-20251231.xsd#opi_ProsperityMetroPlazaMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ProsperityMetroPlazaMember" xlink:to="lab_opi_ProsperityMetroPlazaMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A7601And7635InteractiveWayIndianapolisINMember_019dbc7a-b286-72d1-98df-f06e240dec13_terseLabel_en-US" xlink:label="lab_opi_A7601And7635InteractiveWayIndianapolisINMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">7601 and 7635 Interactive Way, Indianapolis, IN</link:label>
    <link:label id="lab_opi_A7601And7635InteractiveWayIndianapolisINMember_label_en-US" xlink:label="lab_opi_A7601And7635InteractiveWayIndianapolisINMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">7601 and 7635 Interactive Way, Indianapolis, IN [Member]</link:label>
    <link:label id="lab_opi_A7601And7635InteractiveWayIndianapolisINMember_documentation_en-US" xlink:label="lab_opi_A7601And7635InteractiveWayIndianapolisINMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">7601 and 7635 Interactive Way, Indianapolis, IN</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A7601And7635InteractiveWayIndianapolisINMember" xlink:href="opi-20251231.xsd#opi_A7601And7635InteractiveWayIndianapolisINMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A7601And7635InteractiveWayIndianapolisINMember" xlink:to="lab_opi_A7601And7635InteractiveWayIndianapolisINMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A65BowdoinStreetS.BurlingtonVTMember_019dbc7a-b287-742b-a881-137c73f86ffb_terseLabel_en-US" xlink:label="lab_opi_A65BowdoinStreetS.BurlingtonVTMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">65 Bowdoin Street, S. Burlington, VT</link:label>
    <link:label id="lab_opi_A65BowdoinStreetS.BurlingtonVTMember_label_en-US" xlink:label="lab_opi_A65BowdoinStreetS.BurlingtonVTMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">65 Bowdoin Street, S. Burlington, VT [Member]</link:label>
    <link:label id="lab_opi_A65BowdoinStreetS.BurlingtonVTMember_documentation_en-US" xlink:label="lab_opi_A65BowdoinStreetS.BurlingtonVTMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">65 Bowdoin Street, S. Burlington, VT</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A65BowdoinStreetS.BurlingtonVTMember" xlink:href="opi-20251231.xsd#opi_A65BowdoinStreetS.BurlingtonVTMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A65BowdoinStreetS.BurlingtonVTMember" xlink:to="lab_opi_A65BowdoinStreetS.BurlingtonVTMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LiabilitiesSubjectToCompromiseAccruedInterest_019dd0ba-73b7-7957-a484-a6fbc5a3b25c_terseLabel_en-US" xlink:label="lab_opi_LiabilitiesSubjectToCompromiseAccruedInterest" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accrued interest</link:label>
    <link:label id="lab_opi_LiabilitiesSubjectToCompromiseAccruedInterest_label_en-US" xlink:label="lab_opi_LiabilitiesSubjectToCompromiseAccruedInterest" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities Subject To Compromise, Accrued Interest</link:label>
    <link:label id="lab_opi_LiabilitiesSubjectToCompromiseAccruedInterest_documentation_en-US" xlink:label="lab_opi_LiabilitiesSubjectToCompromiseAccruedInterest" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Liabilities Subject To Compromise, Accrued Interest</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LiabilitiesSubjectToCompromiseAccruedInterest" xlink:href="opi-20251231.xsd#opi_LiabilitiesSubjectToCompromiseAccruedInterest"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LiabilitiesSubjectToCompromiseAccruedInterest" xlink:to="lab_opi_LiabilitiesSubjectToCompromiseAccruedInterest" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ScheduleOfJointVenturesTableTextBlock_019dbc7a-b1cb-7fd2-9421-e9716209346d_terseLabel_en-US" xlink:label="lab_opi_ScheduleOfJointVenturesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Joint Ventures</link:label>
    <link:label id="lab_opi_ScheduleOfJointVenturesTableTextBlock_label_en-US" xlink:label="lab_opi_ScheduleOfJointVenturesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule Of Joint Ventures [Table Text Block]</link:label>
    <link:label id="lab_opi_ScheduleOfJointVenturesTableTextBlock_documentation_en-US" xlink:label="lab_opi_ScheduleOfJointVenturesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Schedule Of Joint Ventures [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ScheduleOfJointVenturesTableTextBlock" xlink:href="opi-20251231.xsd#opi_ScheduleOfJointVenturesTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ScheduleOfJointVenturesTableTextBlock" xlink:to="lab_opi_ScheduleOfJointVenturesTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ManagementAgreementRealizedReturnMember_019dd0eb-b81c-76af-b28e-00abb3e428b7_terseLabel_en-US" xlink:label="lab_opi_ManagementAgreementRealizedReturnMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Management Agreement Realized Return</link:label>
    <link:label id="lab_opi_ManagementAgreementRealizedReturnMember_label_en-US" xlink:label="lab_opi_ManagementAgreementRealizedReturnMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Management Agreement Realized Return [Member]</link:label>
    <link:label id="lab_opi_ManagementAgreementRealizedReturnMember_documentation_en-US" xlink:label="lab_opi_ManagementAgreementRealizedReturnMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Management Agreement Realized Return</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ManagementAgreementRealizedReturnMember" xlink:href="opi-20251231.xsd#opi_ManagementAgreementRealizedReturnMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ManagementAgreementRealizedReturnMember" xlink:to="lab_opi_ManagementAgreementRealizedReturnMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A2400SeniorUnsecuredNotesMember_019dbcab-1aff-7fe7-96ef-9a2459c63621_terseLabel_en-US" xlink:label="lab_opi_A2400SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior unsecured notes, 2.400% interest rate, due in 2027</link:label>
    <link:label id="lab_opi_A2400SeniorUnsecuredNotesMember_019dbc7a-b287-7348-a824-ac4276861428_verboseLabel_en-US" xlink:label="lab_opi_A2400SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Existing 3.450% 2031 Notes</link:label>
    <link:label id="lab_opi_A2400SeniorUnsecuredNotesMember_label_en-US" xlink:label="lab_opi_A2400SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2.400% Senior Unsecured Notes [Member]</link:label>
    <link:label id="lab_opi_A2400SeniorUnsecuredNotesMember_documentation_en-US" xlink:label="lab_opi_A2400SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2.400% Senior Unsecured Notes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A2400SeniorUnsecuredNotesMember" xlink:href="opi-20251231.xsd#opi_A2400SeniorUnsecuredNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A2400SeniorUnsecuredNotesMember" xlink:to="lab_opi_A2400SeniorUnsecuredNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A330BillericaRoadChelmsfordMAMember_019dbc7a-b1cb-71b3-a975-5891eaf5da66_terseLabel_en-US" xlink:label="lab_opi_A330BillericaRoadChelmsfordMAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">330 Billerica road, Chelmsford, MA</link:label>
    <link:label id="lab_opi_A330BillericaRoadChelmsfordMAMember_label_en-US" xlink:label="lab_opi_A330BillericaRoadChelmsfordMAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">330 Billerica road, Chelmsford, MA [Member]</link:label>
    <link:label id="lab_opi_A330BillericaRoadChelmsfordMAMember_documentation_en-US" xlink:label="lab_opi_A330BillericaRoadChelmsfordMAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">330 Billerica road, Chelmsford, MA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A330BillericaRoadChelmsfordMAMember" xlink:href="opi-20251231.xsd#opi_A330BillericaRoadChelmsfordMAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A330BillericaRoadChelmsfordMAMember" xlink:to="lab_opi_A330BillericaRoadChelmsfordMAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_019dbc7a-b286-7f80-8d04-f18dafecdd53_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2026</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Asset, Expected Amortization, Year Two</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentCarryingAmount_019dbc7a-b287-773d-9087-9351d2d5681e_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Borrowings outstanding</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentCarryingAmount_019dd065-f724-7073-90bb-4a33a6e26934_verboseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Outstanding principal amount</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentCarryingAmount_019dbc7a-b287-736e-94c5-cfdf6f73b506_totalLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentCarryingAmount_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentCarryingAmount" xlink:to="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityWellKnownSeasonedIssuer_019dbc7a-b1cb-7a7a-aa70-9038c5d5cc5b_terseLabel_en-US" xlink:label="lab_dei_EntityWellKnownSeasonedIssuer" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Well-known Seasoned Issuer</link:label>
    <link:label id="lab_dei_EntityWellKnownSeasonedIssuer_label_en-US" xlink:label="lab_dei_EntityWellKnownSeasonedIssuer" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Well-known Seasoned Issuer</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityWellKnownSeasonedIssuer" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityWellKnownSeasonedIssuer"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityWellKnownSeasonedIssuer" xlink:to="lab_dei_EntityWellKnownSeasonedIssuer" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionTermOfAgreement_019dd5f7-6198-7d23-bf6b-ef0572ee1f90_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionTermOfAgreement" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Agreement term</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionTermOfAgreement_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionTermOfAgreement" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Term Of Agreement</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionTermOfAgreement_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionTermOfAgreement" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Term Of Agreement</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionTermOfAgreement" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionTermOfAgreement"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionTermOfAgreement" xlink:to="lab_opi_RelatedPartyTransactionTermOfAgreement" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A4.500SeniorUnsecuredNotesMember_019dd0cc-a0c6-7958-ae90-ab7a2f964c0b_terseLabel_en-US" xlink:label="lab_opi_A4.500SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">4.500% Senior Unsecured Notes</link:label>
    <link:label id="lab_opi_A4.500SeniorUnsecuredNotesMember_label_en-US" xlink:label="lab_opi_A4.500SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">4.500% Senior Unsecured Notes [Member]</link:label>
    <link:label id="lab_opi_A4.500SeniorUnsecuredNotesMember_documentation_en-US" xlink:label="lab_opi_A4.500SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">4.500% Senior Unsecured Notes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A4.500SeniorUnsecuredNotesMember" xlink:href="opi-20251231.xsd#opi_A4.500SeniorUnsecuredNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A4.500SeniorUnsecuredNotesMember" xlink:to="lab_opi_A4.500SeniorUnsecuredNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LesseeOperatingLeaseNumberOfGovernmentTenantsWithTheRightToTerminateTheirLeases_019dbc7a-b287-7815-bf21-86fab7775193_terseLabel_en-US" xlink:label="lab_opi_LesseeOperatingLeaseNumberOfGovernmentTenantsWithTheRightToTerminateTheirLeases" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of government tenants with the right to terminate their leases</link:label>
    <link:label id="lab_opi_LesseeOperatingLeaseNumberOfGovernmentTenantsWithTheRightToTerminateTheirLeases_label_en-US" xlink:label="lab_opi_LesseeOperatingLeaseNumberOfGovernmentTenantsWithTheRightToTerminateTheirLeases" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Operating Lease, Number Of Government Tenants With The Right To Terminate Their Leases</link:label>
    <link:label id="lab_opi_LesseeOperatingLeaseNumberOfGovernmentTenantsWithTheRightToTerminateTheirLeases_documentation_en-US" xlink:label="lab_opi_LesseeOperatingLeaseNumberOfGovernmentTenantsWithTheRightToTerminateTheirLeases" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lessee, Operating Lease, Number Of Government Tenants With The Right To Terminate Their Leases</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LesseeOperatingLeaseNumberOfGovernmentTenantsWithTheRightToTerminateTheirLeases" xlink:href="opi-20251231.xsd#opi_LesseeOperatingLeaseNumberOfGovernmentTenantsWithTheRightToTerminateTheirLeases"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LesseeOperatingLeaseNumberOfGovernmentTenantsWithTheRightToTerminateTheirLeases" xlink:to="lab_opi_LesseeOperatingLeaseNumberOfGovernmentTenantsWithTheRightToTerminateTheirLeases" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A3400WestPlanoParkwayPlanoTXMember_019dbc7a-b1cb-7b56-bfef-936d8f4c75cd_terseLabel_en-US" xlink:label="lab_opi_A3400WestPlanoParkwayPlanoTXMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">3400 West Plano Parkway, Plano, TX</link:label>
    <link:label id="lab_opi_A3400WestPlanoParkwayPlanoTXMember_label_en-US" xlink:label="lab_opi_A3400WestPlanoParkwayPlanoTXMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">3400 West Plano Parkway, Plano, TX [Member]</link:label>
    <link:label id="lab_opi_A3400WestPlanoParkwayPlanoTXMember_documentation_en-US" xlink:label="lab_opi_A3400WestPlanoParkwayPlanoTXMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">3400 West Plano Parkway, Plano, TX [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A3400WestPlanoParkwayPlanoTXMember" xlink:href="opi-20251231.xsd#opi_A3400WestPlanoParkwayPlanoTXMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A3400WestPlanoParkwayPlanoTXMember" xlink:to="lab_opi_A3400WestPlanoParkwayPlanoTXMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_NumberOfJointVentures_019dbc7a-b287-789e-8f76-6c4015c61f65_terseLabel_en-US" xlink:label="lab_opi_NumberOfJointVentures" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of joint ventures</link:label>
    <link:label id="lab_opi_NumberOfJointVentures_label_en-US" xlink:label="lab_opi_NumberOfJointVentures" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number Of Joint Ventures</link:label>
    <link:label id="lab_opi_NumberOfJointVentures_documentation_en-US" xlink:label="lab_opi_NumberOfJointVentures" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Number Of Joint Ventures</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_NumberOfJointVentures" xlink:href="opi-20251231.xsd#opi_NumberOfJointVentures"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_NumberOfJointVentures" xlink:to="lab_opi_NumberOfJointVentures" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A1220EchelonParkwayJacksonMSMember_019dbc7a-b30c-7377-9f00-705ae9685d9a_terseLabel_en-US" xlink:label="lab_opi_A1220EchelonParkwayJacksonMSMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">1220 Echelon Parkway, Jackson, MS</link:label>
    <link:label id="lab_opi_A1220EchelonParkwayJacksonMSMember_label_en-US" xlink:label="lab_opi_A1220EchelonParkwayJacksonMSMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">1220 Echelon Parkway, Jackson, MS [Member]</link:label>
    <link:label id="lab_opi_A1220EchelonParkwayJacksonMSMember_documentation_en-US" xlink:label="lab_opi_A1220EchelonParkwayJacksonMSMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">1220 Echelon Parkway, Jackson, MS</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A1220EchelonParkwayJacksonMSMember" xlink:href="opi-20251231.xsd#opi_A1220EchelonParkwayJacksonMSMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A1220EchelonParkwayJacksonMSMember" xlink:to="lab_opi_A1220EchelonParkwayJacksonMSMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_TrdArrExpirationDate_terseLabel_en-US" xlink:label="lab_ecd_TrdArrExpirationDate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Expiration Date</link:label>
    <link:label id="lab_ecd_TrdArrExpirationDate_label_en-US" xlink:label="lab_ecd_TrdArrExpirationDate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Trading Arrangement Expiration Date</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_TrdArrExpirationDate" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_TrdArrExpirationDate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_TrdArrExpirationDate" xlink:to="lab_ecd_TrdArrExpirationDate" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAccumulatedDepreciation_019dbc7a-b287-7088-ae2b-eb4ccd6b34e5_negatedLabel_en-US" xlink:label="lab_us-gaap_RealEstateAccumulatedDepreciation" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Accumulated Depreciation</link:label>
    <link:label id="lab_us-gaap_RealEstateAccumulatedDepreciation_019dbc7a-b287-7553-bea8-99af0ca966c7_periodStartLabel_en-US" xlink:label="lab_us-gaap_RealEstateAccumulatedDepreciation" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Balance at the beginning of the period</link:label>
    <link:label id="lab_us-gaap_RealEstateAccumulatedDepreciation_019dbc7a-b287-7c16-be0a-eb5ad8d84d49_periodEndLabel_en-US" xlink:label="lab_us-gaap_RealEstateAccumulatedDepreciation" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Balance at the end of the period</link:label>
    <link:label id="lab_us-gaap_RealEstateAccumulatedDepreciation_label_en-US" xlink:label="lab_us-gaap_RealEstateAccumulatedDepreciation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAccumulatedDepreciation" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAccumulatedDepreciation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAccumulatedDepreciation" xlink:to="lab_us-gaap_RealEstateAccumulatedDepreciation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_019dbc7a-b286-7199-8eb5-01138fd1e960_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2030</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Asset, Expected Amortization, Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManageFeePercentOfGrossRevenues_019dbc7a-b287-752f-a7f5-29332d8162ab_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManageFeePercentOfGrossRevenues" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Base management fee, percent of gross revenues</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManageFeePercentOfGrossRevenues_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManageFeePercentOfGrossRevenues" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Base Manage Fee, Percent Of Gross Revenues</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManageFeePercentOfGrossRevenues_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManageFeePercentOfGrossRevenues" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Base Manage Fee, Percent Of Gross Revenues</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionBaseManageFeePercentOfGrossRevenues" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionBaseManageFeePercentOfGrossRevenues"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionBaseManageFeePercentOfGrossRevenues" xlink:to="lab_opi_RelatedPartyTransactionBaseManageFeePercentOfGrossRevenues" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RelatedPartyTransactionAmountsOfTransaction_019dbc7a-b1cb-7409-b57f-3de7d5038d5f_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionAmountsOfTransaction" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Transaction amount</link:label>
    <link:label id="lab_us-gaap_RelatedPartyTransactionAmountsOfTransaction_label_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionAmountsOfTransaction" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Amounts of Transaction</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionAmountsOfTransaction"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction" xlink:to="lab_us-gaap_RelatedPartyTransactionAmountsOfTransaction" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DebtInstrumentExitFeePercentage_019dd627-6f0c-7bb8-b694-7068c4788a44_terseLabel_en-US" xlink:label="lab_opi_DebtInstrumentExitFeePercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Exit fee percentage</link:label>
    <link:label id="lab_opi_DebtInstrumentExitFeePercentage_label_en-US" xlink:label="lab_opi_DebtInstrumentExitFeePercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Exit Fee Percentage</link:label>
    <link:label id="lab_opi_DebtInstrumentExitFeePercentage_documentation_en-US" xlink:label="lab_opi_DebtInstrumentExitFeePercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Exit Fee Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DebtInstrumentExitFeePercentage" xlink:href="opi-20251231.xsd#opi_DebtInstrumentExitFeePercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DebtInstrumentExitFeePercentage" xlink:to="lab_opi_DebtInstrumentExitFeePercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateCostOfRealEstateSold_019dbc7a-b287-7ecd-9678-7d7fdd537d09_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_RealEstateCostOfRealEstateSold" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Disposals</link:label>
    <link:label id="lab_us-gaap_RealEstateCostOfRealEstateSold_label_en-US" xlink:label="lab_us-gaap_RealEstateCostOfRealEstateSold" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Cost of Investment in Real Estate Sold</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateCostOfRealEstateSold" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateCostOfRealEstateSold"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateCostOfRealEstateSold" xlink:to="lab_us-gaap_RealEstateCostOfRealEstateSold" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionPercentageOfBaseBusinessManagementFeePayableInCommonShares_019dbc7a-b287-792c-b675-4050b4620393_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionPercentageOfBaseBusinessManagementFeePayableInCommonShares" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage of base business management fee payable in common shares</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionPercentageOfBaseBusinessManagementFeePayableInCommonShares_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionPercentageOfBaseBusinessManagementFeePayableInCommonShares" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction Percentage of Base Business Management Fee Payable in Common Shares</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionPercentageOfBaseBusinessManagementFeePayableInCommonShares_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionPercentageOfBaseBusinessManagementFeePayableInCommonShares" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the percentage of base business management fees payable in common shares.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionPercentageOfBaseBusinessManagementFeePayableInCommonShares" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionPercentageOfBaseBusinessManagementFeePayableInCommonShares"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionPercentageOfBaseBusinessManagementFeePayableInCommonShares" xlink:to="lab_opi_RelatedPartyTransactionPercentageOfBaseBusinessManagementFeePayableInCommonShares" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GeographicConcentrationRiskMember_019dbc7a-b1cb-7b8f-8bb8-029e0ee4b9e0_terseLabel_en-US" xlink:label="lab_us-gaap_GeographicConcentrationRiskMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Geographic Concentration Risk</link:label>
    <link:label id="lab_us-gaap_GeographicConcentrationRiskMember_label_en-US" xlink:label="lab_us-gaap_GeographicConcentrationRiskMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Geographic Concentration Risk [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeographicConcentrationRiskMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GeographicConcentrationRiskMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GeographicConcentrationRiskMember" xlink:to="lab_us-gaap_GeographicConcentrationRiskMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_AirlineCorporateCenterColonieNYMember_019dbc7a-b286-7f64-8199-4ce43d0338fc_terseLabel_en-US" xlink:label="lab_opi_AirlineCorporateCenterColonieNYMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Airline Corporate Center, Colonie, NY</link:label>
    <link:label id="lab_opi_AirlineCorporateCenterColonieNYMember_label_en-US" xlink:label="lab_opi_AirlineCorporateCenterColonieNYMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Airline Corporate Center, Colonie, NY [Member]</link:label>
    <link:label id="lab_opi_AirlineCorporateCenterColonieNYMember_documentation_en-US" xlink:label="lab_opi_AirlineCorporateCenterColonieNYMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents information pertaining to Airline Corporate Center, located in Colonie, New York.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_AirlineCorporateCenterColonieNYMember" xlink:href="opi-20251231.xsd#opi_AirlineCorporateCenterColonieNYMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_AirlineCorporateCenterColonieNYMember" xlink:to="lab_opi_AirlineCorporateCenterColonieNYMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_CompActuallyPaidVsNetIncomeTextBlock_terseLabel_en-US" xlink:label="lab_ecd_CompActuallyPaidVsNetIncomeTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Compensation Actually Paid vs. Net Income</link:label>
    <link:label id="lab_ecd_CompActuallyPaidVsNetIncomeTextBlock_label_en-US" xlink:label="lab_ecd_CompActuallyPaidVsNetIncomeTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Compensation Actually Paid vs. Net Income [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_CompActuallyPaidVsNetIncomeTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_CompActuallyPaidVsNetIncomeTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_CompActuallyPaidVsNetIncomeTextBlock" xlink:to="lab_ecd_CompActuallyPaidVsNetIncomeTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityCurrentReportingStatus_019dbc7a-b1cb-76aa-b102-e158ebe8c8a3_terseLabel_en-US" xlink:label="lab_dei_EntityCurrentReportingStatus" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Current Reporting Status</link:label>
    <link:label id="lab_dei_EntityCurrentReportingStatus_label_en-US" xlink:label="lab_dei_EntityCurrentReportingStatus" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Current Reporting Status</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityCurrentReportingStatus"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityCurrentReportingStatus" xlink:to="lab_dei_EntityCurrentReportingStatus" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_NumberOfBorrowersWithWaiverAgreements_019e08bf-3ca1-7f8c-965a-4d1b771d21ef_terseLabel_en-US" xlink:label="lab_opi_NumberOfBorrowersWithWaiverAgreements" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of borrowers that have entered waiver agreements</link:label>
    <link:label id="lab_opi_NumberOfBorrowersWithWaiverAgreements_label_en-US" xlink:label="lab_opi_NumberOfBorrowersWithWaiverAgreements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number Of Borrowers With Waiver Agreements</link:label>
    <link:label id="lab_opi_NumberOfBorrowersWithWaiverAgreements_documentation_en-US" xlink:label="lab_opi_NumberOfBorrowersWithWaiverAgreements" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Number Of Borrowers With Waiver Agreements</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_NumberOfBorrowersWithWaiverAgreements" xlink:href="opi-20251231.xsd#opi_NumberOfBorrowersWithWaiverAgreements"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_NumberOfBorrowersWithWaiverAgreements" xlink:to="lab_opi_NumberOfBorrowersWithWaiverAgreements" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AwardsCloseToMnpiDiscTable_terseLabel_en-US" xlink:label="lab_ecd_AwardsCloseToMnpiDiscTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Awards Close in Time to MNPI Disclosures</link:label>
    <link:label id="lab_ecd_AwardsCloseToMnpiDiscTable_label_en-US" xlink:label="lab_ecd_AwardsCloseToMnpiDiscTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Awards Close in Time to MNPI Disclosures [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AwardsCloseToMnpiDiscTable" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AwardsCloseToMnpiDiscTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AwardsCloseToMnpiDiscTable" xlink:to="lab_ecd_AwardsCloseToMnpiDiscTable" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ConsolidatedEntitiesDomain_019dd081-dfd7-76a6-a53d-391702443fad_terseLabel_en-US" xlink:label="lab_srt_ConsolidatedEntitiesDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Consolidated Entities [Domain]</link:label>
    <link:label id="lab_srt_ConsolidatedEntitiesDomain_label_en-US" xlink:label="lab_srt_ConsolidatedEntitiesDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Consolidated Entities [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ConsolidatedEntitiesDomain" xlink:to="lab_srt_ConsolidatedEntitiesDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageHistoricalCostOfRealEstateInvestmentsExcludingTransferredAssetsForInvestmentsUptoSpecifiedAmount_019dbc7a-b1cb-787c-b417-0bf4afa11af6_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageHistoricalCostOfRealEstateInvestmentsExcludingTransferredAssetsForInvestmentsUptoSpecifiedAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Base management fee payable as percentage of average historical cost of real estate investments</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageHistoricalCostOfRealEstateInvestmentsExcludingTransferredAssetsForInvestmentsUptoSpecifiedAmount_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageHistoricalCostOfRealEstateInvestmentsExcludingTransferredAssetsForInvestmentsUptoSpecifiedAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction Base Management Fee Payable As Percentage Of Average Historical Cost Of Real Estate Investments Excluding Transferred Assets For Investments Upto Specified Amount</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageHistoricalCostOfRealEstateInvestmentsExcludingTransferredAssetsForInvestmentsUptoSpecifiedAmount_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageHistoricalCostOfRealEstateInvestmentsExcludingTransferredAssetsForInvestmentsUptoSpecifiedAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the base management fees payable as a percentage of average historical cost of real estate investments, excluding transferred assets for investments up to specified amount.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageHistoricalCostOfRealEstateInvestmentsExcludingTransferredAssetsForInvestmentsUptoSpecifiedAmount" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageHistoricalCostOfRealEstateInvestmentsExcludingTransferredAssetsForInvestmentsUptoSpecifiedAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageHistoricalCostOfRealEstateInvestmentsExcludingTransferredAssetsForInvestmentsUptoSpecifiedAmount" xlink:to="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageHistoricalCostOfRealEstateInvestmentsExcludingTransferredAssetsForInvestmentsUptoSpecifiedAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_OnePrimericaParkwayDuluthGAMember_019dbc7a-b1cb-7a35-ba6b-ac5a87f0da1f_terseLabel_en-US" xlink:label="lab_opi_OnePrimericaParkwayDuluthGAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">One Primerica Parkway, Duluth, GA</link:label>
    <link:label id="lab_opi_OnePrimericaParkwayDuluthGAMember_label_en-US" xlink:label="lab_opi_OnePrimericaParkwayDuluthGAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">One Primerica Parkway, Duluth, GA [Member]</link:label>
    <link:label id="lab_opi_OnePrimericaParkwayDuluthGAMember_documentation_en-US" xlink:label="lab_opi_OnePrimericaParkwayDuluthGAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">One Primerica Parkway, Duluth, GA [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_OnePrimericaParkwayDuluthGAMember" xlink:href="opi-20251231.xsd#opi_OnePrimericaParkwayDuluthGAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_OnePrimericaParkwayDuluthGAMember" xlink:to="lab_opi_OnePrimericaParkwayDuluthGAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_TransactionDomain_019dbc7a-b287-78bd-a19a-5d47f6c3b0b0_terseLabel_en-US" xlink:label="lab_us-gaap_TransactionDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Transaction [Domain]</link:label>
    <link:label id="lab_us-gaap_TransactionDomain_label_en-US" xlink:label="lab_us-gaap_TransactionDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Transaction [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransactionDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TransactionDomain" xlink:to="lab_us-gaap_TransactionDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementOfFinancialPositionAbstract_019dbc7a-b287-7fe7-973d-7b48b781ab2e_terseLabel_en-US" xlink:label="lab_us-gaap_StatementOfFinancialPositionAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statement of Financial Position [Abstract]</link:label>
    <link:label id="lab_us-gaap_StatementOfFinancialPositionAbstract_label_en-US" xlink:label="lab_us-gaap_StatementOfFinancialPositionAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Financial Position [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfFinancialPositionAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementOfFinancialPositionAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract" xlink:to="lab_us-gaap_StatementOfFinancialPositionAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_ExecutiveCategoryAxis_terseLabel_en-US" xlink:label="lab_ecd_ExecutiveCategoryAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Executive Category:</link:label>
    <link:label id="lab_ecd_ExecutiveCategoryAxis_label_en-US" xlink:label="lab_ecd_ExecutiveCategoryAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Executive Category [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_ExecutiveCategoryAxis" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_ExecutiveCategoryAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_ExecutiveCategoryAxis" xlink:to="lab_ecd_ExecutiveCategoryAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod_019dbc7a-b287-77d9-acf6-d5ab9aa3533b_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common share grants (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Net of Forfeitures</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_MortgageLoansOnRealEstate_019dbc7a-b1cb-7fbe-abe6-15b86d480b2d_terseLabel_en-US" xlink:label="lab_us-gaap_MortgageLoansOnRealEstate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mortgage debt, net</link:label>
    <link:label id="lab_us-gaap_MortgageLoansOnRealEstate_label_en-US" xlink:label="lab_us-gaap_MortgageLoansOnRealEstate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageLoansOnRealEstate" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MortgageLoansOnRealEstate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MortgageLoansOnRealEstate" xlink:to="lab_us-gaap_MortgageLoansOnRealEstate" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InterestExpense_019dbc7a-b287-7103-a35f-36eb25ba1d1c_negatedLabel_en-US" xlink:label="lab_us-gaap_InterestExpense" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Interest expense (including net amortization of debt premiums, discounts and issuance costs of $40,825 and $13,463, respectively)</link:label>
    <link:label id="lab_us-gaap_InterestExpense_019dd086-b1c0-7619-bb61-92c7f78ceed6_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_InterestExpense" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Interest expense (including net amortization of debt premiums, discounts and issuance costs of $39,898)</link:label>
    <link:label id="lab_us-gaap_InterestExpense_label_en-US" xlink:label="lab_us-gaap_InterestExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Expense, Operating and Nonoperating</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestExpense" xlink:to="lab_us-gaap_InterestExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_CurrentFiscalYearEndDate_019dbc7a-b1cb-7045-98a7-9d382e4d2176_terseLabel_en-US" xlink:label="lab_dei_CurrentFiscalYearEndDate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Current Fiscal Year End Date</link:label>
    <link:label id="lab_dei_CurrentFiscalYearEndDate_label_en-US" xlink:label="lab_dei_CurrentFiscalYearEndDate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Current Fiscal Year End Date</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_CurrentFiscalYearEndDate" xlink:to="lab_dei_CurrentFiscalYearEndDate" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019dbc7a-b1cb-7977-a4aa-949c9f15a70b_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Major Class Name [Domain]</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Major Class Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtConversionConvertedInstrumentAmount1_019dd5e9-a05f-75cb-b846-8217fc54fb35_verboseLabel_en-US" xlink:label="lab_us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Debt converted</link:label>
    <link:label id="lab_us-gaap_DebtConversionConvertedInstrumentAmount1_019dbc7a-b287-7ac0-b39b-0d6ef3ca751b_terseLabel_en-US" xlink:label="lab_us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate Principal Amount of Notes Delivered</link:label>
    <link:label id="lab_us-gaap_DebtConversionConvertedInstrumentAmount1_label_en-US" xlink:label="lab_us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Conversion, Converted Instrument, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtConversionConvertedInstrumentAmount1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:to="lab_us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_AcquiredLeaseAmortizationPeriod_019dbc7a-b1cb-79a4-9532-d8806fa03a40_terseLabel_en-US" xlink:label="lab_opi_AcquiredLeaseAmortizationPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Acquired lease amortization period</link:label>
    <link:label id="lab_opi_AcquiredLeaseAmortizationPeriod_label_en-US" xlink:label="lab_opi_AcquiredLeaseAmortizationPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Acquired Lease Amortization Period</link:label>
    <link:label id="lab_opi_AcquiredLeaseAmortizationPeriod_documentation_en-US" xlink:label="lab_opi_AcquiredLeaseAmortizationPeriod" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the acquired lease amortization period.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_AcquiredLeaseAmortizationPeriod" xlink:href="opi-20251231.xsd#opi_AcquiredLeaseAmortizationPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_AcquiredLeaseAmortizationPeriod" xlink:to="lab_opi_AcquiredLeaseAmortizationPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019dbc7a-b1cb-70b4-bce0-6d24383926fa_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted Average Grant Date Fair Value</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_019dbc7a-b286-72e2-b8c0-d4f431a66106_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Shares available for issuance under plan (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfRealEstatePropertiesTable_019dbc7a-b1cb-7afc-b0cc-2f1c65cccc9b_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfRealEstatePropertiesTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate Property, Ownership [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfRealEstatePropertiesTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfRealEstatePropertiesTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Property, Ownership [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRealEstatePropertiesTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfRealEstatePropertiesTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfRealEstatePropertiesTable" xlink:to="lab_us-gaap_ScheduleOfRealEstatePropertiesTable" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_EqtyAwrdsAdjsExclgValRprtdInSummryCompstnTblMember_terseLabel_en-US" xlink:label="lab_ecd_EqtyAwrdsAdjsExclgValRprtdInSummryCompstnTblMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity Awards Adjustments, Excluding Value Reported in Compensation Table</link:label>
    <link:label id="lab_ecd_EqtyAwrdsAdjsExclgValRprtdInSummryCompstnTblMember_label_en-US" xlink:label="lab_ecd_EqtyAwrdsAdjsExclgValRprtdInSummryCompstnTblMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_EqtyAwrdsAdjsExclgValRprtdInSummryCompstnTblMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_EqtyAwrdsAdjsExclgValRprtdInSummryCompstnTblMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_EqtyAwrdsAdjsExclgValRprtdInSummryCompstnTblMember" xlink:to="lab_ecd_EqtyAwrdsAdjsExclgValRprtdInSummryCompstnTblMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_USGovernmentStateGovernmentsAndOtherGovernmentMember_019dbc7a-b1cb-7ab4-b8be-c28fc47e8ef8_terseLabel_en-US" xlink:label="lab_opi_USGovernmentStateGovernmentsAndOtherGovernmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">U S Government, State Governments, and Other Governments</link:label>
    <link:label id="lab_opi_USGovernmentStateGovernmentsAndOtherGovernmentMember_label_en-US" xlink:label="lab_opi_USGovernmentStateGovernmentsAndOtherGovernmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">U S Government State Governments And Other Government [Member]</link:label>
    <link:label id="lab_opi_USGovernmentStateGovernmentsAndOtherGovernmentMember_documentation_en-US" xlink:label="lab_opi_USGovernmentStateGovernmentsAndOtherGovernmentMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the U.S. Government, state governments and Other Government, combined.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_USGovernmentStateGovernmentsAndOtherGovernmentMember" xlink:href="opi-20251231.xsd#opi_USGovernmentStateGovernmentsAndOtherGovernmentMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_USGovernmentStateGovernmentsAndOtherGovernmentMember" xlink:to="lab_opi_USGovernmentStateGovernmentsAndOtherGovernmentMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A8900GrandOakCircleTampaFLMember_019dbc7a-b286-7a0f-a71c-ab33f19b5c7c_terseLabel_en-US" xlink:label="lab_opi_A8900GrandOakCircleTampaFLMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">8900 Grand Oak Circle, Tampa, FL</link:label>
    <link:label id="lab_opi_A8900GrandOakCircleTampaFLMember_label_en-US" xlink:label="lab_opi_A8900GrandOakCircleTampaFLMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">8900 Grand Oak Circle, Tampa, FL [Member]</link:label>
    <link:label id="lab_opi_A8900GrandOakCircleTampaFLMember_documentation_en-US" xlink:label="lab_opi_A8900GrandOakCircleTampaFLMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">8900 Grand Oak Circle, Tampa, FL</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A8900GrandOakCircleTampaFLMember" xlink:href="opi-20251231.xsd#opi_A8900GrandOakCircleTampaFLMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A8900GrandOakCircleTampaFLMember" xlink:to="lab_opi_A8900GrandOakCircleTampaFLMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LongTermDebtReorganizedCommonStockPercentageReceivable_019dff2d-4b5e-7f59-8f32-1edcb9419123_terseLabel_en-US" xlink:label="lab_opi_LongTermDebtReorganizedCommonStockPercentageReceivable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage of equity receivable</link:label>
    <link:label id="lab_opi_LongTermDebtReorganizedCommonStockPercentageReceivable_label_en-US" xlink:label="lab_opi_LongTermDebtReorganizedCommonStockPercentageReceivable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Reorganized Common Stock, Percentage Receivable</link:label>
    <link:label id="lab_opi_LongTermDebtReorganizedCommonStockPercentageReceivable_documentation_en-US" xlink:label="lab_opi_LongTermDebtReorganizedCommonStockPercentageReceivable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Reorganized Common Stock, Percentage Receivable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LongTermDebtReorganizedCommonStockPercentageReceivable" xlink:href="opi-20251231.xsd#opi_LongTermDebtReorganizedCommonStockPercentageReceivable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LongTermDebtReorganizedCommonStockPercentageReceivable" xlink:to="lab_opi_LongTermDebtReorganizedCommonStockPercentageReceivable" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_OperatingLeasesWeightedAverageLeaseTerm_019dbc7a-b30c-7a8c-8f87-07c39ab2af73_terseLabel_en-US" xlink:label="lab_opi_OperatingLeasesWeightedAverageLeaseTerm" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted average lease term</link:label>
    <link:label id="lab_opi_OperatingLeasesWeightedAverageLeaseTerm_label_en-US" xlink:label="lab_opi_OperatingLeasesWeightedAverageLeaseTerm" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Leases Weighted Average Lease Term</link:label>
    <link:label id="lab_opi_OperatingLeasesWeightedAverageLeaseTerm_documentation_en-US" xlink:label="lab_opi_OperatingLeasesWeightedAverageLeaseTerm" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the weighted average lease term of operating leases.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_OperatingLeasesWeightedAverageLeaseTerm" xlink:href="opi-20251231.xsd#opi_OperatingLeasesWeightedAverageLeaseTerm"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_OperatingLeasesWeightedAverageLeaseTerm" xlink:to="lab_opi_OperatingLeasesWeightedAverageLeaseTerm" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueByBalanceSheetGroupingTable_019dbc7a-b286-7f96-893d-9e1a5c5d6fcd_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueByBalanceSheetGroupingTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair Value, by Balance Sheet Grouping [Table]</link:label>
    <link:label id="lab_us-gaap_FairValueByBalanceSheetGroupingTable_label_en-US" xlink:label="lab_us-gaap_FairValueByBalanceSheetGroupingTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, by Balance Sheet Grouping [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable" xlink:to="lab_us-gaap_FairValueByBalanceSheetGroupingTable" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A145RioRoblesDriveSanJoseCAMember_019dbc7a-b286-73c6-bbfd-34c917638926_terseLabel_en-US" xlink:label="lab_opi_A145RioRoblesDriveSanJoseCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">145 Rio Robles Drive, San Jose, CA</link:label>
    <link:label id="lab_opi_A145RioRoblesDriveSanJoseCAMember_label_en-US" xlink:label="lab_opi_A145RioRoblesDriveSanJoseCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">145 Rio Robles Drive, San Jose, CA [Member]</link:label>
    <link:label id="lab_opi_A145RioRoblesDriveSanJoseCAMember_documentation_en-US" xlink:label="lab_opi_A145RioRoblesDriveSanJoseCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">145 Rio Robles Drive, San Jose, CA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A145RioRoblesDriveSanJoseCAMember" xlink:href="opi-20251231.xsd#opi_A145RioRoblesDriveSanJoseCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A145RioRoblesDriveSanJoseCAMember" xlink:to="lab_opi_A145RioRoblesDriveSanJoseCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_019dbc7a-b287-732f-a5aa-fd946069b7bf_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2027</link:label>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Maturity, Year Two</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ReorganizationItemsTableTextBlock_019dd0b7-ab14-77c3-8ba7-5b9bae382788_terseLabel_en-US" xlink:label="lab_opi_ReorganizationItemsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Reorganization Items</link:label>
    <link:label id="lab_opi_ReorganizationItemsTableTextBlock_label_en-US" xlink:label="lab_opi_ReorganizationItemsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reorganization Items [Table Text Block]</link:label>
    <link:label id="lab_opi_ReorganizationItemsTableTextBlock_documentation_en-US" xlink:label="lab_opi_ReorganizationItemsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Reorganization Items</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ReorganizationItemsTableTextBlock" xlink:href="opi-20251231.xsd#opi_ReorganizationItemsTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ReorganizationItemsTableTextBlock" xlink:to="lab_opi_ReorganizationItemsTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_TempeAZMember_019dbc7a-b286-7906-b192-2fdfd0583716_terseLabel_en-US" xlink:label="lab_opi_TempeAZMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tempe, AZ</link:label>
    <link:label id="lab_opi_TempeAZMember_label_en-US" xlink:label="lab_opi_TempeAZMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tempe, AZ [Member]</link:label>
    <link:label id="lab_opi_TempeAZMember_documentation_en-US" xlink:label="lab_opi_TempeAZMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tempe, AZ</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_TempeAZMember" xlink:href="opi-20251231.xsd#opi_TempeAZMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_TempeAZMember" xlink:to="lab_opi_TempeAZMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeasesTextBlock_019dbc7a-b1cb-7445-bf2a-78848b5d8154_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeasesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Leases</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeasesTextBlock_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeasesTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Operating Leases [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeasesTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeasesTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeasesTextBlock" xlink:to="lab_us-gaap_LesseeOperatingLeasesTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_019dbc7a-b287-76ff-90f6-c7a114f500d8_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash (used in) provided by financing activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Provided by (Used in) Financing Activity, Including Discontinued Operation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_MeasureAxis_terseLabel_en-US" xlink:label="lab_ecd_MeasureAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Measure:</link:label>
    <link:label id="lab_ecd_MeasureAxis_label_en-US" xlink:label="lab_ecd_MeasureAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Measure [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_MeasureAxis" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_MeasureAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_MeasureAxis" xlink:to="lab_ecd_MeasureAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_019dbc7a-b1cb-7800-b49f-d63139598268_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Thereafter</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Asset, Expected Amortization, after Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredRentReceivablesNet_019dbc7a-b1cb-7d8c-bed5-99ac7178df0d_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredRentReceivablesNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Straight line rent receivables</link:label>
    <link:label id="lab_us-gaap_DeferredRentReceivablesNet_label_en-US" xlink:label="lab_us-gaap_DeferredRentReceivablesNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Rent Receivables, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredRentReceivablesNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredRentReceivablesNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredRentReceivablesNet" xlink:to="lab_us-gaap_DeferredRentReceivablesNet" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DisposalGroupClassificationDomain_019dbc7a-b287-7551-bf9d-4de88cfbbebd_terseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupClassificationDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Disposal Group Classification [Domain]</link:label>
    <link:label id="lab_us-gaap_DisposalGroupClassificationDomain_label_en-US" xlink:label="lab_us-gaap_DisposalGroupClassificationDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group Classification [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain" xlink:to="lab_us-gaap_DisposalGroupClassificationDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureTextBlock_019dbc7a-b1cb-7791-b523-2514895d9d51_terseLabel_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION</link:label>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureTextBlock_label_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RealEstateAndAccumulatedDepreciationDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDisclosureTextBlock" xlink:to="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfFreshStartAdjustmentsTextBlock_019dd07e-5f79-774d-9394-38a9605a4346_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfFreshStartAdjustmentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Financial Statements included in Chapter 11 Cases</link:label>
    <link:label id="lab_us-gaap_ScheduleOfFreshStartAdjustmentsTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfFreshStartAdjustmentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reorganization, Chapter 11 [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFreshStartAdjustmentsTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfFreshStartAdjustmentsTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfFreshStartAdjustmentsTextBlock" xlink:to="lab_us-gaap_ScheduleOfFreshStartAdjustmentsTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_PvpTableTextBlock_terseLabel_en-US" xlink:label="lab_ecd_PvpTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pay vs Performance Disclosure, Table</link:label>
    <link:label id="lab_ecd_PvpTableTextBlock_label_en-US" xlink:label="lab_ecd_PvpTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pay vs Performance [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_PvpTableTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_PvpTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_PvpTableTextBlock" xlink:to="lab_ecd_PvpTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLandAndBuildingsAndImprovementsAbstract_019dbc7a-b287-7cb5-a58e-e188150442ef_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLandAndBuildingsAndImprovementsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cost amount carried at Close of Period</link:label>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLandAndBuildingsAndImprovementsAbstract_label_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLandAndBuildingsAndImprovementsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Gross [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLandAndBuildingsAndImprovementsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLandAndBuildingsAndImprovementsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLandAndBuildingsAndImprovementsAbstract" xlink:to="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLandAndBuildingsAndImprovementsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A118512491387S.VinnellWayBoiseIDMember_019dbc7a-b287-7833-a5f9-7b9d5fa20cdd_terseLabel_en-US" xlink:label="lab_opi_A118512491387S.VinnellWayBoiseIDMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">1185, 1249 &amp; 1387 S. Vinnell Way, Boise, ID</link:label>
    <link:label id="lab_opi_A118512491387S.VinnellWayBoiseIDMember_label_en-US" xlink:label="lab_opi_A118512491387S.VinnellWayBoiseIDMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">1185, 1249 &amp; 1387 S. Vinnell Way, Boise, ID [Member]</link:label>
    <link:label id="lab_opi_A118512491387S.VinnellWayBoiseIDMember_documentation_en-US" xlink:label="lab_opi_A118512491387S.VinnellWayBoiseIDMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">1185, 1249 &amp; 1387 S. Vinnell Way, Boise, ID</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A118512491387S.VinnellWayBoiseIDMember" xlink:href="opi-20251231.xsd#opi_A118512491387S.VinnellWayBoiseIDMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A118512491387S.VinnellWayBoiseIDMember" xlink:to="lab_opi_A118512491387S.VinnellWayBoiseIDMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_ForgoneRecoveryDueToViolationOfHomeCountryLawAmt_terseLabel_en-US" xlink:label="lab_ecd_ForgoneRecoveryDueToViolationOfHomeCountryLawAmt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Forgone Recovery due to Violation of Home Country Law, Amount</link:label>
    <link:label id="lab_ecd_ForgoneRecoveryDueToViolationOfHomeCountryLawAmt_label_en-US" xlink:label="lab_ecd_ForgoneRecoveryDueToViolationOfHomeCountryLawAmt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Forgone Recovery due to Violation of Home Country Law, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_ForgoneRecoveryDueToViolationOfHomeCountryLawAmt" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_ForgoneRecoveryDueToViolationOfHomeCountryLawAmt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_ForgoneRecoveryDueToViolationOfHomeCountryLawAmt" xlink:to="lab_ecd_ForgoneRecoveryDueToViolationOfHomeCountryLawAmt" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityTaxIdentificationNumber_019dbc7a-b30c-7009-a404-f1805113098e_terseLabel_en-US" xlink:label="lab_dei_EntityTaxIdentificationNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Tax Identification Number</link:label>
    <link:label id="lab_dei_EntityTaxIdentificationNumber_label_en-US" xlink:label="lab_dei_EntityTaxIdentificationNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Tax Identification Number</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityTaxIdentificationNumber" xlink:to="lab_dei_EntityTaxIdentificationNumber" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_AssetManagementAmortizationMember_019dd0c6-b5cb-7fa3-87b1-0bc473ab9f33_terseLabel_en-US" xlink:label="lab_opi_AssetManagementAmortizationMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Asset Management Amortization</link:label>
    <link:label id="lab_opi_AssetManagementAmortizationMember_label_en-US" xlink:label="lab_opi_AssetManagementAmortizationMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Asset Management Amortization [Member]</link:label>
    <link:label id="lab_opi_AssetManagementAmortizationMember_documentation_en-US" xlink:label="lab_opi_AssetManagementAmortizationMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Asset Management Amortization</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_AssetManagementAmortizationMember" xlink:href="opi-20251231.xsd#opi_AssetManagementAmortizationMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_AssetManagementAmortizationMember" xlink:to="lab_opi_AssetManagementAmortizationMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NumberOfRealEstateProperties_019dbc7a-b287-7307-8372-2e46eb716c78_terseLabel_en-US" xlink:label="lab_us-gaap_NumberOfRealEstateProperties" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of Properties (in properties)</link:label>
    <link:label id="lab_us-gaap_NumberOfRealEstateProperties_label_en-US" xlink:label="lab_us-gaap_NumberOfRealEstateProperties" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Real Estate Properties</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfRealEstateProperties" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NumberOfRealEstateProperties"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NumberOfRealEstateProperties" xlink:to="lab_us-gaap_NumberOfRealEstateProperties" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodCommittedButUnspentTenantRelatedObligations_019dbc7a-b287-78da-ad60-16c2c8c4ec1e_terseLabel_en-US" xlink:label="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodCommittedButUnspentTenantRelatedObligations" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating leases committed expenditures on leases executed in period committed but unspent tenant related obligations</link:label>
    <link:label id="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodCommittedButUnspentTenantRelatedObligations_label_en-US" xlink:label="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodCommittedButUnspentTenantRelatedObligations" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Leases Committed Expenditures on Leases Executed in Period Committed but Unspent Tenant Related Obligations</link:label>
    <link:label id="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodCommittedButUnspentTenantRelatedObligations_documentation_en-US" xlink:label="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodCommittedButUnspentTenantRelatedObligations" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents committed but unspent tenant related obligations based on executed operating leases as of the balance sheet date.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodCommittedButUnspentTenantRelatedObligations" xlink:href="opi-20251231.xsd#opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodCommittedButUnspentTenantRelatedObligations"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodCommittedButUnspentTenantRelatedObligations" xlink:to="lab_opi_OperatingLeasesCommittedExpendituresOnLeasesExecutedInPeriodCommittedButUnspentTenantRelatedObligations" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockSharesIssued_019dbc7a-b287-7ade-9eb1-d0a8e463d112_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesIssued" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common shares of beneficial interest, shares issued (in shares)</link:label>
    <link:label id="lab_us-gaap_CommonStockSharesIssued_label_en-US" xlink:label="lab_us-gaap_CommonStockSharesIssued" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock, Shares, Issued</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockSharesIssued" xlink:to="lab_us-gaap_CommonStockSharesIssued" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_019dbc7a-b30c-7b96-b3bf-37191a842abd_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2029</link:label>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Maturity, Year Four</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionWindowAfterChangeOfControlPriorWrittenNoticeForTerminationOfPropertyManagementAgreementByRelatedParty_019dbc7a-b1cb-7697-b2ca-d54c4c051bfe_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionWindowAfterChangeOfControlPriorWrittenNoticeForTerminationOfPropertyManagementAgreementByRelatedParty" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Window for written notice after change of control</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionWindowAfterChangeOfControlPriorWrittenNoticeForTerminationOfPropertyManagementAgreementByRelatedParty_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionWindowAfterChangeOfControlPriorWrittenNoticeForTerminationOfPropertyManagementAgreementByRelatedParty" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction Window After Change Of Control Prior Written Notice For Termination Of Property Management Agreement By Related Party</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionWindowAfterChangeOfControlPriorWrittenNoticeForTerminationOfPropertyManagementAgreementByRelatedParty_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionWindowAfterChangeOfControlPriorWrittenNoticeForTerminationOfPropertyManagementAgreementByRelatedParty" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the window after a change in control to provide notice for termination of property management agreement by the related party.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionWindowAfterChangeOfControlPriorWrittenNoticeForTerminationOfPropertyManagementAgreementByRelatedParty" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionWindowAfterChangeOfControlPriorWrittenNoticeForTerminationOfPropertyManagementAgreementByRelatedParty"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionWindowAfterChangeOfControlPriorWrittenNoticeForTerminationOfPropertyManagementAgreementByRelatedParty" xlink:to="lab_opi_RelatedPartyTransactionWindowAfterChangeOfControlPriorWrittenNoticeForTerminationOfPropertyManagementAgreementByRelatedParty" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A16001NorthDallasParkwayAddisonTXMember_019dbc7a-b287-77ac-8c9d-8ea1d7b8436a_terseLabel_en-US" xlink:label="lab_opi_A16001NorthDallasParkwayAddisonTXMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">16001 North Dallas Parkway, Addison, TX</link:label>
    <link:label id="lab_opi_A16001NorthDallasParkwayAddisonTXMember_label_en-US" xlink:label="lab_opi_A16001NorthDallasParkwayAddisonTXMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">16001 North Dallas Parkway, Addison, TX [Member]</link:label>
    <link:label id="lab_opi_A16001NorthDallasParkwayAddisonTXMember_documentation_en-US" xlink:label="lab_opi_A16001NorthDallasParkwayAddisonTXMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">16001 North Dallas Parkway, Addison, TX [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A16001NorthDallasParkwayAddisonTXMember" xlink:href="opi-20251231.xsd#opi_A16001NorthDallasParkwayAddisonTXMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A16001NorthDallasParkwayAddisonTXMember" xlink:to="lab_opi_A16001NorthDallasParkwayAddisonTXMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_FlorenceKYMember_019dbc7a-b287-7e1a-899a-11c12e01ede3_terseLabel_en-US" xlink:label="lab_opi_FlorenceKYMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Florence, KY</link:label>
    <link:label id="lab_opi_FlorenceKYMember_label_en-US" xlink:label="lab_opi_FlorenceKYMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Florence, KY [Member]</link:label>
    <link:label id="lab_opi_FlorenceKYMember_documentation_en-US" xlink:label="lab_opi_FlorenceKYMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Florence, KY</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_FlorenceKYMember" xlink:href="opi-20251231.xsd#opi_FlorenceKYMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_FlorenceKYMember" xlink:to="lab_opi_FlorenceKYMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ShareBasedPaymentArrangementTrancheFourMember_019dbc7a-b287-798c-a05a-592754ccebae_terseLabel_en-US" xlink:label="lab_opi_ShareBasedPaymentArrangementTrancheFourMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement, Tranche 4</link:label>
    <link:label id="lab_opi_ShareBasedPaymentArrangementTrancheFourMember_label_en-US" xlink:label="lab_opi_ShareBasedPaymentArrangementTrancheFourMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement, Tranche Four [Member]</link:label>
    <link:label id="lab_opi_ShareBasedPaymentArrangementTrancheFourMember_documentation_en-US" xlink:label="lab_opi_ShareBasedPaymentArrangementTrancheFourMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement, Tranche Four</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ShareBasedPaymentArrangementTrancheFourMember" xlink:href="opi-20251231.xsd#opi_ShareBasedPaymentArrangementTrancheFourMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ShareBasedPaymentArrangementTrancheFourMember" xlink:to="lab_opi_ShareBasedPaymentArrangementTrancheFourMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A8.000SeniorUnsecuredNotesMember_019dbc7a-b287-7428-b46c-e52e87457e3a_terseLabel_en-US" xlink:label="lab_opi_A8.000SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior priority guaranteed unsecured notes, 8.000% interest rate, due in 2030</link:label>
    <link:label id="lab_opi_A8.000SeniorUnsecuredNotesMember_label_en-US" xlink:label="lab_opi_A8.000SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">8.000% Senior Unsecured Notes [Member]</link:label>
    <link:label id="lab_opi_A8.000SeniorUnsecuredNotesMember_documentation_en-US" xlink:label="lab_opi_A8.000SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">8.000% Senior Unsecured Notes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A8.000SeniorUnsecuredNotesMember" xlink:href="opi-20251231.xsd#opi_A8.000SeniorUnsecuredNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A8.000SeniorUnsecuredNotesMember" xlink:to="lab_opi_A8.000SeniorUnsecuredNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityPublicFloat_019dbc7a-b287-7ea6-8266-90539c6d97dc_terseLabel_en-US" xlink:label="lab_dei_EntityPublicFloat" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Public Float</link:label>
    <link:label id="lab_dei_EntityPublicFloat_label_en-US" xlink:label="lab_dei_EntityPublicFloat" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Public Float</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityPublicFloat" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityPublicFloat"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityPublicFloat" xlink:to="lab_dei_EntityPublicFloat" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_TradingArrAxis_terseLabel_en-US" xlink:label="lab_ecd_TradingArrAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Trading Arrangement:</link:label>
    <link:label id="lab_ecd_TradingArrAxis_label_en-US" xlink:label="lab_ecd_TradingArrAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Trading Arrangement [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_TradingArrAxis" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_TradingArrAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_TradingArrAxis" xlink:to="lab_ecd_TradingArrAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_TotalShareholderRtnAmt_terseLabel_en-US" xlink:label="lab_ecd_TotalShareholderRtnAmt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total Shareholder Return Amount</link:label>
    <link:label id="lab_ecd_TotalShareholderRtnAmt_label_en-US" xlink:label="lab_ecd_TotalShareholderRtnAmt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Total Shareholder Return Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_TotalShareholderRtnAmt" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_TotalShareholderRtnAmt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_TotalShareholderRtnAmt" xlink:to="lab_ecd_TotalShareholderRtnAmt" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_AmortizationOfDeferredLeasingCosts_019dbc7a-b286-75a0-ad04-80de725bc935_terseLabel_en-US" xlink:label="lab_opi_AmortizationOfDeferredLeasingCosts" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amortization of deferred leasing costs</link:label>
    <link:label id="lab_opi_AmortizationOfDeferredLeasingCosts_label_en-US" xlink:label="lab_opi_AmortizationOfDeferredLeasingCosts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amortization of Deferred Leasing Costs</link:label>
    <link:label id="lab_opi_AmortizationOfDeferredLeasingCosts_documentation_en-US" xlink:label="lab_opi_AmortizationOfDeferredLeasingCosts" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amortization of Deferred Leasing Costs</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_AmortizationOfDeferredLeasingCosts" xlink:href="opi-20251231.xsd#opi_AmortizationOfDeferredLeasingCosts"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_AmortizationOfDeferredLeasingCosts" xlink:to="lab_opi_AmortizationOfDeferredLeasingCosts" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A11020SunCenterDriveRanchoCordovaCAMember_019dbc7a-b1cb-7bb5-bbbc-4cc27ac606f2_terseLabel_en-US" xlink:label="lab_opi_A11020SunCenterDriveRanchoCordovaCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">11020 Sun Center Drive, Rancho Cordova, CA</link:label>
    <link:label id="lab_opi_A11020SunCenterDriveRanchoCordovaCAMember_label_en-US" xlink:label="lab_opi_A11020SunCenterDriveRanchoCordovaCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">11020 Sun Center Drive, Rancho Cordova, CA [Member]</link:label>
    <link:label id="lab_opi_A11020SunCenterDriveRanchoCordovaCAMember_documentation_en-US" xlink:label="lab_opi_A11020SunCenterDriveRanchoCordovaCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">11020 Sun Center Drive, Rancho Cordova, CA [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A11020SunCenterDriveRanchoCordovaCAMember" xlink:href="opi-20251231.xsd#opi_A11020SunCenterDriveRanchoCordovaCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A11020SunCenterDriveRanchoCordovaCAMember" xlink:to="lab_opi_A11020SunCenterDriveRanchoCordovaCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_019dbc7a-b287-76a7-90d7-1742fd210e42_terseLabel_en-US" xlink:label="lab_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate, Type of Property [Axis]</link:label>
    <link:label id="lab_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_label_en-US" xlink:label="lab_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate, Type of Property [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" xlink:to="lab_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_GainLossOnExtinguishmentOfDebtNet_019dbc7a-b287-7a54-8e58-f74ebdc6acee_terseLabel_en-US" xlink:label="lab_opi_GainLossOnExtinguishmentOfDebtNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">(Loss) gain on early extinguishment of debt</link:label>
    <link:label id="lab_opi_GainLossOnExtinguishmentOfDebtNet_label_en-US" xlink:label="lab_opi_GainLossOnExtinguishmentOfDebtNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gain (Loss) On Extinguishment Of Debt, Net</link:label>
    <link:label id="lab_opi_GainLossOnExtinguishmentOfDebtNet_documentation_en-US" xlink:label="lab_opi_GainLossOnExtinguishmentOfDebtNet" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gain (Loss) On Extinguishment Of Debt, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_GainLossOnExtinguishmentOfDebtNet" xlink:href="opi-20251231.xsd#opi_GainLossOnExtinguishmentOfDebtNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_GainLossOnExtinguishmentOfDebtNet" xlink:to="lab_opi_GainLossOnExtinguishmentOfDebtNet" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A1000W.FultonChicagoILMember_019dbc7a-b1cb-74e7-80fd-6fe7ac28ad13_terseLabel_en-US" xlink:label="lab_opi_A1000W.FultonChicagoILMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">1000 W. Fulton, Chicago, IL</link:label>
    <link:label id="lab_opi_A1000W.FultonChicagoILMember_label_en-US" xlink:label="lab_opi_A1000W.FultonChicagoILMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">1000 W. Fulton, Chicago, IL [Member]</link:label>
    <link:label id="lab_opi_A1000W.FultonChicagoILMember_documentation_en-US" xlink:label="lab_opi_A1000W.FultonChicagoILMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">1000 W. Fulton, Chicago, IL</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A1000W.FultonChicagoILMember" xlink:href="opi-20251231.xsd#opi_A1000W.FultonChicagoILMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A1000W.FultonChicagoILMember" xlink:to="lab_opi_A1000W.FultonChicagoILMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtConversionLineItems_019dbc7a-b287-786c-be5e-214911d91c10_terseLabel_en-US" xlink:label="lab_us-gaap_DebtConversionLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Conversion [Line Items]</link:label>
    <link:label id="lab_us-gaap_DebtConversionLineItems_label_en-US" xlink:label="lab_us-gaap_DebtConversionLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Conversion [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtConversionLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtConversionLineItems" xlink:to="lab_us-gaap_DebtConversionLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_TenantImprovements_019dbc7a-b287-7c0c-91e3-ba8a184a390a_terseLabel_en-US" xlink:label="lab_us-gaap_TenantImprovements" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tenant improvements</link:label>
    <link:label id="lab_us-gaap_TenantImprovements_label_en-US" xlink:label="lab_us-gaap_TenantImprovements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tenant Improvements</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TenantImprovements" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TenantImprovements"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TenantImprovements" xlink:to="lab_us-gaap_TenantImprovements" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LeaseIncome_019dbc7a-b286-75e1-9dcb-230f98d5ddab_terseLabel_en-US" xlink:label="lab_us-gaap_LeaseIncome" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rental income</link:label>
    <link:label id="lab_us-gaap_LeaseIncome_label_en-US" xlink:label="lab_us-gaap_LeaseIncome" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lease Income</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseIncome" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LeaseIncome"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LeaseIncome" xlink:to="lab_us-gaap_LeaseIncome" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSix_019dbc7a-b286-709e-9922-0e637d4f77a2_terseLabel_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSix" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2031</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSix_label_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSix" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right Exercisable In Year Six</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSix_documentation_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSix" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the percentage as a concentration risk for termination right exercisable in year six from the balance sheet date.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSix" xlink:href="opi-20251231.xsd#opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSix"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSix" xlink:to="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSix" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccumulatedAmortizationDeferredFinanceCosts_019dbc7a-b1cb-76bf-8079-82205cef4490_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedAmortizationDeferredFinanceCosts" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accumulated amortization of deferred financing fees</link:label>
    <link:label id="lab_us-gaap_AccumulatedAmortizationDeferredFinanceCosts_label_en-US" xlink:label="lab_us-gaap_AccumulatedAmortizationDeferredFinanceCosts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accumulated Amortization, Debt Issuance Costs</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedAmortizationDeferredFinanceCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedAmortizationDeferredFinanceCosts"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedAmortizationDeferredFinanceCosts" xlink:to="lab_us-gaap_AccumulatedAmortizationDeferredFinanceCosts" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears_019dbc7a-b286-7d63-87ae-b7eb1af71519_terseLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2027</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received, Year Two</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears" xlink:to="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CapitalExpendituresIncurredButNotYetPaid_019dbc8e-422e-76b4-9199-09461d2b0faa_terseLabel_en-US" xlink:label="lab_us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real estate improvements accrued, not paid</link:label>
    <link:label id="lab_us-gaap_CapitalExpendituresIncurredButNotYetPaid_label_en-US" xlink:label="lab_us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capital Expenditures Incurred but Not yet Paid</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CapitalExpendituresIncurredButNotYetPaid"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:to="lab_us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019dbc7a-b286-78f3-ba4a-5eda2f96c21b_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Maximum borrowing capacity on revolving credit facility</link:label>
    <link:label id="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_label_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Line of Credit Facility, Maximum Borrowing Capacity</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:to="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockRepurchasedDuringPeriodShares_019dbc7a-b1cb-793e-b043-c0984c805032_terseLabel_en-US" xlink:label="lab_us-gaap_StockRepurchasedDuringPeriodShares" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share repurchases (in shares)</link:label>
    <link:label id="lab_us-gaap_StockRepurchasedDuringPeriodShares_label_en-US" xlink:label="lab_us-gaap_StockRepurchasedDuringPeriodShares" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Repurchased During Period, Shares</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockRepurchasedDuringPeriodShares"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockRepurchasedDuringPeriodShares" xlink:to="lab_us-gaap_StockRepurchasedDuringPeriodShares" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtConversionOriginalDebtAmount1_019dbc7a-b1cb-7592-b0a8-fc72c234c437_terseLabel_en-US" xlink:label="lab_us-gaap_DebtConversionOriginalDebtAmount1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate Principal Amount of Existing Notes Accepted for Exchange</link:label>
    <link:label id="lab_us-gaap_DebtConversionOriginalDebtAmount1_label_en-US" xlink:label="lab_us-gaap_DebtConversionOriginalDebtAmount1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Conversion, Original Debt, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionOriginalDebtAmount1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtConversionOriginalDebtAmount1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtConversionOriginalDebtAmount1" xlink:to="lab_us-gaap_DebtConversionOriginalDebtAmount1" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtConversionTable_019dbc7a-b1cb-7d59-96c6-92c78902b548_terseLabel_en-US" xlink:label="lab_us-gaap_DebtConversionTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Conversion [Table]</link:label>
    <link:label id="lab_us-gaap_DebtConversionTable_label_en-US" xlink:label="lab_us-gaap_DebtConversionTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Conversion [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtConversionTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtConversionTable" xlink:to="lab_us-gaap_DebtConversionTable" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_MaldenMAMember_019dbc7a-b1cb-73e0-8c97-72ebdca1dfed_terseLabel_en-US" xlink:label="lab_opi_MaldenMAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Malden, MA</link:label>
    <link:label id="lab_opi_MaldenMAMember_label_en-US" xlink:label="lab_opi_MaldenMAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Malden, MA [Member]</link:label>
    <link:label id="lab_opi_MaldenMAMember_documentation_en-US" xlink:label="lab_opi_MaldenMAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Malden, MA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_MaldenMAMember" xlink:href="opi-20251231.xsd#opi_MaldenMAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_MaldenMAMember" xlink:to="lab_opi_MaldenMAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_BusinessAndPropertyManagementAgreementsTextBlock_019dbc7a-b286-7d34-b105-ce3d4a543d35_terseLabel_en-US" xlink:label="lab_opi_BusinessAndPropertyManagementAgreementsTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Business and Property Management Agreements with RMR</link:label>
    <link:label id="lab_opi_BusinessAndPropertyManagementAgreementsTextBlock_label_en-US" xlink:label="lab_opi_BusinessAndPropertyManagementAgreementsTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business And Property Management Agreements [Text Block]</link:label>
    <link:label id="lab_opi_BusinessAndPropertyManagementAgreementsTextBlock_documentation_en-US" xlink:label="lab_opi_BusinessAndPropertyManagementAgreementsTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Business and Property Management Agreements [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_BusinessAndPropertyManagementAgreementsTextBlock" xlink:href="opi-20251231.xsd#opi_BusinessAndPropertyManagementAgreementsTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_BusinessAndPropertyManagementAgreementsTextBlock" xlink:to="lab_opi_BusinessAndPropertyManagementAgreementsTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_AcquiredBelowMarketLeaseAmortizationPeriod_019dbc7a-b286-7fd9-b350-bffcb3599a2b_terseLabel_en-US" xlink:label="lab_opi_AcquiredBelowMarketLeaseAmortizationPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Below market, acquired lease amortization period</link:label>
    <link:label id="lab_opi_AcquiredBelowMarketLeaseAmortizationPeriod_label_en-US" xlink:label="lab_opi_AcquiredBelowMarketLeaseAmortizationPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Acquired Below Market Lease Amortization Period</link:label>
    <link:label id="lab_opi_AcquiredBelowMarketLeaseAmortizationPeriod_documentation_en-US" xlink:label="lab_opi_AcquiredBelowMarketLeaseAmortizationPeriod" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amortization period for leases with a finite life acquired as part of a real property acquisition at below market lease rate.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_AcquiredBelowMarketLeaseAmortizationPeriod" xlink:href="opi-20251231.xsd#opi_AcquiredBelowMarketLeaseAmortizationPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_AcquiredBelowMarketLeaseAmortizationPeriod" xlink:to="lab_opi_AcquiredBelowMarketLeaseAmortizationPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearOne_019dbc7a-b1cb-754f-99cb-399c80c009a9_terseLabel_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearOne" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2026</link:label>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearOne_label_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearOne" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Costs, Leasing Future Amortization Expense Year One</link:label>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearOne_documentation_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearOne" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of amortization of deferred leasing costs expected to be recognized during year one of the five succeeding fiscal years.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DeferredCostsLeasingFutureAmortizationExpenseYearOne" xlink:href="opi-20251231.xsd#opi_DeferredCostsLeasingFutureAmortizationExpenseYearOne"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DeferredCostsLeasingFutureAmortizationExpenseYearOne" xlink:to="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearOne" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation_019dbc81-95ca-74dd-8d4d-374d448b0723_terseLabel_en-US" xlink:label="lab_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common share grants</link:label>
    <link:label id="lab_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation_label_en-US" xlink:label="lab_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Shares Granted, Value, Share-Based Payment Arrangement, after Forfeiture</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation" xlink:to="lab_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementLineItems_019dbc7a-b286-78aa-8cbd-edee4e6faf73_terseLabel_en-US" xlink:label="lab_us-gaap_StatementLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statement [Line Items]</link:label>
    <link:label id="lab_us-gaap_StatementLineItems_label_en-US" xlink:label="lab_us-gaap_StatementLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementLineItems" xlink:to="lab_us-gaap_StatementLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ExtinguishmentOfDebtAmount_019dbc7a-b287-74f2-8751-af403a906948_terseLabel_en-US" xlink:label="lab_us-gaap_ExtinguishmentOfDebtAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt redeemed</link:label>
    <link:label id="lab_us-gaap_ExtinguishmentOfDebtAmount_label_en-US" xlink:label="lab_us-gaap_ExtinguishmentOfDebtAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Extinguishment of Debt, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExtinguishmentOfDebtAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ExtinguishmentOfDebtAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ExtinguishmentOfDebtAmount" xlink:to="lab_us-gaap_ExtinguishmentOfDebtAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_Rule10b51ArrAdoptedFlag_terseLabel_en-US" xlink:label="lab_ecd_Rule10b51ArrAdoptedFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rule 10b5-1 Arrangement Adopted</link:label>
    <link:label id="lab_ecd_Rule10b51ArrAdoptedFlag_label_en-US" xlink:label="lab_ecd_Rule10b51ArrAdoptedFlag" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Rule 10b5-1 Arrangement Adopted [Flag]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_Rule10b51ArrAdoptedFlag" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_Rule10b51ArrAdoptedFlag"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_Rule10b51ArrAdoptedFlag" xlink:to="lab_ecd_Rule10b51ArrAdoptedFlag" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_019dbc7a-b287-7b42-b885-a15999520b86_terseLabel_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash and cash equivalents</link:label>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_label_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash and Cash Equivalent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:to="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockMember_019dbc7a-b30c-72b0-9d24-dd0ab2d6f509_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common Shares</link:label>
    <link:label id="lab_us-gaap_CommonStockMember_label_en-US" xlink:label="lab_us-gaap_CommonStockMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockMember" xlink:to="lab_us-gaap_CommonStockMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_019dbc7a-b1cb-7263-9d02-da8ddb782a92_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Vested (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation_019dbc7a-b287-7e43-885e-00c04e4b1edb_negatedLabel_en-US" xlink:label="lab_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Accumulated depreciation</link:label>
    <link:label id="lab_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation_label_en-US" xlink:label="lab_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Investment Property, Accumulated Depreciation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation" xlink:to="lab_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019dbc8d-e67e-7161-ae38-602e67a8ba33_totalLabel_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">(Decrease) increase in cash, cash equivalents and restricted cash</link:label>
    <link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_label_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockDividendsPerShareCashPaid_019dbc7a-b1cb-7713-bc6b-803a6b7ec735_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockDividendsPerShareCashPaid" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Annual Per Share Distribution (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_CommonStockDividendsPerShareCashPaid_label_en-US" xlink:label="lab_us-gaap_CommonStockDividendsPerShareCashPaid" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock, Dividends, Per Share, Cash Paid</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockDividendsPerShareCashPaid" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockDividendsPerShareCashPaid"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockDividendsPerShareCashPaid" xlink:to="lab_us-gaap_CommonStockDividendsPerShareCashPaid" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearTwo_019dbc7a-b287-7f34-b13b-23009c7ed80c_terseLabel_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2027</link:label>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearTwo_label_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Costs, Leasing Future Amortization Expense Year Two</link:label>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearTwo_documentation_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearTwo" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of amortization of deferred leasing costs expected to be recognized during year two of the five succeeding fiscal years.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DeferredCostsLeasingFutureAmortizationExpenseYearTwo" xlink:href="opi-20251231.xsd#opi_DeferredCostsLeasingFutureAmortizationExpenseYearTwo"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DeferredCostsLeasingFutureAmortizationExpenseYearTwo" xlink:to="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearTwo" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SignificantAccountingPoliciesTextBlock_019dbc7a-b286-748b-9700-42ec7302a1f2_terseLabel_en-US" xlink:label="lab_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Summary of Significant Accounting Policies</link:label>
    <link:label id="lab_us-gaap_SignificantAccountingPoliciesTextBlock_label_en-US" xlink:label="lab_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Significant Accounting Policies [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SignificantAccountingPoliciesTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:to="lab_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RangeMember_019dbc7a-b286-73e8-9904-17009f4be4da_terseLabel_en-US" xlink:label="lab_srt_RangeMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statistical Measurement [Domain]</link:label>
    <link:label id="lab_srt_RangeMember_label_en-US" xlink:label="lab_srt_RangeMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statistical Measurement [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RangeMember" xlink:to="lab_srt_RangeMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A20MassachusettsAvenueWashingtonDCMember_019dbc7a-b1cb-7da6-b22c-d6fd7d74824d_terseLabel_en-US" xlink:label="lab_opi_A20MassachusettsAvenueWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">20 Massachusetts Avenue, Washington DC</link:label>
    <link:label id="lab_opi_A20MassachusettsAvenueWashingtonDCMember_label_en-US" xlink:label="lab_opi_A20MassachusettsAvenueWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">20 Massachusetts Avenue, Washington, DC [Member]</link:label>
    <link:label id="lab_opi_A20MassachusettsAvenueWashingtonDCMember_documentation_en-US" xlink:label="lab_opi_A20MassachusettsAvenueWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">20 Massachusetts Avenue, Washington, DC</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A20MassachusettsAvenueWashingtonDCMember" xlink:href="opi-20251231.xsd#opi_A20MassachusettsAvenueWashingtonDCMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A20MassachusettsAvenueWashingtonDCMember" xlink:to="lab_opi_A20MassachusettsAvenueWashingtonDCMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RelatedPartyTransactionAxis_019dbc7a-b1cb-79e8-90b2-dca1c9163433_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Related Party Transaction [Axis]</link:label>
    <link:label id="lab_us-gaap_RelatedPartyTransactionAxis_label_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis" xlink:to="lab_us-gaap_RelatedPartyTransactionAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_019dbc7a-b287-76e6-8a64-454ab72b8e5f_terseLabel_en-US" xlink:label="lab_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate [Domain]</link:label>
    <link:label id="lab_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_label_en-US" xlink:label="lab_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MortgageLoansOnRealEstateNamePropertyTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain" xlink:to="lab_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SonestaManagementAgreementPeriodOneMember_019dbc7a-b1cb-7169-888a-8fa181d9d0a1_terseLabel_en-US" xlink:label="lab_opi_SonestaManagementAgreementPeriodOneMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sonesta Management Agreement, Period One</link:label>
    <link:label id="lab_opi_SonestaManagementAgreementPeriodOneMember_label_en-US" xlink:label="lab_opi_SonestaManagementAgreementPeriodOneMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sonesta Management Agreement, Period One [Member]</link:label>
    <link:label id="lab_opi_SonestaManagementAgreementPeriodOneMember_documentation_en-US" xlink:label="lab_opi_SonestaManagementAgreementPeriodOneMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sonesta Management Agreement, Period One</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SonestaManagementAgreementPeriodOneMember" xlink:href="opi-20251231.xsd#opi_SonestaManagementAgreementPeriodOneMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SonestaManagementAgreementPeriodOneMember" xlink:to="lab_opi_SonestaManagementAgreementPeriodOneMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInLeasingReceivables_019dbc87-c81b-7053-bd83-b4822ce708fe_negatedLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInLeasingReceivables" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Rents receivable</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInLeasingReceivables_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInLeasingReceivables" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Leasing Receivables</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInLeasingReceivables" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInLeasingReceivables"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInLeasingReceivables" xlink:to="lab_us-gaap_IncreaseDecreaseInLeasingReceivables" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeLossFromEquityMethodInvestments_019dbc7a-b287-794b-b34d-ad3c4c2bf8d6_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromEquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity in net losses of investees</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromEquityMethodInvestments_019dbc87-2c93-7661-a2ae-3ba9564465df_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromEquityMethodInvestments" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Equity in net losses of investees</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromEquityMethodInvestments_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromEquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Equity Method Investments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromEquityMethodInvestments" xlink:to="lab_us-gaap_IncomeLossFromEquityMethodInvestments" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LeasesAbstract_label_en-US" xlink:label="lab_us-gaap_LeasesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Leases [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LeasesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LeasesAbstract" xlink:to="lab_us-gaap_LeasesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears_019dbc7a-b1cb-78bb-b209-4b1a2c51425f_terseLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2029</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received, Year Four</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears" xlink:to="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DividendsDeclaredTableTextBlock_019dbc7a-b286-7646-98c7-3fccdaec4611_terseLabel_en-US" xlink:label="lab_us-gaap_DividendsDeclaredTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Dividends</link:label>
    <link:label id="lab_us-gaap_DividendsDeclaredTableTextBlock_label_en-US" xlink:label="lab_us-gaap_DividendsDeclaredTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dividends Declared [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsDeclaredTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DividendsDeclaredTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DividendsDeclaredTableTextBlock" xlink:to="lab_us-gaap_DividendsDeclaredTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A180TedTurnerDriveSWAtlantaGAMember_019dbc7a-b1cb-7653-a44f-2df0ce4173fd_terseLabel_en-US" xlink:label="lab_opi_A180TedTurnerDriveSWAtlantaGAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">180 Ted Turner Drive SW, Atlanta, GA</link:label>
    <link:label id="lab_opi_A180TedTurnerDriveSWAtlantaGAMember_label_en-US" xlink:label="lab_opi_A180TedTurnerDriveSWAtlantaGAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">180 Ted Turner Drive SW, Atlanta, GA [Member]</link:label>
    <link:label id="lab_opi_A180TedTurnerDriveSWAtlantaGAMember_documentation_en-US" xlink:label="lab_opi_A180TedTurnerDriveSWAtlantaGAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">180 Ted Turner Drive SW, Atlanta, GA [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A180TedTurnerDriveSWAtlantaGAMember" xlink:href="opi-20251231.xsd#opi_A180TedTurnerDriveSWAtlantaGAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A180TedTurnerDriveSWAtlantaGAMember" xlink:to="lab_opi_A180TedTurnerDriveSWAtlantaGAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementOperatingActivitiesSegmentAxis_019dbc7a-b1cb-7646-8368-55b6045ec340_terseLabel_en-US" xlink:label="lab_us-gaap_StatementOperatingActivitiesSegmentAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating Activities [Axis]</link:label>
    <link:label id="lab_us-gaap_StatementOperatingActivitiesSegmentAxis_label_en-US" xlink:label="lab_us-gaap_StatementOperatingActivitiesSegmentAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Activities [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOperatingActivitiesSegmentAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementOperatingActivitiesSegmentAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOperatingActivitiesSegmentAxis" xlink:to="lab_us-gaap_StatementOperatingActivitiesSegmentAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand_019dbc7a-b287-7f46-a813-0234e437b85b_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Land</link:label>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand_label_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Land, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand" xlink:to="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock_019dbc7a-b287-7cef-92a6-13d4e50f2736_verboseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Disposal Groups</link:label>
    <link:label id="lab_us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Groups, Including Discontinued Operations [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock" xlink:to="lab_us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LiabilitiesNotSubjectToCompromise_019dbc7a-b287-7e80-935a-84de0a770edc_totalLabel_en-US" xlink:label="lab_opi_LiabilitiesNotSubjectToCompromise" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total liabilities not subject to compromise</link:label>
    <link:label id="lab_opi_LiabilitiesNotSubjectToCompromise_label_en-US" xlink:label="lab_opi_LiabilitiesNotSubjectToCompromise" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities Not Subject To Compromise</link:label>
    <link:label id="lab_opi_LiabilitiesNotSubjectToCompromise_documentation_en-US" xlink:label="lab_opi_LiabilitiesNotSubjectToCompromise" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Liabilities Not Subject To Compromise</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LiabilitiesNotSubjectToCompromise" xlink:href="opi-20251231.xsd#opi_LiabilitiesNotSubjectToCompromise"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LiabilitiesNotSubjectToCompromise" xlink:to="lab_opi_LiabilitiesNotSubjectToCompromise" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherReceivableAfterAllowanceForCreditLossNoncurrent_019dd0e2-fbb3-7701-ac1a-7734d6aca698_terseLabel_en-US" xlink:label="lab_us-gaap_OtherReceivableAfterAllowanceForCreditLossNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Intercompany due from non-debtor entities</link:label>
    <link:label id="lab_us-gaap_OtherReceivableAfterAllowanceForCreditLossNoncurrent_label_en-US" xlink:label="lab_us-gaap_OtherReceivableAfterAllowanceForCreditLossNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Receivable, after Allowance for Credit Loss, Noncurrent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherReceivableAfterAllowanceForCreditLossNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherReceivableAfterAllowanceForCreditLossNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherReceivableAfterAllowanceForCreditLossNoncurrent" xlink:to="lab_us-gaap_OtherReceivableAfterAllowanceForCreditLossNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_TradingArrByIndTable_terseLabel_en-US" xlink:label="lab_ecd_TradingArrByIndTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Trading Arrangements, by Individual</link:label>
    <link:label id="lab_ecd_TradingArrByIndTable_label_en-US" xlink:label="lab_ecd_TradingArrByIndTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Trading Arrangements, by Individual [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_TradingArrByIndTable" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_TradingArrByIndTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_TradingArrByIndTable" xlink:to="lab_ecd_TradingArrByIndTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EarningsPerShareBasic_019dbc7a-b287-70a9-a93c-1e39ddf2fc59_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareBasic" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net loss (basic) (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_EarningsPerShareBasic_019dbc7a-b287-7941-acd1-f47569f44884_verboseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareBasic" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Net loss per common share - basic (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_EarningsPerShareBasic_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareBasic" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Earnings Per Share, Basic</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareBasic" xlink:to="lab_us-gaap_EarningsPerShareBasic" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_019dbc87-db6f-746e-9311-374ed0c12660_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts payable and other liabilities</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Accounts Payable and Accrued Liabilities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:to="lab_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A12795WestAlamedaParkwayLakewoodCOMember_019dbc7a-b1cb-7af7-bf74-92c6b878cd31_terseLabel_en-US" xlink:label="lab_opi_A12795WestAlamedaParkwayLakewoodCOMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">12795 West Alameda Parkway, Lakewood, CO</link:label>
    <link:label id="lab_opi_A12795WestAlamedaParkwayLakewoodCOMember_label_en-US" xlink:label="lab_opi_A12795WestAlamedaParkwayLakewoodCOMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">12795 West Alameda Parkway, Lakewood, CO [Member]</link:label>
    <link:label id="lab_opi_A12795WestAlamedaParkwayLakewoodCOMember_documentation_en-US" xlink:label="lab_opi_A12795WestAlamedaParkwayLakewoodCOMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">12795 West Alameda Parkway, Lakewood, CO</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A12795WestAlamedaParkwayLakewoodCOMember" xlink:href="opi-20251231.xsd#opi_A12795WestAlamedaParkwayLakewoodCOMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A12795WestAlamedaParkwayLakewoodCOMember" xlink:to="lab_opi_A12795WestAlamedaParkwayLakewoodCOMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A7671MortgageNotesPayableMember_019dbcab-7c47-7ca7-ab73-bcf652eabf8e_terseLabel_en-US" xlink:label="lab_opi_A7671MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mortgage note payable, 7.671% interest rate, due in 2028</link:label>
    <link:label id="lab_opi_A7671MortgageNotesPayableMember_label_en-US" xlink:label="lab_opi_A7671MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">7.671% Mortgage Notes Payable [Member]</link:label>
    <link:label id="lab_opi_A7671MortgageNotesPayableMember_documentation_en-US" xlink:label="lab_opi_A7671MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">7.671% Mortgage Notes Payable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A7671MortgageNotesPayableMember" xlink:href="opi-20251231.xsd#opi_A7671MortgageNotesPayableMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A7671MortgageNotesPayableMember" xlink:to="lab_opi_A7671MortgageNotesPayableMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_AtlanticCorporateParkSterlingVAMember_019dbc7a-b1cb-7e0f-bcab-bab8c732304c_terseLabel_en-US" xlink:label="lab_opi_AtlanticCorporateParkSterlingVAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Atlantic Corporate Park, Sterling, VA</link:label>
    <link:label id="lab_opi_AtlanticCorporateParkSterlingVAMember_label_en-US" xlink:label="lab_opi_AtlanticCorporateParkSterlingVAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlantic Corporate Park, Sterling, VA [Member]</link:label>
    <link:label id="lab_opi_AtlanticCorporateParkSterlingVAMember_documentation_en-US" xlink:label="lab_opi_AtlanticCorporateParkSterlingVAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlantic Corporate Park [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_AtlanticCorporateParkSterlingVAMember" xlink:href="opi-20251231.xsd#opi_AtlanticCorporateParkSterlingVAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_AtlanticCorporateParkSterlingVAMember" xlink:to="lab_opi_AtlanticCorporateParkSterlingVAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A1751BlueHillsDriveRoanokeVAMember_019dbc7a-b287-7f07-9190-74f2280b4ccf_terseLabel_en-US" xlink:label="lab_opi_A1751BlueHillsDriveRoanokeVAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">1751 Blue Hills Drive, Roanoke, VA</link:label>
    <link:label id="lab_opi_A1751BlueHillsDriveRoanokeVAMember_label_en-US" xlink:label="lab_opi_A1751BlueHillsDriveRoanokeVAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">1751 Blue Hills Drive, Roanoke, VA [Member]</link:label>
    <link:label id="lab_opi_A1751BlueHillsDriveRoanokeVAMember_documentation_en-US" xlink:label="lab_opi_A1751BlueHillsDriveRoanokeVAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">1751 Blue Hills Drive, Roanoke, VA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A1751BlueHillsDriveRoanokeVAMember" xlink:href="opi-20251231.xsd#opi_A1751BlueHillsDriveRoanokeVAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A1751BlueHillsDriveRoanokeVAMember" xlink:to="lab_opi_A1751BlueHillsDriveRoanokeVAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseAbstract_019dbc7a-b1cb-7e7a-bf01-4af8dddd4139_verboseLabel_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseAbstract" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Future amortization of deferred leasing costs, excluding those classified as discontinued operations</link:label>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseAbstract_label_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Costs, Leasing Future Amortization Expense [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DeferredCostsLeasingFutureAmortizationExpenseAbstract" xlink:href="opi-20251231.xsd#opi_DeferredCostsLeasingFutureAmortizationExpenseAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DeferredCostsLeasingFutureAmortizationExpenseAbstract" xlink:to="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A10949N.MatherBoulevardRanchoCordovaCAMember_019dbc7a-b1cb-7b09-bab9-2f7a2952b127_terseLabel_en-US" xlink:label="lab_opi_A10949N.MatherBoulevardRanchoCordovaCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">10949 N. Mather Boulevard, Rancho Cordova, CA</link:label>
    <link:label id="lab_opi_A10949N.MatherBoulevardRanchoCordovaCAMember_label_en-US" xlink:label="lab_opi_A10949N.MatherBoulevardRanchoCordovaCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">10949 N. Mather Boulevard, Rancho Cordova, CA [Member]</link:label>
    <link:label id="lab_opi_A10949N.MatherBoulevardRanchoCordovaCAMember_documentation_en-US" xlink:label="lab_opi_A10949N.MatherBoulevardRanchoCordovaCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">10949 N. Mather Boulevard, Rancho Cordova, CA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A10949N.MatherBoulevardRanchoCordovaCAMember" xlink:href="opi-20251231.xsd#opi_A10949N.MatherBoulevardRanchoCordovaCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A10949N.MatherBoulevardRanchoCordovaCAMember" xlink:to="lab_opi_A10949N.MatherBoulevardRanchoCordovaCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SantaClaraCAMember_019dbc7a-b1cb-72c6-b9c7-76bc7e1ad997_terseLabel_en-US" xlink:label="lab_opi_SantaClaraCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Santa Clara, CA</link:label>
    <link:label id="lab_opi_SantaClaraCAMember_label_en-US" xlink:label="lab_opi_SantaClaraCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Santa Clara, CA [Member]</link:label>
    <link:label id="lab_opi_SantaClaraCAMember_documentation_en-US" xlink:label="lab_opi_SantaClaraCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Santa Clara, CA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SantaClaraCAMember" xlink:href="opi-20251231.xsd#opi_SantaClaraCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SantaClaraCAMember" xlink:to="lab_opi_SantaClaraCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AwardTmgMnpiDiscTextBlock_terseLabel_en-US" xlink:label="lab_ecd_AwardTmgMnpiDiscTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Award Timing MNPI Disclosure</link:label>
    <link:label id="lab_ecd_AwardTmgMnpiDiscTextBlock_label_en-US" xlink:label="lab_ecd_AwardTmgMnpiDiscTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Award Timing MNPI Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AwardTmgMnpiDiscTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AwardTmgMnpiDiscTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AwardTmgMnpiDiscTextBlock" xlink:to="lab_ecd_AwardTmgMnpiDiscTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BelowMarketLeaseAccumulatedAmortization_019dbc7a-b1cb-7f2b-ac9b-002f285581d9_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_BelowMarketLeaseAccumulatedAmortization" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Less: accumulated amortization</link:label>
    <link:label id="lab_us-gaap_BelowMarketLeaseAccumulatedAmortization_label_en-US" xlink:label="lab_us-gaap_BelowMarketLeaseAccumulatedAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Below Market Lease, Accumulated Amortization</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseAccumulatedAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BelowMarketLeaseAccumulatedAmortization"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BelowMarketLeaseAccumulatedAmortization" xlink:to="lab_us-gaap_BelowMarketLeaseAccumulatedAmortization" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A11DupontCircleNWWashingtonDCMember_019dbc7a-b1cb-7fc4-8c80-e1f497a6ec8d_terseLabel_en-US" xlink:label="lab_opi_A11DupontCircleNWWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">11 Dupont Circle, NW, Washington DC</link:label>
    <link:label id="lab_opi_A11DupontCircleNWWashingtonDCMember_label_en-US" xlink:label="lab_opi_A11DupontCircleNWWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">11 Dupont Circle, NW, Washington DC [Member]</link:label>
    <link:label id="lab_opi_A11DupontCircleNWWashingtonDCMember_documentation_en-US" xlink:label="lab_opi_A11DupontCircleNWWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">11 Dupont Circle, NW, Washington DC [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A11DupontCircleNWWashingtonDCMember" xlink:href="opi-20251231.xsd#opi_A11DupontCircleNWWashingtonDCMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A11DupontCircleNWWashingtonDCMember" xlink:to="lab_opi_A11DupontCircleNWWashingtonDCMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LongTermDebtReorganizedCommonStockPercentDiscountOnPlanEquityValue_019dd0ae-50e1-763c-a697-c327251f8466_terseLabel_en-US" xlink:label="lab_opi_LongTermDebtReorganizedCommonStockPercentDiscountOnPlanEquityValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Plan equity value discount percentage</link:label>
    <link:label id="lab_opi_LongTermDebtReorganizedCommonStockPercentDiscountOnPlanEquityValue_label_en-US" xlink:label="lab_opi_LongTermDebtReorganizedCommonStockPercentDiscountOnPlanEquityValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Reorganized Common Stock, Percent Discount On Plan Equity Value</link:label>
    <link:label id="lab_opi_LongTermDebtReorganizedCommonStockPercentDiscountOnPlanEquityValue_documentation_en-US" xlink:label="lab_opi_LongTermDebtReorganizedCommonStockPercentDiscountOnPlanEquityValue" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Equity Rights Offering And Reorganized Common Stock Proceeds, Percent Discount On Chapter 11 Plan Equity Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LongTermDebtReorganizedCommonStockPercentDiscountOnPlanEquityValue" xlink:href="opi-20251231.xsd#opi_LongTermDebtReorganizedCommonStockPercentDiscountOnPlanEquityValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LongTermDebtReorganizedCommonStockPercentDiscountOnPlanEquityValue" xlink:to="lab_opi_LongTermDebtReorganizedCommonStockPercentDiscountOnPlanEquityValue" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ProvoUTMember_019dbc7a-b287-7210-ac1b-99ff54813914_terseLabel_en-US" xlink:label="lab_opi_ProvoUTMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Provo, UT</link:label>
    <link:label id="lab_opi_ProvoUTMember_label_en-US" xlink:label="lab_opi_ProvoUTMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Provo, UT [Member]</link:label>
    <link:label id="lab_opi_ProvoUTMember_documentation_en-US" xlink:label="lab_opi_ProvoUTMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Provo, UT</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ProvoUTMember" xlink:href="opi-20251231.xsd#opi_ProvoUTMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ProvoUTMember" xlink:to="lab_opi_ProvoUTMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_TenantReimbursementIncome_019dbc7a-b286-79db-83bd-283c7a326160_terseLabel_en-US" xlink:label="lab_opi_TenantReimbursementIncome" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tenant reimbursement income</link:label>
    <link:label id="lab_opi_TenantReimbursementIncome_label_en-US" xlink:label="lab_opi_TenantReimbursementIncome" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tenant Reimbursement Income</link:label>
    <link:label id="lab_opi_TenantReimbursementIncome_documentation_en-US" xlink:label="lab_opi_TenantReimbursementIncome" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tenant Reimbursement Income</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_TenantReimbursementIncome" xlink:href="opi-20251231.xsd#opi_TenantReimbursementIncome"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_TenantReimbursementIncome" xlink:to="lab_opi_TenantReimbursementIncome" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAccumulatedDepreciationReclassificationAssetsHeldForSale_019dbc7a-b287-734d-ac4f-80cce67917a0_negatedTerseLabel_en-US" xlink:label="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAccumulatedDepreciationReclassificationAssetsHeldForSale" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Reclassification of assets of properties held for sale</link:label>
    <link:label id="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAccumulatedDepreciationReclassificationAssetsHeldForSale_label_en-US" xlink:label="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAccumulatedDepreciationReclassificationAssetsHeldForSale" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment In Real Estate, Accumulated Depreciation, Reclassification Assets Held For Sale</link:label>
    <link:label id="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAccumulatedDepreciationReclassificationAssetsHeldForSale_documentation_en-US" xlink:label="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAccumulatedDepreciationReclassificationAssetsHeldForSale" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amount of deductions for reclassifications of assets held for sale to accumulated depreciation, excluding sales, for entities with a substantial portion of business acquiring and holding investment real estate.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAccumulatedDepreciationReclassificationAssetsHeldForSale" xlink:href="opi-20251231.xsd#opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAccumulatedDepreciationReclassificationAssetsHeldForSale"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAccumulatedDepreciationReclassificationAssetsHeldForSale" xlink:to="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateAccumulatedDepreciationReclassificationAssetsHeldForSale" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AllocatedShareBasedCompensationExpense_019dbc7a-b287-7aaa-9c80-74312b905e16_terseLabel_en-US" xlink:label="lab_us-gaap_AllocatedShareBasedCompensationExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Compensation expense</link:label>
    <link:label id="lab_us-gaap_AllocatedShareBasedCompensationExpense_label_en-US" xlink:label="lab_us-gaap_AllocatedShareBasedCompensationExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement, Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AllocatedShareBasedCompensationExpense" xlink:to="lab_us-gaap_AllocatedShareBasedCompensationExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsToDevelopRealEstateAssets_019dbc89-446a-782a-baca-9e7bd52f5a19_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToDevelopRealEstateAssets" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Real estate improvements</link:label>
    <link:label id="lab_us-gaap_PaymentsToDevelopRealEstateAssets_label_en-US" xlink:label="lab_us-gaap_PaymentsToDevelopRealEstateAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Develop Real Estate Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToDevelopRealEstateAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToDevelopRealEstateAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToDevelopRealEstateAssets" xlink:to="lab_us-gaap_PaymentsToDevelopRealEstateAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SecuredDebt_019dbc7a-b286-7d01-a926-29c8aaa6bbe7_terseLabel_en-US" xlink:label="lab_us-gaap_SecuredDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Secured debt, net</link:label>
    <link:label id="lab_us-gaap_SecuredDebt_019dbc7a-b286-79fe-b0d5-9985bdcb113d_verboseLabel_en-US" xlink:label="lab_us-gaap_SecuredDebt" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Mortgage notes payable</link:label>
    <link:label id="lab_us-gaap_SecuredDebt_label_en-US" xlink:label="lab_us-gaap_SecuredDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Secured Debt</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SecuredDebt" xlink:to="lab_us-gaap_SecuredDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquity_019dbc7a-b287-71f0-99a3-59a74017c6bc_totalLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total liabilities and shareholders&#8217; equity</link:label>
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquity_label_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities and Equity</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="lab_us-gaap_LiabilitiesAndStockholdersEquity" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtConversionOriginalDebtInterestRateOfDebt_019dbc7a-b286-713a-8521-3c9460965203_terseLabel_en-US" xlink:label="lab_us-gaap_DebtConversionOriginalDebtInterestRateOfDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Existing Notes Exchanged, Interest rate</link:label>
    <link:label id="lab_us-gaap_DebtConversionOriginalDebtInterestRateOfDebt_label_en-US" xlink:label="lab_us-gaap_DebtConversionOriginalDebtInterestRateOfDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Conversion, Original Debt, Interest Rate of Debt</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionOriginalDebtInterestRateOfDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtConversionOriginalDebtInterestRateOfDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtConversionOriginalDebtInterestRateOfDebt" xlink:to="lab_us-gaap_DebtConversionOriginalDebtInterestRateOfDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionNumberOfBusinessDayWindowAfterEndOfAnyCalendarYearPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForPerformanceByRelatedParty_019dbc7a-b1cb-769e-a174-3912de0d4cb6_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionNumberOfBusinessDayWindowAfterEndOfAnyCalendarYearPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForPerformanceByRelatedParty" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Window of written notice after calendar year</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionNumberOfBusinessDayWindowAfterEndOfAnyCalendarYearPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForPerformanceByRelatedParty_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionNumberOfBusinessDayWindowAfterEndOfAnyCalendarYearPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForPerformanceByRelatedParty" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction Number Of Business Day Window After End Of Any Calendar Year Prior Written Notice For Termination Of Property Management Agreement For Performance By Related Party</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionNumberOfBusinessDayWindowAfterEndOfAnyCalendarYearPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForPerformanceByRelatedParty_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionNumberOfBusinessDayWindowAfterEndOfAnyCalendarYearPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForPerformanceByRelatedParty" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the window or numbers of business days after any calendar year to provide notice for termination of property management agreement by the related party for performance reasons.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionNumberOfBusinessDayWindowAfterEndOfAnyCalendarYearPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForPerformanceByRelatedParty" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionNumberOfBusinessDayWindowAfterEndOfAnyCalendarYearPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForPerformanceByRelatedParty"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionNumberOfBusinessDayWindowAfterEndOfAnyCalendarYearPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForPerformanceByRelatedParty" xlink:to="lab_opi_RelatedPartyTransactionNumberOfBusinessDayWindowAfterEndOfAnyCalendarYearPriorWrittenNoticeForTerminationOfPropertyManagementAgreementForPerformanceByRelatedParty" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ConcentrationRiskByBenchmarkAxis_019dbc7a-b287-78f3-a5b6-8a6fe9a8d812_terseLabel_en-US" xlink:label="lab_us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Concentration Risk Benchmark [Axis]</link:label>
    <link:label id="lab_us-gaap_ConcentrationRiskByBenchmarkAxis_label_en-US" xlink:label="lab_us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Benchmark [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:to="lab_us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FreshStartAdjustmentsTable_019dd081-dfd7-7365-bc58-1d31fbbb20aa_terseLabel_en-US" xlink:label="lab_us-gaap_FreshStartAdjustmentsTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reorganization, Chapter 11 [Table]</link:label>
    <link:label id="lab_us-gaap_FreshStartAdjustmentsTable_label_en-US" xlink:label="lab_us-gaap_FreshStartAdjustmentsTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reorganization, Chapter 11 [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FreshStartAdjustmentsTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FreshStartAdjustmentsTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FreshStartAdjustmentsTable" xlink:to="lab_us-gaap_FreshStartAdjustmentsTable" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_JointVentureProperty1Member_019dbc7a-b1cb-733a-b06f-09d725fd8995_terseLabel_en-US" xlink:label="lab_opi_JointVentureProperty1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Joint Venture Property 1</link:label>
    <link:label id="lab_opi_JointVentureProperty1Member_label_en-US" xlink:label="lab_opi_JointVentureProperty1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Joint Venture Property 1 [Member]</link:label>
    <link:label id="lab_opi_JointVentureProperty1Member_documentation_en-US" xlink:label="lab_opi_JointVentureProperty1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Joint Venture Property 1 [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_JointVentureProperty1Member" xlink:href="opi-20251231.xsd#opi_JointVentureProperty1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_JointVentureProperty1Member" xlink:to="lab_opi_JointVentureProperty1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfEquityMethodInvestmentsTable_019dbc7a-b287-7f1e-ad55-5b988ef4b849_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity Method Investment [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfEquityMethodInvestmentsTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:to="lab_us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccountingPoliciesAbstract_019dbc7a-b1cb-7972-935d-c0e7cccbcffb_terseLabel_en-US" xlink:label="lab_us-gaap_AccountingPoliciesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounting Policies [Abstract]</link:label>
    <link:label id="lab_us-gaap_AccountingPoliciesAbstract_label_en-US" xlink:label="lab_us-gaap_AccountingPoliciesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounting Policies [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingPoliciesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountingPoliciesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountingPoliciesAbstract" xlink:to="lab_us-gaap_AccountingPoliciesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ConcentrationRiskTypeDomain_019dbc7a-b1cb-7f30-8c94-3a23a9c78ca7_terseLabel_en-US" xlink:label="lab_us-gaap_ConcentrationRiskTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Concentration Risk Type [Domain]</link:label>
    <link:label id="lab_us-gaap_ConcentrationRiskTypeDomain_label_en-US" xlink:label="lab_us-gaap_ConcentrationRiskTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Type [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain" xlink:to="lab_us-gaap_ConcentrationRiskTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RepaymentsOfSecuredDebt_019dbc8d-2bd0-766f-b6c4-8c399c79e9fe_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_RepaymentsOfSecuredDebt" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Repayment of senior secured notes</link:label>
    <link:label id="lab_us-gaap_RepaymentsOfSecuredDebt_019dbc7a-b287-793f-8270-31492b3d0e28_terseLabel_en-US" xlink:label="lab_us-gaap_RepaymentsOfSecuredDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Repayments of senior secured notes</link:label>
    <link:label id="lab_us-gaap_RepaymentsOfSecuredDebt_label_en-US" xlink:label="lab_us-gaap_RepaymentsOfSecuredDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Repayments of Secured Debt</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfSecuredDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RepaymentsOfSecuredDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RepaymentsOfSecuredDebt" xlink:to="lab_us-gaap_RepaymentsOfSecuredDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ExtinguishmentOfDebtGainLossPerShareNetOfTax_019dd0d3-7bfb-7948-85b9-c6aed1302963_terseLabel_en-US" xlink:label="lab_us-gaap_ExtinguishmentOfDebtGainLossPerShareNetOfTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gain on early extinguishment of debt per common share (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_ExtinguishmentOfDebtGainLossPerShareNetOfTax_label_en-US" xlink:label="lab_us-gaap_ExtinguishmentOfDebtGainLossPerShareNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Extinguishment of Debt, Gain (Loss), Per Share, Net of Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExtinguishmentOfDebtGainLossPerShareNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ExtinguishmentOfDebtGainLossPerShareNetOfTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ExtinguishmentOfDebtGainLossPerShareNetOfTax" xlink:to="lab_us-gaap_ExtinguishmentOfDebtGainLossPerShareNetOfTax" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_PayVsPerformanceDisclosureLineItems_label_en-US" xlink:label="lab_ecd_PayVsPerformanceDisclosureLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pay vs Performance Disclosure [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_PayVsPerformanceDisclosureLineItems" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_PayVsPerformanceDisclosureLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_PayVsPerformanceDisclosureLineItems" xlink:to="lab_ecd_PayVsPerformanceDisclosureLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceived_019dbc7a-b1cb-7b4c-8694-836cf5da5ca3_totalLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceived" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceived_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceived" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceived"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived" xlink:to="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceived" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DepreciationAndAmortization_019dbc7a-b30c-7cf8-a7f8-60e420470d08_terseLabel_en-US" xlink:label="lab_us-gaap_DepreciationAndAmortization" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Depreciation and amortization</link:label>
    <link:label id="lab_us-gaap_DepreciationAndAmortization_label_en-US" xlink:label="lab_us-gaap_DepreciationAndAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Depreciation, Depletion and Amortization, Nonproduction</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAndAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepreciationAndAmortization"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DepreciationAndAmortization" xlink:to="lab_us-gaap_DepreciationAndAmortization" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_PropertyManagementAgreementMember_019dbc7a-b286-7a4d-a230-847261fc7f76_terseLabel_en-US" xlink:label="lab_opi_PropertyManagementAgreementMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property management agreement</link:label>
    <link:label id="lab_opi_PropertyManagementAgreementMember_label_en-US" xlink:label="lab_opi_PropertyManagementAgreementMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property Management Agreement [Member]</link:label>
    <link:label id="lab_opi_PropertyManagementAgreementMember_documentation_en-US" xlink:label="lab_opi_PropertyManagementAgreementMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Property Management Agreement</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_PropertyManagementAgreementMember" xlink:href="opi-20251231.xsd#opi_PropertyManagementAgreementMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_PropertyManagementAgreementMember" xlink:to="lab_opi_PropertyManagementAgreementMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstatePolicyTextBlock_019dbc7a-b287-7bd4-83f3-64103929ccd2_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstatePolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate Properties</link:label>
    <link:label id="lab_us-gaap_RealEstatePolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_RealEstatePolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstatePolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstatePolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstatePolicyTextBlock" xlink:to="lab_us-gaap_RealEstatePolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateOtherDeductions_019dbc7a-b1cb-7a18-8229-197527a679f7_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_RealEstateOtherDeductions" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Cost basis adjustment</link:label>
    <link:label id="lab_us-gaap_RealEstateOtherDeductions_label_en-US" xlink:label="lab_us-gaap_RealEstateOtherDeductions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Other Deduction</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateOtherDeductions" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateOtherDeductions"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateOtherDeductions" xlink:to="lab_us-gaap_RealEstateOtherDeductions" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A446WrenplaceRoadFortMillSCMember_019dbc7a-b30c-74b1-ad92-69b706be4521_terseLabel_en-US" xlink:label="lab_opi_A446WrenplaceRoadFortMillSCMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">446 Wrenplace Road, Fort Mill, SC</link:label>
    <link:label id="lab_opi_A446WrenplaceRoadFortMillSCMember_label_en-US" xlink:label="lab_opi_A446WrenplaceRoadFortMillSCMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">446 Wrenplace Road, Fort Mill, SC [Member]</link:label>
    <link:label id="lab_opi_A446WrenplaceRoadFortMillSCMember_documentation_en-US" xlink:label="lab_opi_A446WrenplaceRoadFortMillSCMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">446 Wrenplace Road, Fort Mill, SC</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A446WrenplaceRoadFortMillSCMember" xlink:href="opi-20251231.xsd#opi_A446WrenplaceRoadFortMillSCMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A446WrenplaceRoadFortMillSCMember" xlink:to="lab_opi_A446WrenplaceRoadFortMillSCMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DebtInstrumentCovenantDistributionRateMaximum_019dbc7a-b1cb-713b-aa45-2e73d937a6ae_terseLabel_en-US" xlink:label="lab_opi_DebtInstrumentCovenantDistributionRateMaximum" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Distribution rate (in dollars per share)</link:label>
    <link:label id="lab_opi_DebtInstrumentCovenantDistributionRateMaximum_label_en-US" xlink:label="lab_opi_DebtInstrumentCovenantDistributionRateMaximum" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Distribution Rate, Maximum</link:label>
    <link:label id="lab_opi_DebtInstrumentCovenantDistributionRateMaximum_documentation_en-US" xlink:label="lab_opi_DebtInstrumentCovenantDistributionRateMaximum" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Distribution Rate, Maximum</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DebtInstrumentCovenantDistributionRateMaximum" xlink:href="opi-20251231.xsd#opi_DebtInstrumentCovenantDistributionRateMaximum"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DebtInstrumentCovenantDistributionRateMaximum" xlink:to="lab_opi_DebtInstrumentCovenantDistributionRateMaximum" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFour_019dbc7a-b287-7846-84ae-445bb046a665_terseLabel_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2029</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFour_label_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right, Exercisable In Year Four</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFour_documentation_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFour" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the percentage as a concentration risk for termination right exercisable in year four from the balance sheet date.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFour" xlink:href="opi-20251231.xsd#opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFour"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFour" xlink:to="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFour" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity_019dbc7a-b286-7951-a8c9-6fe0bfda1033_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity method investment, difference between carrying amount and underlying equity</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Difference Between Carrying Amount and Underlying Equity</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity" xlink:to="lab_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReconciliationOfCarryingAmountOfRealEstateInvestmentsRollForward_019dbc7a-b287-7a11-a165-6d403de8ec3e_terseLabel_en-US" xlink:label="lab_us-gaap_ReconciliationOfCarryingAmountOfRealEstateInvestmentsRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate Properties</link:label>
    <link:label id="lab_us-gaap_ReconciliationOfCarryingAmountOfRealEstateInvestmentsRollForward_label_en-US" xlink:label="lab_us-gaap_ReconciliationOfCarryingAmountOfRealEstateInvestmentsRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationOfCarryingAmountOfRealEstateInvestmentsRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReconciliationOfCarryingAmountOfRealEstateInvestmentsRollForward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReconciliationOfCarryingAmountOfRealEstateInvestmentsRollForward" xlink:to="lab_us-gaap_ReconciliationOfCarryingAmountOfRealEstateInvestmentsRollForward" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementOfCashFlowsAbstract_019dbc7a-b286-722a-810c-647b384d16f1_terseLabel_en-US" xlink:label="lab_us-gaap_StatementOfCashFlowsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statement of Cash Flows [Abstract]</link:label>
    <link:label id="lab_us-gaap_StatementOfCashFlowsAbstract_label_en-US" xlink:label="lab_us-gaap_StatementOfCashFlowsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Cash Flows [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfCashFlowsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementOfCashFlowsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract" xlink:to="lab_us-gaap_StatementOfCashFlowsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_CoSelectedMeasureAmt_terseLabel_en-US" xlink:label="lab_ecd_CoSelectedMeasureAmt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Company Selected Measure Amount</link:label>
    <link:label id="lab_ecd_CoSelectedMeasureAmt_label_en-US" xlink:label="lab_ecd_CoSelectedMeasureAmt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Company Selected Measure Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_CoSelectedMeasureAmt" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_CoSelectedMeasureAmt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_CoSelectedMeasureAmt" xlink:to="lab_ecd_CoSelectedMeasureAmt" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A7717MortgageNotesPayableMember_019dbcad-0d9e-7598-ad87-54149c7b6ffe_terseLabel_en-US" xlink:label="lab_opi_A7717MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mortgage note payable, 7.717% interest rate, due in 2033</link:label>
    <link:label id="lab_opi_A7717MortgageNotesPayableMember_label_en-US" xlink:label="lab_opi_A7717MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">7.717% Mortgage Notes Payable [Member]</link:label>
    <link:label id="lab_opi_A7717MortgageNotesPayableMember_documentation_en-US" xlink:label="lab_opi_A7717MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">7.717% Mortgage Notes Payable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A7717MortgageNotesPayableMember" xlink:href="opi-20251231.xsd#opi_A7717MortgageNotesPayableMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A7717MortgageNotesPayableMember" xlink:to="lab_opi_A7717MortgageNotesPayableMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredFinanceCostsGross_019dbc7a-b286-7155-83c4-3a97eae27053_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredFinanceCostsGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred financing fees, gross</link:label>
    <link:label id="lab_us-gaap_DeferredFinanceCostsGross_label_en-US" xlink:label="lab_us-gaap_DeferredFinanceCostsGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Issuance Costs, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsGross" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredFinanceCostsGross"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredFinanceCostsGross" xlink:to="lab_us-gaap_DeferredFinanceCostsGross" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_MeasureName_terseLabel_en-US" xlink:label="lab_ecd_MeasureName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Name</link:label>
    <link:label id="lab_ecd_MeasureName_label_en-US" xlink:label="lab_ecd_MeasureName" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Measure Name</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_MeasureName" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_MeasureName"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_MeasureName" xlink:to="lab_ecd_MeasureName" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SecuredDebtMember_019dbc7a-b1cb-7c97-bfc8-c025b35a8cbf_terseLabel_en-US" xlink:label="lab_us-gaap_SecuredDebtMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Secured Debt</link:label>
    <link:label id="lab_us-gaap_SecuredDebtMember_label_en-US" xlink:label="lab_us-gaap_SecuredDebtMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Secured Debt [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredDebtMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SecuredDebtMember" xlink:to="lab_us-gaap_SecuredDebtMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionPropertyManagementFeesAsPercentageOfGrossCollectedRents_019dbc7a-b286-7c3a-a938-fed9359e3a03_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionPropertyManagementFeesAsPercentageOfGrossCollectedRents" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Management fees as percentage of gross collected rents</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionPropertyManagementFeesAsPercentageOfGrossCollectedRents_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionPropertyManagementFeesAsPercentageOfGrossCollectedRents" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction Property Management Fees as Percentage of Gross Collected Rents</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionPropertyManagementFeesAsPercentageOfGrossCollectedRents_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionPropertyManagementFeesAsPercentageOfGrossCollectedRents" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the property management fees as a percentage of gross collected rents pursuant to property management agreement with related parties.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionPropertyManagementFeesAsPercentageOfGrossCollectedRents" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionPropertyManagementFeesAsPercentageOfGrossCollectedRents"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionPropertyManagementFeesAsPercentageOfGrossCollectedRents" xlink:to="lab_opi_RelatedPartyTransactionPropertyManagementFeesAsPercentageOfGrossCollectedRents" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_UnsecuredDebtMember_019dff22-7957-7abe-ae5c-1df117ac5b92_terseLabel_en-US" xlink:label="lab_us-gaap_UnsecuredDebtMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unsecured Debt</link:label>
    <link:label id="lab_us-gaap_UnsecuredDebtMember_label_en-US" xlink:label="lab_us-gaap_UnsecuredDebtMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Unsecured Debt [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnsecuredDebtMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_UnsecuredDebtMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UnsecuredDebtMember" xlink:to="lab_us-gaap_UnsecuredDebtMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A8305NW62ndAvenueJohnstonIAMember_019dbc7a-b286-7601-9e6d-a0a3ec274694_terseLabel_en-US" xlink:label="lab_opi_A8305NW62ndAvenueJohnstonIAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">8305 NW 62nd Avenue, Johnston, IA</link:label>
    <link:label id="lab_opi_A8305NW62ndAvenueJohnstonIAMember_label_en-US" xlink:label="lab_opi_A8305NW62ndAvenueJohnstonIAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">8305 NW 62nd Avenue, Johnston, IA [Member]</link:label>
    <link:label id="lab_opi_A8305NW62ndAvenueJohnstonIAMember_documentation_en-US" xlink:label="lab_opi_A8305NW62ndAvenueJohnstonIAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">8305 NW 62nd Avenue, Johnston, IA [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A8305NW62ndAvenueJohnstonIAMember" xlink:href="opi-20251231.xsd#opi_A8305NW62ndAvenueJohnstonIAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A8305NW62ndAvenueJohnstonIAMember" xlink:to="lab_opi_A8305NW62ndAvenueJohnstonIAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebt_019dbc7a-b1cb-7c73-8e10-bf6dea69a9aa_totalLabel_en-US" xlink:label="lab_us-gaap_LongTermDebt" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total borrowings outstanding</link:label>
    <link:label id="lab_us-gaap_LongTermDebt_019dbc7a-b1cb-79fb-a517-c8ae19371965_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Long-term debt</link:label>
    <link:label id="lab_us-gaap_LongTermDebt_019dbc7a-b1cb-774c-8437-7274215e353f_verboseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebt" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Total debt outstanding</link:label>
    <link:label id="lab_us-gaap_LongTermDebt_label_en-US" xlink:label="lab_us-gaap_LongTermDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebt" xlink:to="lab_us-gaap_LongTermDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_Assets_019dbc7a-b1cb-74e4-9b07-59394b81fd6b_totalLabel_en-US" xlink:label="lab_us-gaap_Assets" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total assets</link:label>
    <link:label id="lab_us-gaap_Assets_label_en-US" xlink:label="lab_us-gaap_Assets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Assets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Assets" xlink:to="lab_us-gaap_Assets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_019dbc7a-b1cb-733e-ade0-38316fe3326d_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2025</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Asset, Expected Amortization, Year One</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_019dbc7a-b287-7d8f-804f-b1edf5f59a5f_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vested (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateTable_019dbc7a-b30c-7d6b-a9f8-18499ea5cc06_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate [Table]</link:label>
    <link:label id="lab_us-gaap_RealEstateTable_label_en-US" xlink:label="lab_us-gaap_RealEstateTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateTable" xlink:to="lab_us-gaap_RealEstateTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy_019dbc7a-b287-7509-8f5c-b4eadd0d98b9_terseLabel_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Restricted Cash</link:label>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy_label_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy" xlink:to="lab_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_SegmentGeographicalDomain_019dbc7a-b287-76d0-b017-ebe245e19d52_terseLabel_en-US" xlink:label="lab_srt_SegmentGeographicalDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Geographical [Domain]</link:label>
    <link:label id="lab_srt_SegmentGeographicalDomain_label_en-US" xlink:label="lab_srt_SegmentGeographicalDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Geographical [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_SegmentGeographicalDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_SegmentGeographicalDomain" xlink:to="lab_srt_SegmentGeographicalDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxPolicyTextBlock_019dbc7a-b287-7a82-a33d-648eaf1c4255_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income Taxes</link:label>
    <link:label id="lab_us-gaap_IncomeTaxPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_IncomeTaxPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxPolicyTextBlock" xlink:to="lab_us-gaap_IncomeTaxPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_019dbc7a-b287-7699-8558-859902c64621_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">CASH FLOWS FROM OPERATING ACTIVITIES:</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardMarketValueOfSharesIssuedInPeriodToEachIndividual_019dbc7a-b287-7347-b65b-cc0506a071f0_terseLabel_en-US" xlink:label="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardMarketValueOfSharesIssuedInPeriodToEachIndividual" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Market value of common shares awarded to each trustee (in dollars)</link:label>
    <link:label id="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardMarketValueOfSharesIssuedInPeriodToEachIndividual_label_en-US" xlink:label="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardMarketValueOfSharesIssuedInPeriodToEachIndividual" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share Based Compensation Arrangement by Share Based Payment Award Market Value of Shares Issued in Period to Each Individual</link:label>
    <link:label id="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardMarketValueOfSharesIssuedInPeriodToEachIndividual_documentation_en-US" xlink:label="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardMarketValueOfSharesIssuedInPeriodToEachIndividual" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the market value of shares, newly issued during the reporting period under the plan, to each individual.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardMarketValueOfSharesIssuedInPeriodToEachIndividual" xlink:href="opi-20251231.xsd#opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardMarketValueOfSharesIssuedInPeriodToEachIndividual"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardMarketValueOfSharesIssuedInPeriodToEachIndividual" xlink:to="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardMarketValueOfSharesIssuedInPeriodToEachIndividual" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionRequiredEscrowDeposit_019dd0f9-e2c5-71c4-a901-0f069af57e27_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionRequiredEscrowDeposit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Escrow deposits required</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionRequiredEscrowDeposit_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionRequiredEscrowDeposit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Required Escrow Deposit</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionRequiredEscrowDeposit_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionRequiredEscrowDeposit" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Required Escrow Deposit</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionRequiredEscrowDeposit" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionRequiredEscrowDeposit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionRequiredEscrowDeposit" xlink:to="lab_opi_RelatedPartyTransactionRequiredEscrowDeposit" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ConcentrationRiskByTypeAxis_019dbc7a-b1cb-779e-a779-44952ebad122_terseLabel_en-US" xlink:label="lab_us-gaap_ConcentrationRiskByTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Concentration Risk Type [Axis]</link:label>
    <link:label id="lab_us-gaap_ConcentrationRiskByTypeAxis_label_en-US" xlink:label="lab_us-gaap_ConcentrationRiskByTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Type [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis" xlink:to="lab_us-gaap_ConcentrationRiskByTypeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateInvestmentPropertyAtCost_019dbc7a-b1cb-74ff-ab3c-5e32363d9d1b_totalLabel_en-US" xlink:label="lab_us-gaap_RealEstateInvestmentPropertyAtCost" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total real estate properties, gross</link:label>
    <link:label id="lab_us-gaap_RealEstateInvestmentPropertyAtCost_019dbc7a-b1cb-7274-8a13-5943c1c2004b_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateInvestmentPropertyAtCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real estate aggregate undepreciated carrying value</link:label>
    <link:label id="lab_us-gaap_RealEstateInvestmentPropertyAtCost_label_en-US" xlink:label="lab_us-gaap_RealEstateInvestmentPropertyAtCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Investment Property, at Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyAtCost" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateInvestmentPropertyAtCost"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateInvestmentPropertyAtCost" xlink:to="lab_us-gaap_RealEstateInvestmentPropertyAtCost" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_TenantWithExercisableTerminationRightsMember_019dbc7a-b1cb-77bc-b2f4-4e2b72fa4d5a_terseLabel_en-US" xlink:label="lab_opi_TenantWithExercisableTerminationRightsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tenant with Exercisable Termination Rights</link:label>
    <link:label id="lab_opi_TenantWithExercisableTerminationRightsMember_label_en-US" xlink:label="lab_opi_TenantWithExercisableTerminationRightsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tenant With Exercisable Termination Rights [Member]</link:label>
    <link:label id="lab_opi_TenantWithExercisableTerminationRightsMember_documentation_en-US" xlink:label="lab_opi_TenantWithExercisableTerminationRightsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tenant With Exercisable Termination Rights</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_TenantWithExercisableTerminationRightsMember" xlink:href="opi-20251231.xsd#opi_TenantWithExercisableTerminationRightsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_TenantWithExercisableTerminationRightsMember" xlink:to="lab_opi_TenantWithExercisableTerminationRightsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A9680OldBailesRoadFortMillSCMember_019dbc7a-b287-7d81-bccc-f938a6c4f9dc_terseLabel_en-US" xlink:label="lab_opi_A9680OldBailesRoadFortMillSCMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">9680 Old Bailes Road, Fort Mill, SC</link:label>
    <link:label id="lab_opi_A9680OldBailesRoadFortMillSCMember_label_en-US" xlink:label="lab_opi_A9680OldBailesRoadFortMillSCMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">9680 Old Bailes Road, Fort Mill, SC [Member]</link:label>
    <link:label id="lab_opi_A9680OldBailesRoadFortMillSCMember_documentation_en-US" xlink:label="lab_opi_A9680OldBailesRoadFortMillSCMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">9680 Old Bailes Road, Fort Mill, SC [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A9680OldBailesRoadFortMillSCMember" xlink:href="opi-20251231.xsd#opi_A9680OldBailesRoadFortMillSCMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A9680OldBailesRoadFortMillSCMember" xlink:to="lab_opi_A9680OldBailesRoadFortMillSCMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ShareBasedPaymentArrangementTrancheFiveMember_019dbc7a-b287-7923-a791-b2038cdba7c3_terseLabel_en-US" xlink:label="lab_opi_ShareBasedPaymentArrangementTrancheFiveMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement, Tranche 5</link:label>
    <link:label id="lab_opi_ShareBasedPaymentArrangementTrancheFiveMember_label_en-US" xlink:label="lab_opi_ShareBasedPaymentArrangementTrancheFiveMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement, Tranche Five [Member]</link:label>
    <link:label id="lab_opi_ShareBasedPaymentArrangementTrancheFiveMember_documentation_en-US" xlink:label="lab_opi_ShareBasedPaymentArrangementTrancheFiveMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement, Tranche Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ShareBasedPaymentArrangementTrancheFiveMember" xlink:href="opi-20251231.xsd#opi_ShareBasedPaymentArrangementTrancheFiveMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ShareBasedPaymentArrangementTrancheFiveMember" xlink:to="lab_opi_ShareBasedPaymentArrangementTrancheFiveMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_019dbc7a-b286-7a88-bf49-faf7a077a4b4_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2028</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Asset, Expected Amortization, Year Four</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityCommonStockSharesOutstanding_019dbc7a-b287-7e7a-949e-73dc3314add9_terseLabel_en-US" xlink:label="lab_dei_EntityCommonStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Common Stock, Shares Outstanding</link:label>
    <link:label id="lab_dei_EntityCommonStockSharesOutstanding_label_en-US" xlink:label="lab_dei_EntityCommonStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Common Stock, Shares Outstanding</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityCommonStockSharesOutstanding" xlink:to="lab_dei_EntityCommonStockSharesOutstanding" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayable_019dbc7a-b1cb-7028-a17f-7d8ed49ab1f1_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage for limitation and adjustments of incentive management fee payable</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayable_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction Percentage For Limitation and Adjustments Of Incentive Management Fee Payable</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayable_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the incentive management fee payable as a percentage of the product of the entity's equity market capitalization and its share price appreciation plus dividends.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayable" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayable" xlink:to="lab_opi_RelatedPartyTransactionPercentageForLimitationAndAdjustmentsOfIncentiveManagementFeePayable" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_IncentiveManagementFeeAverageClosingPriceDuringThresholdConsecutiveTradingDays_019dbc7a-b1cb-7aba-b830-6c5d901b9b6c_terseLabel_en-US" xlink:label="lab_opi_IncentiveManagementFeeAverageClosingPriceDuringThresholdConsecutiveTradingDays" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Average closing price of our common shares, consecutive trading days</link:label>
    <link:label id="lab_opi_IncentiveManagementFeeAverageClosingPriceDuringThresholdConsecutiveTradingDays_label_en-US" xlink:label="lab_opi_IncentiveManagementFeeAverageClosingPriceDuringThresholdConsecutiveTradingDays" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Incentive Management Fee, Average Closing Price During Threshold Consecutive Trading Days</link:label>
    <link:label id="lab_opi_IncentiveManagementFeeAverageClosingPriceDuringThresholdConsecutiveTradingDays_documentation_en-US" xlink:label="lab_opi_IncentiveManagementFeeAverageClosingPriceDuringThresholdConsecutiveTradingDays" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Incentive Management Fee, Average Closing Price During Threshold Consecutive Trading Days</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_IncentiveManagementFeeAverageClosingPriceDuringThresholdConsecutiveTradingDays" xlink:href="opi-20251231.xsd#opi_IncentiveManagementFeeAverageClosingPriceDuringThresholdConsecutiveTradingDays"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_IncentiveManagementFeeAverageClosingPriceDuringThresholdConsecutiveTradingDays" xlink:to="lab_opi_IncentiveManagementFeeAverageClosingPriceDuringThresholdConsecutiveTradingDays" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentFinStmtErrorCorrectionFlag_019dbc7a-b287-7899-913d-e9e446d269bb_terseLabel_en-US" xlink:label="lab_dei_DocumentFinStmtErrorCorrectionFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Document Financial Statement Error Correction [Flag]</link:label>
    <link:label id="lab_dei_DocumentFinStmtErrorCorrectionFlag_label_en-US" xlink:label="lab_dei_DocumentFinStmtErrorCorrectionFlag" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Document Financial Statement Error Correction [Flag]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFinStmtErrorCorrectionFlag" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentFinStmtErrorCorrectionFlag"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentFinStmtErrorCorrectionFlag" xlink:to="lab_dei_DocumentFinStmtErrorCorrectionFlag" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A2544CampbellPlaceCarlsbadCAMember_019dbc7a-b1cb-7ba1-a2f5-4165cb99ced9_terseLabel_en-US" xlink:label="lab_opi_A2544CampbellPlaceCarlsbadCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2544 Campbell Place, Carlsbad, CA</link:label>
    <link:label id="lab_opi_A2544CampbellPlaceCarlsbadCAMember_label_en-US" xlink:label="lab_opi_A2544CampbellPlaceCarlsbadCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2544 Campbell Place, Carlsbad, CA [Member]</link:label>
    <link:label id="lab_opi_A2544CampbellPlaceCarlsbadCAMember_documentation_en-US" xlink:label="lab_opi_A2544CampbellPlaceCarlsbadCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2544 Campbell Place, Carlsbad, CA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A2544CampbellPlaceCarlsbadCAMember" xlink:href="opi-20251231.xsd#opi_A2544CampbellPlaceCarlsbadCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A2544CampbellPlaceCarlsbadCAMember" xlink:to="lab_opi_A2544CampbellPlaceCarlsbadCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityMethodInvestments_019dbc7a-b30c-71e2-941e-30f76053ef9a_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">OPI Carrying Value of Investments</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestments_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestments" xlink:to="lab_us-gaap_EquityMethodInvestments" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_InsiderTrdPoliciesProcNotAdoptedTextBlock_terseLabel_en-US" xlink:label="lab_ecd_InsiderTrdPoliciesProcNotAdoptedTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Insider Trading Policies and Procedures Not Adopted</link:label>
    <link:label id="lab_ecd_InsiderTrdPoliciesProcNotAdoptedTextBlock_label_en-US" xlink:label="lab_ecd_InsiderTrdPoliciesProcNotAdoptedTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Insider Trading Policies and Procedures Not Adopted [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_InsiderTrdPoliciesProcNotAdoptedTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_InsiderTrdPoliciesProcNotAdoptedTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_InsiderTrdPoliciesProcNotAdoptedTextBlock" xlink:to="lab_ecd_InsiderTrdPoliciesProcNotAdoptedTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A350WestJavaDriveSunnyvaleCAMember_019dbc7a-b1cb-7423-9434-7946ff2b6bb0_terseLabel_en-US" xlink:label="lab_opi_A350WestJavaDriveSunnyvaleCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">350 West Java Drive, Sunnyvale, CA</link:label>
    <link:label id="lab_opi_A350WestJavaDriveSunnyvaleCAMember_label_en-US" xlink:label="lab_opi_A350WestJavaDriveSunnyvaleCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">350 West Java Drive, Sunnyvale, CA [Member]</link:label>
    <link:label id="lab_opi_A350WestJavaDriveSunnyvaleCAMember_documentation_en-US" xlink:label="lab_opi_A350WestJavaDriveSunnyvaleCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">350 West Java Drive, Sunnyvale, CA [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A350WestJavaDriveSunnyvaleCAMember" xlink:href="opi-20251231.xsd#opi_A350WestJavaDriveSunnyvaleCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A350WestJavaDriveSunnyvaleCAMember" xlink:to="lab_opi_A350WestJavaDriveSunnyvaleCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DebtInstrumentAmountAvailableToBeDrawn_019dd612-67ed-7d6d-a6c6-b82f1aa3feb1_terseLabel_en-US" xlink:label="lab_opi_DebtInstrumentAmountAvailableToBeDrawn" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amount available to be drawn under credit agreement</link:label>
    <link:label id="lab_opi_DebtInstrumentAmountAvailableToBeDrawn_label_en-US" xlink:label="lab_opi_DebtInstrumentAmountAvailableToBeDrawn" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Amount Available To Be Drawn</link:label>
    <link:label id="lab_opi_DebtInstrumentAmountAvailableToBeDrawn_documentation_en-US" xlink:label="lab_opi_DebtInstrumentAmountAvailableToBeDrawn" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Amount Available To Be Drawn</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DebtInstrumentAmountAvailableToBeDrawn" xlink:href="opi-20251231.xsd#opi_DebtInstrumentAmountAvailableToBeDrawn"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DebtInstrumentAmountAvailableToBeDrawn" xlink:to="lab_opi_DebtInstrumentAmountAvailableToBeDrawn" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RelatedPartyMember_019dbc7a-b287-729c-8e11-570290c05a79_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Related Party</link:label>
    <link:label id="lab_us-gaap_RelatedPartyMember_label_en-US" xlink:label="lab_us-gaap_RelatedPartyMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyMember" xlink:to="lab_us-gaap_RelatedPartyMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A7987AshtonAvenueManassasVAMember_019dbc7a-b1cb-7e70-8206-a0ff2c56d5e7_terseLabel_en-US" xlink:label="lab_opi_A7987AshtonAvenueManassasVAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">7987 Ashton Avenue, Manassas, VA</link:label>
    <link:label id="lab_opi_A7987AshtonAvenueManassasVAMember_label_en-US" xlink:label="lab_opi_A7987AshtonAvenueManassasVAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">7987 Ashton Avenue, Manassas, VA [Member]</link:label>
    <link:label id="lab_opi_A7987AshtonAvenueManassasVAMember_documentation_en-US" xlink:label="lab_opi_A7987AshtonAvenueManassasVAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">7987 Ashton avenue [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A7987AshtonAvenueManassasVAMember" xlink:href="opi-20251231.xsd#opi_A7987AshtonAvenueManassasVAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A7987AshtonAvenueManassasVAMember" xlink:to="lab_opi_A7987AshtonAvenueManassasVAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LiabilitiesSubjectToCompromiseTableTextBlock_019dd0b6-6784-771f-ab51-ea6fbcf587c8_terseLabel_en-US" xlink:label="lab_opi_LiabilitiesSubjectToCompromiseTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Liabilities Subject to Compromise</link:label>
    <link:label id="lab_opi_LiabilitiesSubjectToCompromiseTableTextBlock_label_en-US" xlink:label="lab_opi_LiabilitiesSubjectToCompromiseTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities Subject To Compromise [Table Text Block]</link:label>
    <link:label id="lab_opi_LiabilitiesSubjectToCompromiseTableTextBlock_documentation_en-US" xlink:label="lab_opi_LiabilitiesSubjectToCompromiseTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Liabilities Subject To Compromise</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LiabilitiesSubjectToCompromiseTableTextBlock" xlink:href="opi-20251231.xsd#opi_LiabilitiesSubjectToCompromiseTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LiabilitiesSubjectToCompromiseTableTextBlock" xlink:to="lab_opi_LiabilitiesSubjectToCompromiseTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PlanNameAxis_019dbc7a-b1cb-7934-b6a3-9c3b7ef8ee24_terseLabel_en-US" xlink:label="lab_us-gaap_PlanNameAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Plan Name [Axis]</link:label>
    <link:label id="lab_us-gaap_PlanNameAxis_label_en-US" xlink:label="lab_us-gaap_PlanNameAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Plan Name [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanNameAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PlanNameAxis" xlink:to="lab_us-gaap_PlanNameAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearThree_019dbc7a-b287-758c-9faf-642225bc96ad_terseLabel_en-US" xlink:label="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2028 (in shares)</link:label>
    <link:label id="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearThree_label_en-US" xlink:label="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share Based Compensation Arrangement By Share Based Payment Award, Nonvested Shares Scheduled To Vest In Year Three</link:label>
    <link:label id="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearThree_documentation_en-US" xlink:label="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearThree" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of non-vested shares that are scheduled to vest in year three.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearThree" xlink:href="opi-20251231.xsd#opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearThree"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearThree" xlink:to="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearThree" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_PeoMember_terseLabel_en-US" xlink:label="lab_ecd_PeoMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">PEO</link:label>
    <link:label id="lab_ecd_PeoMember_label_en-US" xlink:label="lab_ecd_PeoMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">PEO [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_PeoMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_PeoMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_PeoMember" xlink:to="lab_ecd_PeoMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LiabilitiesSubjectToCompromisePolicyPolicyTextBlock_019dd0b3-61b2-7488-a28b-20002819ff88_terseLabel_en-US" xlink:label="lab_opi_LiabilitiesSubjectToCompromisePolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Liabilities Subject to Compromise</link:label>
    <link:label id="lab_opi_LiabilitiesSubjectToCompromisePolicyPolicyTextBlock_label_en-US" xlink:label="lab_opi_LiabilitiesSubjectToCompromisePolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities Subject To Compromise, Policy [Policy Text Block]</link:label>
    <link:label id="lab_opi_LiabilitiesSubjectToCompromisePolicyPolicyTextBlock_documentation_en-US" xlink:label="lab_opi_LiabilitiesSubjectToCompromisePolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Liabilities Subject To Compromise, Policy</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LiabilitiesSubjectToCompromisePolicyPolicyTextBlock" xlink:href="opi-20251231.xsd#opi_LiabilitiesSubjectToCompromisePolicyPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LiabilitiesSubjectToCompromisePolicyPolicyTextBlock" xlink:to="lab_opi_LiabilitiesSubjectToCompromisePolicyPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_OneGeorgiaCenterAtlantaGAMember_019dbc7a-b287-7f2f-acc8-334a1a78d1f2_terseLabel_en-US" xlink:label="lab_opi_OneGeorgiaCenterAtlantaGAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">One Georgia Center, Atlanta, GA</link:label>
    <link:label id="lab_opi_OneGeorgiaCenterAtlantaGAMember_label_en-US" xlink:label="lab_opi_OneGeorgiaCenterAtlantaGAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">One Georgia Center, Atlanta, GA [Member]</link:label>
    <link:label id="lab_opi_OneGeorgiaCenterAtlantaGAMember_documentation_en-US" xlink:label="lab_opi_OneGeorgiaCenterAtlantaGAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents information pertaining to One Georgia Center, located in Atlanta, Georgia.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_OneGeorgiaCenterAtlantaGAMember" xlink:href="opi-20251231.xsd#opi_OneGeorgiaCenterAtlantaGAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_OneGeorgiaCenterAtlantaGAMember" xlink:to="lab_opi_OneGeorgiaCenterAtlantaGAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_019dbc7e-e103-7e2c-958f-675aeff118fb_totalLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Loss before income tax expense and equity in net losses of investees</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:to="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionAnnualFeePeriod_019dd5fb-be51-782b-8d7a-2ddf53e9939d_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionAnnualFeePeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Annual fee period</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionAnnualFeePeriod_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionAnnualFeePeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Annual Fee Period</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionAnnualFeePeriod_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionAnnualFeePeriod" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Annual Fee Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionAnnualFeePeriod" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionAnnualFeePeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionAnnualFeePeriod" xlink:to="lab_opi_RelatedPartyTransactionAnnualFeePeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_019dbc87-c26a-752b-8609-32f42bfa19cd_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Change in assets and liabilities:</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateReclassificationAssetsHeldForSale_019dbc7a-b1cb-77ee-bf21-189d5afe881d_negatedTerseLabel_en-US" xlink:label="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateReclassificationAssetsHeldForSale" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Reclassification of assets of properties held for sale</link:label>
    <link:label id="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateReclassificationAssetsHeldForSale_label_en-US" xlink:label="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateReclassificationAssetsHeldForSale" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment In Real Estate, Reclassification Assets Held For Sale</link:label>
    <link:label id="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateReclassificationAssetsHeldForSale_documentation_en-US" xlink:label="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateReclassificationAssetsHeldForSale" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amount of deductions for reclassification of real estate investments assets held for sale, excluding sales, for entities with a substantial portion of business acquiring and holding investment real estate.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateReclassificationAssetsHeldForSale" xlink:href="opi-20251231.xsd#opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateReclassificationAssetsHeldForSale"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateReclassificationAssetsHeldForSale" xlink:to="lab_opi_SECSchedule1228RealEstateCompaniesInvestmentInRealEstateReclassificationAssetsHeldForSale" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_UtilitiesOperatingExpense_019dbc7a-b287-7609-be1b-f16991a7de1d_terseLabel_en-US" xlink:label="lab_us-gaap_UtilitiesOperatingExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Utility expenses</link:label>
    <link:label id="lab_us-gaap_UtilitiesOperatingExpense_label_en-US" xlink:label="lab_us-gaap_UtilitiesOperatingExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Utilities Operating Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UtilitiesOperatingExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_UtilitiesOperatingExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UtilitiesOperatingExpense" xlink:to="lab_us-gaap_UtilitiesOperatingExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RetainedEarningsMember_019dbc7a-b1cb-7aae-90c7-2047bd9837ca_terseLabel_en-US" xlink:label="lab_us-gaap_RetainedEarningsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cumulative Net Income (Loss)</link:label>
    <link:label id="lab_us-gaap_RetainedEarningsMember_label_en-US" xlink:label="lab_us-gaap_RetainedEarningsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retained Earnings [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetainedEarningsMember" xlink:to="lab_us-gaap_RetainedEarningsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_MaximumThresholdPercentageOfOutstandingVotingSharesAfterBankruptcyTriggeringFreshStartReporting_019e2c1a-79ea-79d1-bf09-1616482c83ac_terseLabel_en-US" xlink:label="lab_opi_MaximumThresholdPercentageOfOutstandingVotingSharesAfterBankruptcyTriggeringFreshStartReporting" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage of outstanding voting shares of reorganized company following emergency from bankruptcy to qualify as fresh-start reporting</link:label>
    <link:label id="lab_opi_MaximumThresholdPercentageOfOutstandingVotingSharesAfterBankruptcyTriggeringFreshStartReporting_label_en-US" xlink:label="lab_opi_MaximumThresholdPercentageOfOutstandingVotingSharesAfterBankruptcyTriggeringFreshStartReporting" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Maximum Threshold Percentage Of Outstanding Voting Shares After Bankruptcy Triggering Fresh-Start Reporting</link:label>
    <link:label id="lab_opi_MaximumThresholdPercentageOfOutstandingVotingSharesAfterBankruptcyTriggeringFreshStartReporting_documentation_en-US" xlink:label="lab_opi_MaximumThresholdPercentageOfOutstandingVotingSharesAfterBankruptcyTriggeringFreshStartReporting" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Maximum Threshold Percentage Of Outstanding Voting Shares After Bankruptcy Triggering Fresh-Start Reporting</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_MaximumThresholdPercentageOfOutstandingVotingSharesAfterBankruptcyTriggeringFreshStartReporting" xlink:href="opi-20251231.xsd#opi_MaximumThresholdPercentageOfOutstandingVotingSharesAfterBankruptcyTriggeringFreshStartReporting"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_MaximumThresholdPercentageOfOutstandingVotingSharesAfterBankruptcyTriggeringFreshStartReporting" xlink:to="lab_opi_MaximumThresholdPercentageOfOutstandingVotingSharesAfterBankruptcyTriggeringFreshStartReporting" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019dbc8d-ef59-767b-b074-d75a5cc889d2_periodStartLabel_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Cash, cash equivalents and restricted cash at beginning of period</link:label>
    <link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019dbc8d-f575-7ad6-b362-632cb22323bb_periodEndLabel_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Cash, cash equivalents and restricted cash at end of period</link:label>
    <link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019dbc8e-598e-7c85-95d1-0a6efb1a780d_totalLabel_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total cash, cash equivalents and restricted cash shown in the condensed consolidated statements of cash flows</link:label>
    <link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_label_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:to="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeStatementAbstract_019dbc7a-b286-7df0-a583-a07125014d4e_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeStatementAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income Statement [Abstract]</link:label>
    <link:label id="lab_us-gaap_IncomeStatementAbstract_label_en-US" xlink:label="lab_us-gaap_IncomeStatementAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Statement [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeStatementAbstract" xlink:to="lab_us-gaap_IncomeStatementAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LongTermDebtEquityRightsOfferingAmount_019dff2e-e160-7ebd-9c30-04dd7cc7bb5d_terseLabel_en-US" xlink:label="lab_opi_LongTermDebtEquityRightsOfferingAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate amount of equity rights offering</link:label>
    <link:label id="lab_opi_LongTermDebtEquityRightsOfferingAmount_label_en-US" xlink:label="lab_opi_LongTermDebtEquityRightsOfferingAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Equity Rights Offering, Amount</link:label>
    <link:label id="lab_opi_LongTermDebtEquityRightsOfferingAmount_documentation_en-US" xlink:label="lab_opi_LongTermDebtEquityRightsOfferingAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Equity Rights Offering, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LongTermDebtEquityRightsOfferingAmount" xlink:href="opi-20251231.xsd#opi_LongTermDebtEquityRightsOfferingAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LongTermDebtEquityRightsOfferingAmount" xlink:to="lab_opi_LongTermDebtEquityRightsOfferingAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SaleOfStockNameOfTransactionDomain_019dbc7a-b287-769b-ae98-4031ab4139db_terseLabel_en-US" xlink:label="lab_us-gaap_SaleOfStockNameOfTransactionDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sale of Stock [Domain]</link:label>
    <link:label id="lab_us-gaap_SaleOfStockNameOfTransactionDomain_label_en-US" xlink:label="lab_us-gaap_SaleOfStockNameOfTransactionDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale of Stock [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain" xlink:to="lab_us-gaap_SaleOfStockNameOfTransactionDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionAmortizationOfLiability_019dbc7a-b1cb-7b07-a01b-77e4f16c3c9f_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionAmortizationOfLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Recognized amortization of the liability</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionAmortizationOfLiability_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionAmortizationOfLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction Amortization Of Liability</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionAmortizationOfLiability_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionAmortizationOfLiability" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of amortization of the liability recorded during the period.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionAmortizationOfLiability" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionAmortizationOfLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionAmortizationOfLiability" xlink:to="lab_opi_RelatedPartyTransactionAmortizationOfLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_MeasurementPeriodForIncentiveManagementFee_019dbc7a-b286-78ca-9e2f-e3855a4d7fb0_terseLabel_en-US" xlink:label="lab_opi_MeasurementPeriodForIncentiveManagementFee" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Measurement period for incentive management fee</link:label>
    <link:label id="lab_opi_MeasurementPeriodForIncentiveManagementFee_label_en-US" xlink:label="lab_opi_MeasurementPeriodForIncentiveManagementFee" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Measurement Period For Incentive Management Fee</link:label>
    <link:label id="lab_opi_MeasurementPeriodForIncentiveManagementFee_documentation_en-US" xlink:label="lab_opi_MeasurementPeriodForIncentiveManagementFee" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The measurement periods generally speaking and ending with the year for which the incentive management fee is being calculated, with shorter periods applicable in the case of the calculation of the incentive management fee for 2014 (one year) and 2015 (two years).</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_MeasurementPeriodForIncentiveManagementFee" xlink:href="opi-20251231.xsd#opi_MeasurementPeriodForIncentiveManagementFee"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_MeasurementPeriodForIncentiveManagementFee" xlink:to="lab_opi_MeasurementPeriodForIncentiveManagementFee" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFive_019dbc7a-b287-72f7-a7d2-56fca51f3294_terseLabel_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2030</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFive_label_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right Exercisable In Year Five</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFive_documentation_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFive" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the percentage as a concentration risk for termination right exercisable in year five from the balance sheet date.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFive" xlink:href="opi-20251231.xsd#opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFive" xlink:to="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AboveMarketLeasesMember_019dbc7a-b287-796a-a83a-fd1b84c6459d_terseLabel_en-US" xlink:label="lab_us-gaap_AboveMarketLeasesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Above Market Lease</link:label>
    <link:label id="lab_us-gaap_AboveMarketLeasesMember_label_en-US" xlink:label="lab_us-gaap_AboveMarketLeasesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Above Market Leases [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AboveMarketLeasesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AboveMarketLeasesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AboveMarketLeasesMember" xlink:to="lab_us-gaap_AboveMarketLeasesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CustomerConcentrationRiskMember_019dbc7a-b286-734c-8de8-b7062dfb08f9_terseLabel_en-US" xlink:label="lab_us-gaap_CustomerConcentrationRiskMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tenant Concentration</link:label>
    <link:label id="lab_us-gaap_CustomerConcentrationRiskMember_label_en-US" xlink:label="lab_us-gaap_CustomerConcentrationRiskMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Customer Concentration Risk [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CustomerConcentrationRiskMember" xlink:to="lab_us-gaap_CustomerConcentrationRiskMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ShareAwardPlanMember_019dbc7a-b287-7006-a381-daa35880bbb1_terseLabel_en-US" xlink:label="lab_opi_ShareAwardPlanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2009 Award Plan</link:label>
    <link:label id="lab_opi_ShareAwardPlanMember_label_en-US" xlink:label="lab_opi_ShareAwardPlanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share Award Plan [Member]</link:label>
    <link:label id="lab_opi_ShareAwardPlanMember_documentation_en-US" xlink:label="lab_opi_ShareAwardPlanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the share award plan adopted in 2009, or the Award Plan.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ShareAwardPlanMember" xlink:href="opi-20251231.xsd#opi_ShareAwardPlanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ShareAwardPlanMember" xlink:to="lab_opi_ShareAwardPlanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A14668LeeRoadChantillyVAMember_019dbc7a-b287-7feb-9934-2bbbc9e30152_terseLabel_en-US" xlink:label="lab_opi_A14668LeeRoadChantillyVAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">14668 Lee Road, Chantilly, VA</link:label>
    <link:label id="lab_opi_A14668LeeRoadChantillyVAMember_label_en-US" xlink:label="lab_opi_A14668LeeRoadChantillyVAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">14668 Lee Road, Chantilly, VA [Member]</link:label>
    <link:label id="lab_opi_A14668LeeRoadChantillyVAMember_documentation_en-US" xlink:label="lab_opi_A14668LeeRoadChantillyVAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">14668 Lee Road, Chantilly, VA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A14668LeeRoadChantillyVAMember" xlink:href="opi-20251231.xsd#opi_A14668LeeRoadChantillyVAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A14668LeeRoadChantillyVAMember" xlink:to="lab_opi_A14668LeeRoadChantillyVAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears_019dbc7a-b1cb-7362-8cf0-9e6c4b4c67f1_terseLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2028</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received, Year Three</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears" xlink:to="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_RestatementDoesNotRequireRecoveryTextBlock_terseLabel_en-US" xlink:label="lab_ecd_RestatementDoesNotRequireRecoveryTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Restatement does not require Recovery</link:label>
    <link:label id="lab_ecd_RestatementDoesNotRequireRecoveryTextBlock_label_en-US" xlink:label="lab_ecd_RestatementDoesNotRequireRecoveryTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Restatement Does Not Require Recovery [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_RestatementDoesNotRequireRecoveryTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_RestatementDoesNotRequireRecoveryTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_RestatementDoesNotRequireRecoveryTextBlock" xlink:to="lab_ecd_RestatementDoesNotRequireRecoveryTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RosedaleCorporatePlazaRosevilleMNMember_019dbc7a-b287-7dbc-8b15-2137991af7bc_terseLabel_en-US" xlink:label="lab_opi_RosedaleCorporatePlazaRosevilleMNMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rosedale Corporate Plaza, Roseville, MN</link:label>
    <link:label id="lab_opi_RosedaleCorporatePlazaRosevilleMNMember_label_en-US" xlink:label="lab_opi_RosedaleCorporatePlazaRosevilleMNMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Rosedale Corporate Plaza, Roseville, MN [Member]</link:label>
    <link:label id="lab_opi_RosedaleCorporatePlazaRosevilleMNMember_documentation_en-US" xlink:label="lab_opi_RosedaleCorporatePlazaRosevilleMNMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents information pertaining to Rosedale Corporate Plaza, located in Roseville, Minnesota.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RosedaleCorporatePlazaRosevilleMNMember" xlink:href="opi-20251231.xsd#opi_RosedaleCorporatePlazaRosevilleMNMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RosedaleCorporatePlazaRosevilleMNMember" xlink:to="lab_opi_RosedaleCorporatePlazaRosevilleMNMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_019dbc7a-b287-7995-bb33-e618e46bcb87_terseLabel_en-US" xlink:label="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Organization, Consolidation and Presentation of Financial Statements [Abstract]</link:label>
    <link:label id="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_label_en-US" xlink:label="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Organization, Consolidation and Presentation of Financial Statements [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:to="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A251CausewayStreetBostonMAMember_019dbc7a-b286-7e9a-8121-84306c2420bd_terseLabel_en-US" xlink:label="lab_opi_A251CausewayStreetBostonMAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">251 Causeway Street, Boston, MA</link:label>
    <link:label id="lab_opi_A251CausewayStreetBostonMAMember_label_en-US" xlink:label="lab_opi_A251CausewayStreetBostonMAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">251 Causeway Street, Boston, MA [Member]</link:label>
    <link:label id="lab_opi_A251CausewayStreetBostonMAMember_documentation_en-US" xlink:label="lab_opi_A251CausewayStreetBostonMAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">251 Causeway Street, Boston, MA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A251CausewayStreetBostonMAMember" xlink:href="opi-20251231.xsd#opi_A251CausewayStreetBostonMAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A251CausewayStreetBostonMAMember" xlink:to="lab_opi_A251CausewayStreetBostonMAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRentIncreasePeriod_019dbc7a-b1cb-7aae-ac6a-b38e4e6d83a4_terseLabel_en-US" xlink:label="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRentIncreasePeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Annual base rent increase</link:label>
    <link:label id="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRentIncreasePeriod_label_en-US" xlink:label="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRentIncreasePeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Lease Not yet Commenced, Annual Base Rent Increase Period</link:label>
    <link:label id="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRentIncreasePeriod_documentation_en-US" xlink:label="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRentIncreasePeriod" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Lease Not yet Commenced, Annual Base Rent Increase Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRentIncreasePeriod" xlink:href="opi-20251231.xsd#opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRentIncreasePeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRentIncreasePeriod" xlink:to="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRentIncreasePeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_CityAreaCode_019dbc7a-b287-7181-a96b-cf0f2ae9dd6f_terseLabel_en-US" xlink:label="lab_dei_CityAreaCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">City Area Code</link:label>
    <link:label id="lab_dei_CityAreaCode_label_en-US" xlink:label="lab_dei_CityAreaCode" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">City Area Code</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CityAreaCode"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_CityAreaCode" xlink:to="lab_dei_CityAreaCode" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A2500WalshAvenueSantaClaraCAMember_019dbc7a-b1cb-78a8-a656-e2ef382dfc04_terseLabel_en-US" xlink:label="lab_opi_A2500WalshAvenueSantaClaraCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2500 Walsh Avenue, Santa Clara, CA</link:label>
    <link:label id="lab_opi_A2500WalshAvenueSantaClaraCAMember_label_en-US" xlink:label="lab_opi_A2500WalshAvenueSantaClaraCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2500 Walsh Avenue, Santa Clara, CA [Member]</link:label>
    <link:label id="lab_opi_A2500WalshAvenueSantaClaraCAMember_documentation_en-US" xlink:label="lab_opi_A2500WalshAvenueSantaClaraCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2500 Walsh Avenue, Santa Clara, CA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A2500WalshAvenueSantaClaraCAMember" xlink:href="opi-20251231.xsd#opi_A2500WalshAvenueSantaClaraCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A2500WalshAvenueSantaClaraCAMember" xlink:to="lab_opi_A2500WalshAvenueSantaClaraCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AwardTmgHowMnpiCnsdrdTextBlock_terseLabel_en-US" xlink:label="lab_ecd_AwardTmgHowMnpiCnsdrdTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Award Timing, How MNPI Considered</link:label>
    <link:label id="lab_ecd_AwardTmgHowMnpiCnsdrdTextBlock_label_en-US" xlink:label="lab_ecd_AwardTmgHowMnpiCnsdrdTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Award Timing, How MNPI Considered [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AwardTmgHowMnpiCnsdrdTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AwardTmgHowMnpiCnsdrdTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AwardTmgHowMnpiCnsdrdTextBlock" xlink:to="lab_ecd_AwardTmgHowMnpiCnsdrdTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_MortgagesMember_019dbc7a-b287-7e7e-98c1-ccf08d450d5f_terseLabel_en-US" xlink:label="lab_us-gaap_MortgagesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mortgage notes payable</link:label>
    <link:label id="lab_us-gaap_MortgagesMember_label_en-US" xlink:label="lab_us-gaap_MortgagesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mortgages [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgagesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MortgagesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MortgagesMember" xlink:to="lab_us-gaap_MortgagesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRent_019dbc7a-b1cb-7792-a971-794e8d6a87e5_terseLabel_en-US" xlink:label="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Annual base rent</link:label>
    <link:label id="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRent_label_en-US" xlink:label="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Lease Not yet Commenced, Annual Base Rent</link:label>
    <link:label id="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRent_documentation_en-US" xlink:label="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRent" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Lease Not yet Commenced, Annual Base Rent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRent" xlink:href="opi-20251231.xsd#opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRent" xlink:to="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualBaseRent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProceedsFromLongTermLinesOfCredit_019dbc8d-31fb-79b0-b2d0-46b92e2badf8_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromLongTermLinesOfCredit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Borrowings on revolving credit facility</link:label>
    <link:label id="lab_us-gaap_ProceedsFromLongTermLinesOfCredit_label_en-US" xlink:label="lab_us-gaap_ProceedsFromLongTermLinesOfCredit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Long-Term Lines of Credit</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromLongTermLinesOfCredit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromLongTermLinesOfCredit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromLongTermLinesOfCredit" xlink:to="lab_us-gaap_ProceedsFromLongTermLinesOfCredit" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_019dbc7a-b286-7133-b913-f8419bd7a8c1_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">CASH FLOWS FROM INVESTING ACTIVITIES:</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:to="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GeneralAndAdministrativeExpense_019dbc7a-b1cb-7ad8-a427-014167124203_terseLabel_en-US" xlink:label="lab_us-gaap_GeneralAndAdministrativeExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">General and administrative</link:label>
    <link:label id="lab_us-gaap_GeneralAndAdministrativeExpense_label_en-US" xlink:label="lab_us-gaap_GeneralAndAdministrativeExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">General and Administrative Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GeneralAndAdministrativeExpense" xlink:to="lab_us-gaap_GeneralAndAdministrativeExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_PvpTable_terseLabel_en-US" xlink:label="lab_ecd_PvpTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pay vs Performance Disclosure</link:label>
    <link:label id="lab_ecd_PvpTable_label_en-US" xlink:label="lab_ecd_PvpTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pay vs Performance Disclosure [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_PvpTable" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_PvpTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_PvpTable" xlink:to="lab_ecd_PvpTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_019dbc7a-b286-77be-b48d-a8cce53e539a_terseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Disposal Group, Disposed of by Sale</link:label>
    <link:label id="lab_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_label_en-US" xlink:label="lab_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember" xlink:to="lab_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RelatedPartyTransactionsAbstract_019dbc7a-b1cb-72b6-ac3c-4668087d31ca_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Related Party Transactions [Abstract]</link:label>
    <link:label id="lab_us-gaap_RelatedPartyTransactionsAbstract_label_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transactions [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyTransactionsAbstract" xlink:to="lab_us-gaap_RelatedPartyTransactionsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherLiabilities_019dbc7a-b30c-71b1-a07f-45ac171771ff_terseLabel_en-US" xlink:label="lab_us-gaap_OtherLiabilities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts payable and other liabilities</link:label>
    <link:label id="lab_us-gaap_OtherLiabilities_label_en-US" xlink:label="lab_us-gaap_OtherLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Liabilities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherLiabilities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherLiabilities" xlink:to="lab_us-gaap_OtherLiabilities" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_SECScheduleIIIRealEstateNumberOfUnits_019dbc7a-b1cb-7bfb-83d5-f52abd13b2d7_terseLabel_en-US" xlink:label="lab_srt_SECScheduleIIIRealEstateNumberOfUnits" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of Properties</link:label>
    <link:label id="lab_srt_SECScheduleIIIRealEstateNumberOfUnits_label_en-US" xlink:label="lab_srt_SECScheduleIIIRealEstateNumberOfUnits" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Number of Units</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SECScheduleIIIRealEstateNumberOfUnits" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_SECScheduleIIIRealEstateNumberOfUnits"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_SECScheduleIIIRealEstateNumberOfUnits" xlink:to="lab_srt_SECScheduleIIIRealEstateNumberOfUnits" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A1760BusinessCenterDriveRestonVAMember_019dbc7a-b287-79ac-b8b3-0fc903bf3908_terseLabel_en-US" xlink:label="lab_opi_A1760BusinessCenterDriveRestonVAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">1760 Business Center Drive, Reston, VA</link:label>
    <link:label id="lab_opi_A1760BusinessCenterDriveRestonVAMember_label_en-US" xlink:label="lab_opi_A1760BusinessCenterDriveRestonVAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">1760 Business Center Drive, Reston, VA [Member]</link:label>
    <link:label id="lab_opi_A1760BusinessCenterDriveRestonVAMember_documentation_en-US" xlink:label="lab_opi_A1760BusinessCenterDriveRestonVAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">1760 Business Center Drive, Reston, VA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A1760BusinessCenterDriveRestonVAMember" xlink:href="opi-20251231.xsd#opi_A1760BusinessCenterDriveRestonVAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A1760BusinessCenterDriveRestonVAMember" xlink:to="lab_opi_A1760BusinessCenterDriveRestonVAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_BaysideTechnologyParkFremontCAMember_019dbc7a-b1cb-7da5-a57b-dd7c2025673d_terseLabel_en-US" xlink:label="lab_opi_BaysideTechnologyParkFremontCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Bayside Technology Park, Fremont, CA</link:label>
    <link:label id="lab_opi_BaysideTechnologyParkFremontCAMember_label_en-US" xlink:label="lab_opi_BaysideTechnologyParkFremontCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Bayside Technology Park, Fremont, CA [Member]</link:label>
    <link:label id="lab_opi_BaysideTechnologyParkFremontCAMember_documentation_en-US" xlink:label="lab_opi_BaysideTechnologyParkFremontCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Bayside Technology Park, Fremont, CA [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_BaysideTechnologyParkFremontCAMember" xlink:href="opi-20251231.xsd#opi_BaysideTechnologyParkFremontCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_BaysideTechnologyParkFremontCAMember" xlink:to="lab_opi_BaysideTechnologyParkFremontCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_NoncashFinancingItemsAbstract_019dbc7a-b286-73d4-9d54-0b1831bb24ef_terseLabel_en-US" xlink:label="lab_opi_NoncashFinancingItemsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">NON-CASH FINANCING ACTIVITIES:</link:label>
    <link:label id="lab_opi_NoncashFinancingItemsAbstract_label_en-US" xlink:label="lab_opi_NoncashFinancingItemsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Noncash Financing Items [Abstract]</link:label>
    <link:label id="lab_opi_NoncashFinancingItemsAbstract_documentation_en-US" xlink:label="lab_opi_NoncashFinancingItemsAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Noncash Financing Items</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_NoncashFinancingItemsAbstract" xlink:href="opi-20251231.xsd#opi_NoncashFinancingItemsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_NoncashFinancingItemsAbstract" xlink:to="lab_opi_NoncashFinancingItemsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfRealEstateInvestments_019dbc7a-b287-753e-aa77-3b391a8c8a8f_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfRealEstateInvestments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Threshold amount of real estate investments</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfRealEstateInvestments_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfRealEstateInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction Base Management Fee Payable Threshold Amount of Real Estate Investments</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfRealEstateInvestments_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfRealEstateInvestments" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the threshold amount of real estate investments for payment of base management fee.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfRealEstateInvestments" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfRealEstateInvestments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfRealEstateInvestments" xlink:to="lab_opi_RelatedPartyTransactionBaseManagementFeePayableThresholdAmountOfRealEstateInvestments" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_AuditorName_019dbc7a-b1cb-75bf-b3be-6a5f88328a06_terseLabel_en-US" xlink:label="lab_dei_AuditorName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Auditor Name</link:label>
    <link:label id="lab_dei_AuditorName_label_en-US" xlink:label="lab_dei_AuditorName" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Auditor Name</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AuditorName" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_AuditorName"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_AuditorName" xlink:to="lab_dei_AuditorName" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_PropertyManagementAgreementPropertyManagementFeesMember_019dbc7a-b287-7d46-8b32-29b3e598b7f2_terseLabel_en-US" xlink:label="lab_opi_PropertyManagementAgreementPropertyManagementFeesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property management fees</link:label>
    <link:label id="lab_opi_PropertyManagementAgreementPropertyManagementFeesMember_label_en-US" xlink:label="lab_opi_PropertyManagementAgreementPropertyManagementFeesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property Management Agreement, Property Management Fees [Member]</link:label>
    <link:label id="lab_opi_PropertyManagementAgreementPropertyManagementFeesMember_documentation_en-US" xlink:label="lab_opi_PropertyManagementAgreementPropertyManagementFeesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Property Management Agreement, Property Management Fees</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_PropertyManagementAgreementPropertyManagementFeesMember" xlink:href="opi-20251231.xsd#opi_PropertyManagementAgreementPropertyManagementFeesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_PropertyManagementAgreementPropertyManagementFeesMember" xlink:to="lab_opi_PropertyManagementAgreementPropertyManagementFeesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LongTermDebtReorganizedCommonStockAndWarrantsProRataPercentageReceivable_019dff25-d44f-7e12-877a-f7029f88ba69_terseLabel_en-US" xlink:label="lab_opi_LongTermDebtReorganizedCommonStockAndWarrantsProRataPercentageReceivable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pro rata percentage of equity and warrants receivable</link:label>
    <link:label id="lab_opi_LongTermDebtReorganizedCommonStockAndWarrantsProRataPercentageReceivable_label_en-US" xlink:label="lab_opi_LongTermDebtReorganizedCommonStockAndWarrantsProRataPercentageReceivable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Reorganized Common Stock And Warrants, Pro Rata Percentage Receivable</link:label>
    <link:label id="lab_opi_LongTermDebtReorganizedCommonStockAndWarrantsProRataPercentageReceivable_documentation_en-US" xlink:label="lab_opi_LongTermDebtReorganizedCommonStockAndWarrantsProRataPercentageReceivable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Reorganized Common Stock And Warrants, Pro Rata Percentage Receivable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LongTermDebtReorganizedCommonStockAndWarrantsProRataPercentageReceivable" xlink:href="opi-20251231.xsd#opi_LongTermDebtReorganizedCommonStockAndWarrantsProRataPercentageReceivable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LongTermDebtReorganizedCommonStockAndWarrantsProRataPercentageReceivable" xlink:to="lab_opi_LongTermDebtReorganizedCommonStockAndWarrantsProRataPercentageReceivable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ConcentrationRiskTable_019dbc7a-b287-787e-ab2d-4f601f7345a9_terseLabel_en-US" xlink:label="lab_us-gaap_ConcentrationRiskTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Concentration Risk [Table]</link:label>
    <link:label id="lab_us-gaap_ConcentrationRiskTable_label_en-US" xlink:label="lab_us-gaap_ConcentrationRiskTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConcentrationRiskTable" xlink:to="lab_us-gaap_ConcentrationRiskTable" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_BankruptcyPolicyPolicyTextBlock_019dd0b2-6044-7bc8-9755-7a726fe5fc7b_terseLabel_en-US" xlink:label="lab_opi_BankruptcyPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Financial Reporting during Bankruptcy Proceedings</link:label>
    <link:label id="lab_opi_BankruptcyPolicyPolicyTextBlock_label_en-US" xlink:label="lab_opi_BankruptcyPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Bankruptcy, Policy [Policy Text Block]</link:label>
    <link:label id="lab_opi_BankruptcyPolicyPolicyTextBlock_documentation_en-US" xlink:label="lab_opi_BankruptcyPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Bankruptcy, Policy</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_BankruptcyPolicyPolicyTextBlock" xlink:href="opi-20251231.xsd#opi_BankruptcyPolicyPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_BankruptcyPolicyPolicyTextBlock" xlink:to="lab_opi_BankruptcyPolicyPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SupplementalCashFlowInformationAbstract_019dbc7a-b287-7c20-898b-7e14ec4011f9_terseLabel_en-US" xlink:label="lab_us-gaap_SupplementalCashFlowInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">SUPPLEMENTAL CASH FLOW INFORMATION:</link:label>
    <link:label id="lab_us-gaap_SupplementalCashFlowInformationAbstract_label_en-US" xlink:label="lab_us-gaap_SupplementalCashFlowInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Supplemental Cash Flow Information [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SupplementalCashFlowInformationAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract" xlink:to="lab_us-gaap_SupplementalCashFlowInformationAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEight_019dbc7a-b1cb-796a-9c2c-1b9b1facfc37_terseLabel_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEight" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2034</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEight_label_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEight" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right Exercisable In Year Eight</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEight_documentation_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEight" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right Exercisable In Year Eight</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEight" xlink:href="opi-20251231.xsd#opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEight"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEight" xlink:to="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearEight" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_OtherPerfMeasureAmt_terseLabel_en-US" xlink:label="lab_ecd_OtherPerfMeasureAmt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other Performance Measure, Amount</link:label>
    <link:label id="lab_ecd_OtherPerfMeasureAmt_label_en-US" xlink:label="lab_ecd_OtherPerfMeasureAmt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Performance Measure, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_OtherPerfMeasureAmt" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_OtherPerfMeasureAmt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_OtherPerfMeasureAmt" xlink:to="lab_ecd_OtherPerfMeasureAmt" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsOfDebtIssuanceCosts_019dbc8d-46f2-7c84-b1ed-b2ee72f50657_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsOfDebtIssuanceCosts" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Payment of debt issuance costs</link:label>
    <link:label id="lab_us-gaap_PaymentsOfDebtIssuanceCosts_label_en-US" xlink:label="lab_us-gaap_PaymentsOfDebtIssuanceCosts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments of Debt Issuance Costs</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDebtIssuanceCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsOfDebtIssuanceCosts"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsOfDebtIssuanceCosts" xlink:to="lab_us-gaap_PaymentsOfDebtIssuanceCosts" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RealEstateFederalIncomeTaxBasis_019dbc7a-b30c-77d7-924d-f3ae1bb7ee18_terseLabel_en-US" xlink:label="lab_srt_RealEstateFederalIncomeTaxBasis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate cost for federal income tax purposes</link:label>
    <link:label id="lab_srt_RealEstateFederalIncomeTaxBasis_label_en-US" xlink:label="lab_srt_RealEstateFederalIncomeTaxBasis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Federal Income Tax Basis</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateFederalIncomeTaxBasis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RealEstateFederalIncomeTaxBasis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RealEstateFederalIncomeTaxBasis" xlink:to="lab_srt_RealEstateFederalIncomeTaxBasis" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_NumberOfTrustees_019dbc7a-b286-790f-ad84-70f81265b162_terseLabel_en-US" xlink:label="lab_opi_NumberOfTrustees" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of trustees</link:label>
    <link:label id="lab_opi_NumberOfTrustees_label_en-US" xlink:label="lab_opi_NumberOfTrustees" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number Of Trustees</link:label>
    <link:label id="lab_opi_NumberOfTrustees_documentation_en-US" xlink:label="lab_opi_NumberOfTrustees" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Number Of Trustees</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_NumberOfTrustees" xlink:href="opi-20251231.xsd#opi_NumberOfTrustees"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_NumberOfTrustees" xlink:to="lab_opi_NumberOfTrustees" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths_019dbc7a-b1cb-7497-873b-a186f4562ebb_terseLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2026</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received, Year One</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths" xlink:to="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RelatedPartyDomain_019dbc7a-b1cb-7fc7-8075-656e648d9d5f_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Related Party [Domain]</link:label>
    <link:label id="lab_us-gaap_RelatedPartyDomain_label_en-US" xlink:label="lab_us-gaap_RelatedPartyDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related and Nonrelated Parties [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyDomain" xlink:to="lab_us-gaap_RelatedPartyDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_TransitionServiceMember_019dbc7a-b286-7245-96c3-fd423bda3089_terseLabel_en-US" xlink:label="lab_opi_TransitionServiceMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Transition Services</link:label>
    <link:label id="lab_opi_TransitionServiceMember_label_en-US" xlink:label="lab_opi_TransitionServiceMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Transition Service [Member]</link:label>
    <link:label id="lab_opi_TransitionServiceMember_documentation_en-US" xlink:label="lab_opi_TransitionServiceMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Transition Service [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_TransitionServiceMember" xlink:href="opi-20251231.xsd#opi_TransitionServiceMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_TransitionServiceMember" xlink:to="lab_opi_TransitionServiceMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_UnisonElliottBayLabSpaceSeattleWAMember_019dbc7a-b1cb-7b8c-bd26-057ee2357b6d_terseLabel_en-US" xlink:label="lab_opi_UnisonElliottBayLabSpaceSeattleWAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unison Elliott Bay-Lab Space, Seattle, WA</link:label>
    <link:label id="lab_opi_UnisonElliottBayLabSpaceSeattleWAMember_label_en-US" xlink:label="lab_opi_UnisonElliottBayLabSpaceSeattleWAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Unison Elliott Bay-Lab Space, Seattle, WA [Member]</link:label>
    <link:label id="lab_opi_UnisonElliottBayLabSpaceSeattleWAMember_documentation_en-US" xlink:label="lab_opi_UnisonElliottBayLabSpaceSeattleWAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Unison Elliott Bay-Lab Space, Seattle, WA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_UnisonElliottBayLabSpaceSeattleWAMember" xlink:href="opi-20251231.xsd#opi_UnisonElliottBayLabSpaceSeattleWAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_UnisonElliottBayLabSpaceSeattleWAMember" xlink:to="lab_opi_UnisonElliottBayLabSpaceSeattleWAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A2231SchrockRoadColumbusOHMember_019dbc7a-b1cb-79fc-9abe-346bbbf98c3c_terseLabel_en-US" xlink:label="lab_opi_A2231SchrockRoadColumbusOHMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2231 Schrock Road, Columbus, OH</link:label>
    <link:label id="lab_opi_A2231SchrockRoadColumbusOHMember_label_en-US" xlink:label="lab_opi_A2231SchrockRoadColumbusOHMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2231 Schrock Road, Columbus, OH [Member]</link:label>
    <link:label id="lab_opi_A2231SchrockRoadColumbusOHMember_documentation_en-US" xlink:label="lab_opi_A2231SchrockRoadColumbusOHMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2231 Schrock Road, Columbus, OH [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A2231SchrockRoadColumbusOHMember" xlink:href="opi-20251231.xsd#opi_A2231SchrockRoadColumbusOHMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A2231SchrockRoadColumbusOHMember" xlink:to="lab_opi_A2231SchrockRoadColumbusOHMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_VestingAxis_019dbc7a-b287-7b19-8f5b-41e1bf443ae0_terseLabel_en-US" xlink:label="lab_us-gaap_VestingAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vesting [Axis]</link:label>
    <link:label id="lab_us-gaap_VestingAxis_label_en-US" xlink:label="lab_us-gaap_VestingAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Vesting [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VestingAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VestingAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_VestingAxis" xlink:to="lab_us-gaap_VestingAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RestrictedCash_019dbc8e-5327-7d09-9df6-a4f112bd5522_terseLabel_en-US" xlink:label="lab_us-gaap_RestrictedCash" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Restricted cash</link:label>
    <link:label id="lab_us-gaap_RestrictedCash_label_en-US" xlink:label="lab_us-gaap_RestrictedCash" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Restricted Cash</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCash" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedCash"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RestrictedCash" xlink:to="lab_us-gaap_RestrictedCash" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AdditionalPaidInCapitalCommonStock_019dbc7a-b286-77d1-b404-b28bf60ddfe5_terseLabel_en-US" xlink:label="lab_us-gaap_AdditionalPaidInCapitalCommonStock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Additional paid in capital</link:label>
    <link:label id="lab_us-gaap_AdditionalPaidInCapitalCommonStock_label_en-US" xlink:label="lab_us-gaap_AdditionalPaidInCapitalCommonStock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Additional Paid in Capital, Common Stock</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdditionalPaidInCapitalCommonStock" xlink:to="lab_us-gaap_AdditionalPaidInCapitalCommonStock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_019dbc7a-b286-7c21-b1e4-c1ef2597167e_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash provided by investing activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Provided by (Used in) Investing Activity, Including Discontinued Operation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RealEstateAndAccumulatedDepreciationEquipmentLifeUsedForDepreciation_019dbc7a-b30c-7962-b0a1-d6e96f3af999_terseLabel_en-US" xlink:label="lab_opi_RealEstateAndAccumulatedDepreciationEquipmentLifeUsedForDepreciation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Useful life of equipment</link:label>
    <link:label id="lab_opi_RealEstateAndAccumulatedDepreciationEquipmentLifeUsedForDepreciation_label_en-US" xlink:label="lab_opi_RealEstateAndAccumulatedDepreciationEquipmentLifeUsedForDepreciation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate and Accumulated Depreciation Equipment Life Used for Depreciation</link:label>
    <link:label id="lab_opi_RealEstateAndAccumulatedDepreciationEquipmentLifeUsedForDepreciation_documentation_en-US" xlink:label="lab_opi_RealEstateAndAccumulatedDepreciationEquipmentLifeUsedForDepreciation" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the estimated economic life of equipment on which depreciation in the latest income statement was computed.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RealEstateAndAccumulatedDepreciationEquipmentLifeUsedForDepreciation" xlink:href="opi-20251231.xsd#opi_RealEstateAndAccumulatedDepreciationEquipmentLifeUsedForDepreciation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RealEstateAndAccumulatedDepreciationEquipmentLifeUsedForDepreciation" xlink:to="lab_opi_RealEstateAndAccumulatedDepreciationEquipmentLifeUsedForDepreciation" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AggtChngPnsnValInSummryCompstnTblForAplblYrMember_terseLabel_en-US" xlink:label="lab_ecd_AggtChngPnsnValInSummryCompstnTblForAplblYrMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table</link:label>
    <link:label id="lab_ecd_AggtChngPnsnValInSummryCompstnTblForAplblYrMember_label_en-US" xlink:label="lab_ecd_AggtChngPnsnValInSummryCompstnTblForAplblYrMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AggtChngPnsnValInSummryCompstnTblForAplblYrMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AggtChngPnsnValInSummryCompstnTblForAplblYrMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AggtChngPnsnValInSummryCompstnTblForAplblYrMember" xlink:to="lab_ecd_AggtChngPnsnValInSummryCompstnTblForAplblYrMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_CumulativeCommonDistributionsMember_019dbc7a-b286-7bbb-8b4c-b5b070d09ac3_terseLabel_en-US" xlink:label="lab_opi_CumulativeCommonDistributionsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cumulative Common Distributions</link:label>
    <link:label id="lab_opi_CumulativeCommonDistributionsMember_label_en-US" xlink:label="lab_opi_CumulativeCommonDistributionsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cumulative Common Distributions [Member]</link:label>
    <link:label id="lab_opi_CumulativeCommonDistributionsMember_documentation_en-US" xlink:label="lab_opi_CumulativeCommonDistributionsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents cumulative distributions to common shareholders.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_CumulativeCommonDistributionsMember" xlink:href="opi-20251231.xsd#opi_CumulativeCommonDistributionsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_CumulativeCommonDistributionsMember" xlink:to="lab_opi_CumulativeCommonDistributionsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InterestPaidNet_019dbc8e-357c-767f-96b9-10c79b00b21e_terseLabel_en-US" xlink:label="lab_us-gaap_InterestPaidNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest paid</link:label>
    <link:label id="lab_us-gaap_InterestPaidNet_label_en-US" xlink:label="lab_us-gaap_InterestPaidNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Paid, Excluding Capitalized Interest, Operating Activity</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPaidNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestPaidNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestPaidNet" xlink:to="lab_us-gaap_InterestPaidNet" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentFiscalYearFocus_019dbc7a-b1cb-7d87-bc97-9175d6ece9f3_terseLabel_en-US" xlink:label="lab_dei_DocumentFiscalYearFocus" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Document Fiscal Year Focus</link:label>
    <link:label id="lab_dei_DocumentFiscalYearFocus_label_en-US" xlink:label="lab_dei_DocumentFiscalYearFocus" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Document Fiscal Year Focus</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentFiscalYearFocus"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentFiscalYearFocus" xlink:to="lab_dei_DocumentFiscalYearFocus" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BasisOfAccountingPolicyPolicyTextBlock_019dbc7a-b286-762e-829b-ae66fa7f787f_terseLabel_en-US" xlink:label="lab_us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Basis of Presentation</link:label>
    <link:label id="lab_us-gaap_BasisOfAccountingPolicyPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Basis of Accounting, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BasisOfAccountingPolicyPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:to="lab_us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CarryingReportedAmountFairValueDisclosureMember_019dbc7a-b1cb-7a79-9ced-a55a4b41f8cd_terseLabel_en-US" xlink:label="lab_us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Carrying Amount</link:label>
    <link:label id="lab_us-gaap_CarryingReportedAmountFairValueDisclosureMember_label_en-US" xlink:label="lab_us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reported Value Measurement [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:to="lab_us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PlanNameDomain_019dbc7a-b1cb-7621-aa26-dde883568b78_terseLabel_en-US" xlink:label="lab_us-gaap_PlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Plan Name [Domain]</link:label>
    <link:label id="lab_us-gaap_PlanNameDomain_label_en-US" xlink:label="lab_us-gaap_PlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Plan Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PlanNameDomain" xlink:to="lab_us-gaap_PlanNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessCombinationAcquisitionRelatedCosts_019dbc7a-b287-7a64-812a-6ba6e4c9d78a_verboseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Transaction related costs</link:label>
    <link:label id="lab_us-gaap_BusinessCombinationAcquisitionRelatedCosts_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Acquisition-Related Cost, Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:to="lab_us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_019dbc7a-b287-7d9f-816a-fabbc17e8607_terseLabel_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted average period of recognition of compensation expenses (in years)</link:label>
    <link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_label_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:to="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAbstract_019dbc7a-b287-7605-858f-838e3c8605ab_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate [Abstract]</link:label>
    <link:label id="lab_us-gaap_RealEstateAbstract_label_en-US" xlink:label="lab_us-gaap_RealEstateAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAbstract" xlink:to="lab_us-gaap_RealEstateAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityAbstract_019dbc7a-b287-7a92-a802-10c40fd7fa72_terseLabel_en-US" xlink:label="lab_us-gaap_EquityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity [Abstract]</link:label>
    <link:label id="lab_us-gaap_EquityAbstract_label_en-US" xlink:label="lab_us-gaap_EquityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityAbstract" xlink:to="lab_us-gaap_EquityAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_TenThreeTwentyColumbiaMDMember_019dbc7a-b287-7b64-9fa4-51a1d80ad812_terseLabel_en-US" xlink:label="lab_opi_TenThreeTwentyColumbiaMDMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">TenThreeTwenty, Columbia, MD</link:label>
    <link:label id="lab_opi_TenThreeTwentyColumbiaMDMember_label_en-US" xlink:label="lab_opi_TenThreeTwentyColumbiaMDMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">TenThreeTwenty, Columbia, MD [Member]</link:label>
    <link:label id="lab_opi_TenThreeTwentyColumbiaMDMember_documentation_en-US" xlink:label="lab_opi_TenThreeTwentyColumbiaMDMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">TenThreeTwenty, Columbia, MD [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_TenThreeTwentyColumbiaMDMember" xlink:href="opi-20251231.xsd#opi_TenThreeTwentyColumbiaMDMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_TenThreeTwentyColumbiaMDMember" xlink:to="lab_opi_TenThreeTwentyColumbiaMDMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SeniorNotes_019dbc7a-b1cb-773b-aee9-be0f054a6ff0_netLabel_en-US" xlink:label="lab_us-gaap_SeniorNotes" xlink:role="http://www.xbrl.org/2009/role/netLabel" xlink:type="resource" xml:lang="en-US">Senior notes</link:label>
    <link:label id="lab_us-gaap_SeniorNotes_label_en-US" xlink:label="lab_us-gaap_SeniorNotes" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Senior Notes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotes" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SeniorNotes"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SeniorNotes" xlink:to="lab_us-gaap_SeniorNotes" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_TrancheBMember_019dd613-dd9e-7878-a589-c7e818703869_terseLabel_en-US" xlink:label="lab_opi_TrancheBMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tranche B</link:label>
    <link:label id="lab_opi_TrancheBMember_label_en-US" xlink:label="lab_opi_TrancheBMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tranche B [Member]</link:label>
    <link:label id="lab_opi_TrancheBMember_documentation_en-US" xlink:label="lab_opi_TrancheBMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tranche B</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_TrancheBMember" xlink:href="opi-20251231.xsd#opi_TrancheBMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_TrancheBMember" xlink:to="lab_opi_TrancheBMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SegmentReportingDisclosureTextBlock_019dbc7a-b286-7fc6-9802-4a398c7f1ca0_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentReportingDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Segment Reporting</link:label>
    <link:label id="lab_us-gaap_SegmentReportingDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_SegmentReportingDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentReportingDisclosureTextBlock" xlink:to="lab_us-gaap_SegmentReportingDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_TerminationFeeTerm_019dbc7a-b1cb-7bd3-9ccd-6da9e07e14a9_terseLabel_en-US" xlink:label="lab_opi_TerminationFeeTerm" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Termination fee term</link:label>
    <link:label id="lab_opi_TerminationFeeTerm_label_en-US" xlink:label="lab_opi_TerminationFeeTerm" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Termination Fee Term</link:label>
    <link:label id="lab_opi_TerminationFeeTerm_documentation_en-US" xlink:label="lab_opi_TerminationFeeTerm" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the term in years used to calculate the fee for termination of one or both of the company's amended management agreements for a performance reason.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_TerminationFeeTerm" xlink:href="opi-20251231.xsd#opi_TerminationFeeTerm"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_TerminationFeeTerm" xlink:to="lab_opi_TerminationFeeTerm" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A12.000DebtorInPossessionTermLoanMember_019e1853-92e7-7977-9f15-65025a504afd_verboseLabel_en-US" xlink:label="lab_opi_A12.000DebtorInPossessionTermLoanMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">A&amp;R DIP Credit Agreement</link:label>
    <link:label id="lab_opi_A12.000DebtorInPossessionTermLoanMember_019dd0a9-a49a-7b34-8ac3-d1e5d1cf6544_terseLabel_en-US" xlink:label="lab_opi_A12.000DebtorInPossessionTermLoanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debtor-in-possession term loan, 12.000% interest rate, due in 2026</link:label>
    <link:label id="lab_opi_A12.000DebtorInPossessionTermLoanMember_label_en-US" xlink:label="lab_opi_A12.000DebtorInPossessionTermLoanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">12.000% Debtor-In-Possession Term Loan [Member]</link:label>
    <link:label id="lab_opi_A12.000DebtorInPossessionTermLoanMember_documentation_en-US" xlink:label="lab_opi_A12.000DebtorInPossessionTermLoanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">12.000% Debtor-In-Possession Term Loan</link:label>
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    <link:label id="lab_opi_RelatedPartyTransactionRenewalTerm_019dbc7a-b287-7959-a33c-616da4030618_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionRenewalTerm" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Renewal term</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionRenewalTerm_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionRenewalTerm" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Renewal Term</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionRenewalTerm_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionRenewalTerm" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Renewal Term</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionRenewalTerm" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionRenewalTerm"/>
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    <link:label id="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019dbc7a-b1cb-7943-a3fb-e4265e68ea9b_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Shareholders' Equity</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Stockholders' Equity [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
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    <link:label id="lab_opi_BusinessManagementAgreementMember_019dbc7a-b286-79c5-9b0c-791afc419f51_terseLabel_en-US" xlink:label="lab_opi_BusinessManagementAgreementMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Business management agreement</link:label>
    <link:label id="lab_opi_BusinessManagementAgreementMember_label_en-US" xlink:label="lab_opi_BusinessManagementAgreementMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Management Agreement [Member]</link:label>
    <link:label id="lab_opi_BusinessManagementAgreementMember_documentation_en-US" xlink:label="lab_opi_BusinessManagementAgreementMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Business Management Agreement</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_BusinessManagementAgreementMember" xlink:href="opi-20251231.xsd#opi_BusinessManagementAgreementMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_BusinessManagementAgreementMember" xlink:to="lab_opi_BusinessManagementAgreementMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSeven_019dbc7a-b1cb-7c6e-bdc5-a3e501f8b6ba_terseLabel_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSeven" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2032</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSeven_label_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSeven" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right, Exercisable In Year Seven</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSeven_documentation_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSeven" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right, Exercisable In Year Seven</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSeven" xlink:href="opi-20251231.xsd#opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSeven"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSeven" xlink:to="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearSeven" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_CompActuallyPaidVsTotalShareholderRtnTextBlock_terseLabel_en-US" xlink:label="lab_ecd_CompActuallyPaidVsTotalShareholderRtnTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Compensation Actually Paid vs. Total Shareholder Return</link:label>
    <link:label id="lab_ecd_CompActuallyPaidVsTotalShareholderRtnTextBlock_label_en-US" xlink:label="lab_ecd_CompActuallyPaidVsTotalShareholderRtnTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Compensation Actually Paid vs. Total Shareholder Return [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_CompActuallyPaidVsTotalShareholderRtnTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_CompActuallyPaidVsTotalShareholderRtnTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_CompActuallyPaidVsTotalShareholderRtnTextBlock" xlink:to="lab_ecd_CompActuallyPaidVsTotalShareholderRtnTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_WeightedAverageMember_019dbc7a-b286-7dea-a382-66d88353da06_terseLabel_en-US" xlink:label="lab_srt_WeightedAverageMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted Average</link:label>
    <link:label id="lab_srt_WeightedAverageMember_label_en-US" xlink:label="lab_srt_WeightedAverageMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Weighted Average [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_WeightedAverageMember" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_WeightedAverageMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_WeightedAverageMember" xlink:to="lab_srt_WeightedAverageMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AmortizationOfIntangibleAssets_019dbc85-feda-7e23-8213-542afdaa0d34_terseLabel_en-US" xlink:label="lab_us-gaap_AmortizationOfIntangibleAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amortization of acquired real estate leases and assumed real estate lease obligations, net</link:label>
    <link:label id="lab_us-gaap_AmortizationOfIntangibleAssets_019dbc7a-b286-707d-b9ed-1063ebcb8cb7_verboseLabel_en-US" xlink:label="lab_us-gaap_AmortizationOfIntangibleAssets" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Amortization of the value of leases</link:label>
    <link:label id="lab_us-gaap_AmortizationOfIntangibleAssets_label_en-US" xlink:label="lab_us-gaap_AmortizationOfIntangibleAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amortization of Intangible Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AmortizationOfIntangibleAssets" xlink:to="lab_us-gaap_AmortizationOfIntangibleAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ExtinguishmentOfDebtInExchangeForSeniorNotesAndCommonShares_019dbc8e-4d30-7f2f-8aae-8c01af061eed_negatedTerseLabel_en-US" xlink:label="lab_opi_ExtinguishmentOfDebtInExchangeForSeniorNotesAndCommonShares" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Extinguishment of unsecured senior notes in exchange for senior secured notes and common shares</link:label>
    <link:label id="lab_opi_ExtinguishmentOfDebtInExchangeForSeniorNotesAndCommonShares_label_en-US" xlink:label="lab_opi_ExtinguishmentOfDebtInExchangeForSeniorNotesAndCommonShares" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Extinguishment Of Debt In Exchange For Senior Notes And Common Shares</link:label>
    <link:label id="lab_opi_ExtinguishmentOfDebtInExchangeForSeniorNotesAndCommonShares_documentation_en-US" xlink:label="lab_opi_ExtinguishmentOfDebtInExchangeForSeniorNotesAndCommonShares" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Extinguishment Of Debt In Exchange For Senior Notes And Common Shares</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ExtinguishmentOfDebtInExchangeForSeniorNotesAndCommonShares" xlink:href="opi-20251231.xsd#opi_ExtinguishmentOfDebtInExchangeForSeniorNotesAndCommonShares"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ExtinguishmentOfDebtInExchangeForSeniorNotesAndCommonShares" xlink:to="lab_opi_ExtinguishmentOfDebtInExchangeForSeniorNotesAndCommonShares" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionPercentageOfReorganizedCommonEquityPayable_019dd5fe-6f48-73ae-898e-abc65f31aae6_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionPercentageOfReorganizedCommonEquityPayable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage of reorganized common equity payable under agreement</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionPercentageOfReorganizedCommonEquityPayable_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionPercentageOfReorganizedCommonEquityPayable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Percentage Of Reorganized Common Equity Payable</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionPercentageOfReorganizedCommonEquityPayable_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionPercentageOfReorganizedCommonEquityPayable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Percentage Of Reorganized Common Equity Payable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionPercentageOfReorganizedCommonEquityPayable" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionPercentageOfReorganizedCommonEquityPayable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionPercentageOfReorganizedCommonEquityPayable" xlink:to="lab_opi_RelatedPartyTransactionPercentageOfReorganizedCommonEquityPayable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SaleOfStockConsiderationReceivedOnTransaction_019dd0dc-686b-7fcd-8bb8-6d3c7203852a_terseLabel_en-US" xlink:label="lab_us-gaap_SaleOfStockConsiderationReceivedOnTransaction" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from sale of stock</link:label>
    <link:label id="lab_us-gaap_SaleOfStockConsiderationReceivedOnTransaction_label_en-US" xlink:label="lab_us-gaap_SaleOfStockConsiderationReceivedOnTransaction" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale of Stock, Consideration Received on Transaction</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockConsiderationReceivedOnTransaction" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SaleOfStockConsiderationReceivedOnTransaction"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SaleOfStockConsiderationReceivedOnTransaction" xlink:to="lab_us-gaap_SaleOfStockConsiderationReceivedOnTransaction" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtorReorganizationItemsLegalAndAdvisoryProfessionalFees_019dd0bf-9a17-7053-b338-f9a5aa32f6cf_terseLabel_en-US" xlink:label="lab_us-gaap_DebtorReorganizationItemsLegalAndAdvisoryProfessionalFees" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Professional fees</link:label>
    <link:label id="lab_us-gaap_DebtorReorganizationItemsLegalAndAdvisoryProfessionalFees_label_en-US" xlink:label="lab_us-gaap_DebtorReorganizationItemsLegalAndAdvisoryProfessionalFees" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debtor Reorganization Items, Legal and Advisory Professional Fees</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtorReorganizationItemsLegalAndAdvisoryProfessionalFees" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtorReorganizationItemsLegalAndAdvisoryProfessionalFees"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtorReorganizationItemsLegalAndAdvisoryProfessionalFees" xlink:to="lab_us-gaap_DebtorReorganizationItemsLegalAndAdvisoryProfessionalFees" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearOne_019dbc7a-b286-7c15-9522-c872e71623b9_terseLabel_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearOne" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2025</link:label>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearOne_label_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearOne" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Finance Costs, Future Amortization Expense Year One</link:label>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearOne_documentation_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearOne" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of amortization of deferred financing fees expected to be recognized during year one of the five succeeding fiscal years.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DeferredFinanceCostsFutureAmortizationExpenseYearOne" xlink:href="opi-20251231.xsd#opi_DeferredFinanceCostsFutureAmortizationExpenseYearOne"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DeferredFinanceCostsFutureAmortizationExpenseYearOne" xlink:to="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearOne" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RevolvingCreditFacilityMember_019dbc7a-b287-73df-a6da-4e37b9f218f4_terseLabel_en-US" xlink:label="lab_us-gaap_RevolvingCreditFacilityMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revolving credit facility</link:label>
    <link:label id="lab_us-gaap_RevolvingCreditFacilityMember_label_en-US" xlink:label="lab_us-gaap_RevolvingCreditFacilityMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revolving Credit Facility [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevolvingCreditFacilityMember" xlink:to="lab_us-gaap_RevolvingCreditFacilityMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A2900WestPlanoParkwayPlanoTXMember_019dbc7a-b1cb-7e79-96e9-9ea7c94a1a03_terseLabel_en-US" xlink:label="lab_opi_A2900WestPlanoParkwayPlanoTXMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2900 West Plano Parkway, Plano, TX</link:label>
    <link:label id="lab_opi_A2900WestPlanoParkwayPlanoTXMember_label_en-US" xlink:label="lab_opi_A2900WestPlanoParkwayPlanoTXMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2900 West Plano Parkway, Plano, TX [Member]</link:label>
    <link:label id="lab_opi_A2900WestPlanoParkwayPlanoTXMember_documentation_en-US" xlink:label="lab_opi_A2900WestPlanoParkwayPlanoTXMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2900 West Plano Parkway, Plano, TX [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A2900WestPlanoParkwayPlanoTXMember" xlink:href="opi-20251231.xsd#opi_A2900WestPlanoParkwayPlanoTXMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A2900WestPlanoParkwayPlanoTXMember" xlink:to="lab_opi_A2900WestPlanoParkwayPlanoTXMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_AuditorInformationAbstract_label_en-US" xlink:label="lab_opi_AuditorInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Auditor Information [Abstract]</link:label>
    <link:label id="lab_opi_AuditorInformationAbstract_documentation_en-US" xlink:label="lab_opi_AuditorInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Auditor Information</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_AuditorInformationAbstract" xlink:href="opi-20251231.xsd#opi_AuditorInformationAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_AuditorInformationAbstract" xlink:to="lab_opi_AuditorInformationAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_TrdArrDuration_terseLabel_en-US" xlink:label="lab_ecd_TrdArrDuration" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Arrangement Duration</link:label>
    <link:label id="lab_ecd_TrdArrDuration_label_en-US" xlink:label="lab_ecd_TrdArrDuration" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Trading Arrangement Duration</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_TrdArrDuration" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_TrdArrDuration"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_TrdArrDuration" xlink:to="lab_ecd_TrdArrDuration" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredSalesInducementsAmortizationExpense_019dbc7a-b1cb-7f2b-b18e-51a4cde048d6_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredSalesInducementsAmortizationExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred sales inducement cost, amortization expense</link:label>
    <link:label id="lab_us-gaap_DeferredSalesInducementsAmortizationExpense_label_en-US" xlink:label="lab_us-gaap_DeferredSalesInducementsAmortizationExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Sales Inducement Cost, Amortization Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredSalesInducementsAmortizationExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredSalesInducementsAmortizationExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredSalesInducementsAmortizationExpense" xlink:to="lab_us-gaap_DeferredSalesInducementsAmortizationExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_LocalPhoneNumber_019dbc7a-b287-7492-8666-8e1a818515df_terseLabel_en-US" xlink:label="lab_dei_LocalPhoneNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Local Phone Number</link:label>
    <link:label id="lab_dei_LocalPhoneNumber_label_en-US" xlink:label="lab_dei_LocalPhoneNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Local Phone Number</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LocalPhoneNumber"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_LocalPhoneNumber" xlink:to="lab_dei_LocalPhoneNumber" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_Additional402vDisclosureTextBlock_terseLabel_en-US" xlink:label="lab_ecd_Additional402vDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Additional 402(v) Disclosure</link:label>
    <link:label id="lab_ecd_Additional402vDisclosureTextBlock_label_en-US" xlink:label="lab_ecd_Additional402vDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Additional 402(v) Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_Additional402vDisclosureTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_Additional402vDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_Additional402vDisclosureTextBlock" xlink:to="lab_ecd_Additional402vDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_019dbc7a-b286-7385-b9cf-d079a7e35201_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Thereafter</link:label>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Maturity, after Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_019dbc7a-b30c-7f60-bcd3-4003fb95d3c3_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Common stock repurchases (in shares)</link:label>
    <link:label id="lab_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_label_en-US" xlink:label="lab_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Repurchased and Retired During Period, Shares</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:to="lab_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OffMarketLeaseUnfavorable_019dbc7a-b287-78a9-a445-494b8d42ea7f_terseLabel_en-US" xlink:label="lab_us-gaap_OffMarketLeaseUnfavorable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assumed real estate lease obligations, net</link:label>
    <link:label id="lab_us-gaap_OffMarketLeaseUnfavorable_019dbc7a-b287-7401-a9c3-5890dfe24503_totalLabel_en-US" xlink:label="lab_us-gaap_OffMarketLeaseUnfavorable" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Assumed real estate lease obligations, net</link:label>
    <link:label id="lab_us-gaap_OffMarketLeaseUnfavorable_label_en-US" xlink:label="lab_us-gaap_OffMarketLeaseUnfavorable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Off-Market Lease, Unfavorable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OffMarketLeaseUnfavorable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OffMarketLeaseUnfavorable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OffMarketLeaseUnfavorable" xlink:to="lab_us-gaap_OffMarketLeaseUnfavorable" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFive_019dbc7a-b1cb-70bf-9470-5a9b863e56e4_terseLabel_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2030</link:label>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFive_label_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Costs, Leasing Future Amortization Expense Year Five</link:label>
    <link:label id="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFive_documentation_en-US" xlink:label="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFive" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of amortization of deferred leasing costs expected to be recognized during year five of the five succeeding fiscal years.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFive" xlink:href="opi-20251231.xsd#opi_DeferredCostsLeasingFutureAmortizationExpenseYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFive" xlink:to="lab_opi_DeferredCostsLeasingFutureAmortizationExpenseYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_FourteenGovernmentTenantsMember_019dbc7a-b1cb-7cb8-a0c4-5b7853927caa_terseLabel_en-US" xlink:label="lab_opi_FourteenGovernmentTenantsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fourteen Government Tenants</link:label>
    <link:label id="lab_opi_FourteenGovernmentTenantsMember_label_en-US" xlink:label="lab_opi_FourteenGovernmentTenantsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fourteen Government Tenants [Member]</link:label>
    <link:label id="lab_opi_FourteenGovernmentTenantsMember_documentation_en-US" xlink:label="lab_opi_FourteenGovernmentTenantsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fourteen Government Tenants [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_FourteenGovernmentTenantsMember" xlink:href="opi-20251231.xsd#opi_FourteenGovernmentTenantsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_FourteenGovernmentTenantsMember" xlink:to="lab_opi_FourteenGovernmentTenantsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A10350NW112thAvenueMiamiFLMember_019dbc7a-b1cb-7ae4-a753-ef1608f75328_terseLabel_en-US" xlink:label="lab_opi_A10350NW112thAvenueMiamiFLMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">10350 NW 112th Avenue, Miami, FL</link:label>
    <link:label id="lab_opi_A10350NW112thAvenueMiamiFLMember_label_en-US" xlink:label="lab_opi_A10350NW112thAvenueMiamiFLMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">10350 NW 112th Avenue, Miami, FL [Member]</link:label>
    <link:label id="lab_opi_A10350NW112thAvenueMiamiFLMember_documentation_en-US" xlink:label="lab_opi_A10350NW112thAvenueMiamiFLMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">10350 NW 112th Avenue, Miami, FL [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A10350NW112thAvenueMiamiFLMember" xlink:href="opi-20251231.xsd#opi_A10350NW112thAvenueMiamiFLMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A10350NW112thAvenueMiamiFLMember" xlink:to="lab_opi_A10350NW112thAvenueMiamiFLMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AssetsAbstract_019dbc7a-b286-7810-890d-0e4ca8c467c5_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">ASSETS</link:label>
    <link:label id="lab_us-gaap_AssetsAbstract_label_en-US" xlink:label="lab_us-gaap_AssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="lab_us-gaap_AssetsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CreditFacilityAxis_019dbc7a-b287-7e04-bdda-6d9d28aa6e74_terseLabel_en-US" xlink:label="lab_us-gaap_CreditFacilityAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Credit Facility [Axis]</link:label>
    <link:label id="lab_us-gaap_CreditFacilityAxis_label_en-US" xlink:label="lab_us-gaap_CreditFacilityAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Credit Facility [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CreditFacilityAxis" xlink:to="lab_us-gaap_CreditFacilityAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_UndrlygSecurityMktPriceChngPct_terseLabel_en-US" xlink:label="lab_ecd_UndrlygSecurityMktPriceChngPct" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Underlying Security Market Price Change</link:label>
    <link:label id="lab_ecd_UndrlygSecurityMktPriceChngPct_label_en-US" xlink:label="lab_ecd_UndrlygSecurityMktPriceChngPct" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Underlying Security Market Price Change, Percent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_UndrlygSecurityMktPriceChngPct" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_UndrlygSecurityMktPriceChngPct"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_UndrlygSecurityMktPriceChngPct" xlink:to="lab_ecd_UndrlygSecurityMktPriceChngPct" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentAxis_019dbc7a-b287-7676-af4c-221d6a12aca9_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Instrument [Axis]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentAxis_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentAxis" xlink:to="lab_us-gaap_DebtInstrumentAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_019dbc7a-b1cb-74cc-9232-e93210dc37ed_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Forfeited (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueDisclosuresTextBlock_019dbc7a-b287-7380-b9de-35186dbb34a0_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueDisclosuresTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair Value of Assets and Liabilities</link:label>
    <link:label id="lab_us-gaap_FairValueDisclosuresTextBlock_label_en-US" xlink:label="lab_us-gaap_FairValueDisclosuresTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value Disclosures [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueDisclosuresTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueDisclosuresTextBlock" xlink:to="lab_us-gaap_FairValueDisclosuresTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt_019dbc86-99f1-741d-8031-269b31a14ac4_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Net gain on early extinguishment of debt</link:label>
    <link:label id="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt_019dbc7a-b286-789a-a3e1-0875552a9073_terseLabel_en-US" xlink:label="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gain (loss) on early extinguishment of debt</link:label>
    <link:label id="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt_label_en-US" xlink:label="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gain (Loss) on Extinguishment of Debt</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:to="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CreditFacilityDomain_019dbc7a-b286-7118-b9cd-202d6b7a9906_terseLabel_en-US" xlink:label="lab_us-gaap_CreditFacilityDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Credit Facility [Domain]</link:label>
    <link:label id="lab_us-gaap_CreditFacilityDomain_label_en-US" xlink:label="lab_us-gaap_CreditFacilityDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Credit Facility [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CreditFacilityDomain" xlink:to="lab_us-gaap_CreditFacilityDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockholdersEquityAbstract_019dbc7a-b287-7776-80c5-e147ac7507ee_terseLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Shareholders&#8217; equity:</link:label>
    <link:label id="lab_us-gaap_StockholdersEquityAbstract_label_en-US" xlink:label="lab_us-gaap_StockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity, Attributable to Parent [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockholdersEquityAbstract" xlink:to="lab_us-gaap_StockholdersEquityAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InvestmentBuildingAndBuildingImprovements_019dbc7a-b1cb-745d-abe2-17bc442b7ed1_terseLabel_en-US" xlink:label="lab_us-gaap_InvestmentBuildingAndBuildingImprovements" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Buildings and improvements</link:label>
    <link:label id="lab_us-gaap_InvestmentBuildingAndBuildingImprovements_label_en-US" xlink:label="lab_us-gaap_InvestmentBuildingAndBuildingImprovements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investment Building and Building Improvements</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentBuildingAndBuildingImprovements" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InvestmentBuildingAndBuildingImprovements"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InvestmentBuildingAndBuildingImprovements" xlink:to="lab_us-gaap_InvestmentBuildingAndBuildingImprovements" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_019dbc7a-b1cb-70f9-9073-6a6726fb9993_terseLabel_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Award vesting rights, percentage</link:label>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_label_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage" xlink:to="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_TwoCommercialPlaceNorfolkVAMember_019dbc7a-b287-72b9-aa2b-d6b4ef5c3ef9_terseLabel_en-US" xlink:label="lab_opi_TwoCommercialPlaceNorfolkVAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Two Commercial Place, Norfolk, VA</link:label>
    <link:label id="lab_opi_TwoCommercialPlaceNorfolkVAMember_label_en-US" xlink:label="lab_opi_TwoCommercialPlaceNorfolkVAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Two Commercial Place, Norfolk, VA [Member]</link:label>
    <link:label id="lab_opi_TwoCommercialPlaceNorfolkVAMember_documentation_en-US" xlink:label="lab_opi_TwoCommercialPlaceNorfolkVAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Two commercial place [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_TwoCommercialPlaceNorfolkVAMember" xlink:href="opi-20251231.xsd#opi_TwoCommercialPlaceNorfolkVAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_TwoCommercialPlaceNorfolkVAMember" xlink:to="lab_opi_TwoCommercialPlaceNorfolkVAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SupplementalDisclosureOfCashCashEquivalentsAndRestrictedCashAbstract_019dbc7a-b1cb-7249-84ea-87cea5fee884_terseLabel_en-US" xlink:label="lab_opi_SupplementalDisclosureOfCashCashEquivalentsAndRestrictedCashAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">SUPPLEMENTAL DISCLOSURE OF CASH, CASH EQUIVALENTS AND RESTRICTED CASH:</link:label>
    <link:label id="lab_opi_SupplementalDisclosureOfCashCashEquivalentsAndRestrictedCashAbstract_label_en-US" xlink:label="lab_opi_SupplementalDisclosureOfCashCashEquivalentsAndRestrictedCashAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Supplemental Disclosure Of Cash, Cash Equivalents And Restricted Cash [Abstract]</link:label>
    <link:label id="lab_opi_SupplementalDisclosureOfCashCashEquivalentsAndRestrictedCashAbstract_documentation_en-US" xlink:label="lab_opi_SupplementalDisclosureOfCashCashEquivalentsAndRestrictedCashAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Supplemental Disclosure Of Cash, Cash Equivalents And Restricted Cash</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SupplementalDisclosureOfCashCashEquivalentsAndRestrictedCashAbstract" xlink:href="opi-20251231.xsd#opi_SupplementalDisclosureOfCashCashEquivalentsAndRestrictedCashAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SupplementalDisclosureOfCashCashEquivalentsAndRestrictedCashAbstract" xlink:to="lab_opi_SupplementalDisclosureOfCashCashEquivalentsAndRestrictedCashAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage_019dbc7a-b287-7428-b711-b99b2ad42f42_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate (as a percent)</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Interest Rate, Stated Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:to="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019dbc7a-b286-7be8-a425-cf9f2c619ad2_terseLabel_en-US" xlink:label="lab_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Investment, Name [Axis]</link:label>
    <link:label id="lab_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_label_en-US" xlink:label="lab_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investment, Name [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="lab_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstatePropertiesDomain_019dbc7a-b30c-7092-9f17-0196b0571b92_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstatePropertiesDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate Properties [Domain]</link:label>
    <link:label id="lab_us-gaap_RealEstatePropertiesDomain_label_en-US" xlink:label="lab_us-gaap_RealEstatePropertiesDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Properties [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstatePropertiesDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstatePropertiesDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstatePropertiesDomain" xlink:to="lab_us-gaap_RealEstatePropertiesDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityVoluntaryFilers_019dbc7a-b287-7dcc-938a-e2fcf290a649_terseLabel_en-US" xlink:label="lab_dei_EntityVoluntaryFilers" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Voluntary Filers</link:label>
    <link:label id="lab_dei_EntityVoluntaryFilers_label_en-US" xlink:label="lab_dei_EntityVoluntaryFilers" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Voluntary Filers</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityVoluntaryFilers" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityVoluntaryFilers"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityVoluntaryFilers" xlink:to="lab_dei_EntityVoluntaryFilers" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_CommonStockDividendsOrdinaryIncomeDistributionPercentage_019dbc7a-b286-7b29-b623-ef5c7d0a9514_verboseLabel_en-US" xlink:label="lab_opi_CommonStockDividendsOrdinaryIncomeDistributionPercentage" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Characterization of Distribution, Ordinary Income</link:label>
    <link:label id="lab_opi_CommonStockDividendsOrdinaryIncomeDistributionPercentage_label_en-US" xlink:label="lab_opi_CommonStockDividendsOrdinaryIncomeDistributionPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock, Dividends Ordinary Income Distribution Percentage</link:label>
    <link:label id="lab_opi_CommonStockDividendsOrdinaryIncomeDistributionPercentage_documentation_en-US" xlink:label="lab_opi_CommonStockDividendsOrdinaryIncomeDistributionPercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the percentage of ordinary income distributed as dividend on common stock.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_CommonStockDividendsOrdinaryIncomeDistributionPercentage" xlink:href="opi-20251231.xsd#opi_CommonStockDividendsOrdinaryIncomeDistributionPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_CommonStockDividendsOrdinaryIncomeDistributionPercentage" xlink:to="lab_opi_CommonStockDividendsOrdinaryIncomeDistributionPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SterlingParkBusinessCenterSterlingVAMember_019dbc7a-b287-7ebc-afeb-494870b24761_terseLabel_en-US" xlink:label="lab_opi_SterlingParkBusinessCenterSterlingVAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sterling Park Business Center, Sterling, VA</link:label>
    <link:label id="lab_opi_SterlingParkBusinessCenterSterlingVAMember_label_en-US" xlink:label="lab_opi_SterlingParkBusinessCenterSterlingVAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sterling Park Business Center, Sterling, VA [Member]</link:label>
    <link:label id="lab_opi_SterlingParkBusinessCenterSterlingVAMember_documentation_en-US" xlink:label="lab_opi_SterlingParkBusinessCenterSterlingVAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sterling Park Business Center, Sterling, VA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SterlingParkBusinessCenterSterlingVAMember" xlink:href="opi-20251231.xsd#opi_SterlingParkBusinessCenterSterlingVAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SterlingParkBusinessCenterSterlingVAMember" xlink:to="lab_opi_SterlingParkBusinessCenterSterlingVAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A625IndianaAvenueWashingtonDCMember_019dbc7a-b287-70b7-b907-41a5fcc41390_terseLabel_en-US" xlink:label="lab_opi_A625IndianaAvenueWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">625 Indiana Avenue, Washington DC</link:label>
    <link:label id="lab_opi_A625IndianaAvenueWashingtonDCMember_label_en-US" xlink:label="lab_opi_A625IndianaAvenueWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">625 Indiana Avenue, Washington, DC [Member]</link:label>
    <link:label id="lab_opi_A625IndianaAvenueWashingtonDCMember_documentation_en-US" xlink:label="lab_opi_A625IndianaAvenueWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">625 Indiana Avenue, Washington, DC</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A625IndianaAvenueWashingtonDCMember" xlink:href="opi-20251231.xsd#opi_A625IndianaAvenueWashingtonDCMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A625IndianaAvenueWashingtonDCMember" xlink:to="lab_opi_A625IndianaAvenueWashingtonDCMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_Land_019dbc7a-b1cb-77bf-9a30-39e7b6e99399_terseLabel_en-US" xlink:label="lab_us-gaap_Land" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Land</link:label>
    <link:label id="lab_us-gaap_Land_label_en-US" xlink:label="lab_us-gaap_Land" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Land</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Land" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Land"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Land" xlink:to="lab_us-gaap_Land" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccountsReceivableNet_019dbc7a-b1cb-7194-b7a4-86eb28e74042_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsReceivableNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rents receivable</link:label>
    <link:label id="lab_us-gaap_AccountsReceivableNet_label_en-US" xlink:label="lab_us-gaap_AccountsReceivableNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Receivable, after Allowance for Credit Loss</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsReceivableNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsReceivableNet" xlink:to="lab_us-gaap_AccountsReceivableNet" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityRegistrantName_019dbc7a-b287-712f-8cda-75169505dbd4_terseLabel_en-US" xlink:label="lab_dei_EntityRegistrantName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Registrant Name</link:label>
    <link:label id="lab_dei_EntityRegistrantName_label_en-US" xlink:label="lab_dei_EntityRegistrantName" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Registrant Name</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityRegistrantName"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityRegistrantName" xlink:to="lab_dei_EntityRegistrantName" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SonestaInternationalHotelsCorporationMember_019dbc7a-b1cb-78d7-b8e6-b09f06c222ac_terseLabel_en-US" xlink:label="lab_opi_SonestaInternationalHotelsCorporationMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sonesta International Hotels Corporation</link:label>
    <link:label id="lab_opi_SonestaInternationalHotelsCorporationMember_label_en-US" xlink:label="lab_opi_SonestaInternationalHotelsCorporationMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sonesta International Hotels Corporation [Member]</link:label>
    <link:label id="lab_opi_SonestaInternationalHotelsCorporationMember_documentation_en-US" xlink:label="lab_opi_SonestaInternationalHotelsCorporationMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sonesta International Hotels Corporation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SonestaInternationalHotelsCorporationMember" xlink:href="opi-20251231.xsd#opi_SonestaInternationalHotelsCorporationMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SonestaInternationalHotelsCorporationMember" xlink:to="lab_opi_SonestaInternationalHotelsCorporationMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_StkPrcOrTsrEstimationMethodTextBlock_terseLabel_en-US" xlink:label="lab_ecd_StkPrcOrTsrEstimationMethodTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stock Price or TSR Estimation Method</link:label>
    <link:label id="lab_ecd_StkPrcOrTsrEstimationMethodTextBlock_label_en-US" xlink:label="lab_ecd_StkPrcOrTsrEstimationMethodTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Price or TSR Estimation Method [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_StkPrcOrTsrEstimationMethodTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_StkPrcOrTsrEstimationMethodTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_StkPrcOrTsrEstimationMethodTextBlock" xlink:to="lab_ecd_StkPrcOrTsrEstimationMethodTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RealEstateRevenueNetMember_019dbc7a-b286-76fd-94cc-2262c36c6914_terseLabel_en-US" xlink:label="lab_opi_RealEstateRevenueNetMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Annualized Rental Income, Excluding Properties Classified as Discontinued Operations</link:label>
    <link:label id="lab_opi_RealEstateRevenueNetMember_label_en-US" xlink:label="lab_opi_RealEstateRevenueNetMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Revenue Net [Member]</link:label>
    <link:label id="lab_opi_RealEstateRevenueNetMember_documentation_en-US" xlink:label="lab_opi_RealEstateRevenueNetMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The revenue from real estate operations during the reporting period in the normal course of business, after deducting returns, allowances and discounts, when it serves as a benchmark in a concentration of risk calculation.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RealEstateRevenueNetMember" xlink:href="opi-20251231.xsd#opi_RealEstateRevenueNetMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RealEstateRevenueNetMember" xlink:to="lab_opi_RealEstateRevenueNetMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAccumulatedDepreciationOtherDeductions_019dbc7a-b1cb-7502-a233-db4e8de2b43a_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAccumulatedDepreciationOtherDeductions" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Cost basis adjustment</link:label>
    <link:label id="lab_us-gaap_RealEstateAccumulatedDepreciationOtherDeductions_label_en-US" xlink:label="lab_us-gaap_RealEstateAccumulatedDepreciationOtherDeductions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation, Other Deduction</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAccumulatedDepreciationOtherDeductions" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAccumulatedDepreciationOtherDeductions"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAccumulatedDepreciationOtherDeductions" xlink:to="lab_us-gaap_RealEstateAccumulatedDepreciationOtherDeductions" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionIncentiveFeePercentOfNetOperatingProfit_019dbc7a-b287-755e-b9f7-33ff5d402982_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionIncentiveFeePercentOfNetOperatingProfit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Incentive fee, percent of net operating profit</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionIncentiveFeePercentOfNetOperatingProfit_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionIncentiveFeePercentOfNetOperatingProfit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Incentive Fee, Percent Of Net Operating Profit</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionIncentiveFeePercentOfNetOperatingProfit_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionIncentiveFeePercentOfNetOperatingProfit" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Incentive Fee, Percent Of Net Operating Profit</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionIncentiveFeePercentOfNetOperatingProfit" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionIncentiveFeePercentOfNetOperatingProfit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionIncentiveFeePercentOfNetOperatingProfit" xlink:to="lab_opi_RelatedPartyTransactionIncentiveFeePercentOfNetOperatingProfit" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstatePropertiesAxis_019dbc7a-b287-7187-aae2-5d94001df9f6_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstatePropertiesAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate Property Ownership [Axis]</link:label>
    <link:label id="lab_us-gaap_RealEstatePropertiesAxis_label_en-US" xlink:label="lab_us-gaap_RealEstatePropertiesAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Property Ownership [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstatePropertiesAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstatePropertiesAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstatePropertiesAxis" xlink:to="lab_us-gaap_RealEstatePropertiesAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_019dbc7a-b1cb-772a-aad0-b36e0122b741_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Granted (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019dbc7a-b287-7875-801c-39813d798f9e_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Related Party [Axis]</link:label>
    <link:label id="lab_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_label_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related and Nonrelated Parties [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="lab_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionBrandPromotionFeePercentOfGrossRevenues_019dbc7a-b286-7bb7-9248-f64cf3aedd86_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionBrandPromotionFeePercentOfGrossRevenues" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Brand promotion fee, percent of gross revenues</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBrandPromotionFeePercentOfGrossRevenues_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionBrandPromotionFeePercentOfGrossRevenues" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Brand Promotion Fee, Percent Of Gross Revenues</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBrandPromotionFeePercentOfGrossRevenues_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionBrandPromotionFeePercentOfGrossRevenues" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Brand Promotion Fee, Percent Of Gross Revenues</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionBrandPromotionFeePercentOfGrossRevenues" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionBrandPromotionFeePercentOfGrossRevenues"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionBrandPromotionFeePercentOfGrossRevenues" xlink:to="lab_opi_RelatedPartyTransactionBrandPromotionFeePercentOfGrossRevenues" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit_019dbc8d-3791-7132-8e2d-d19ab88328e3_negatedLabel_en-US" xlink:label="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Repayments on revolving credit facility</link:label>
    <link:label id="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit_label_en-US" xlink:label="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Repayments of Long-Term Lines of Credit</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RepaymentsOfLongTermLinesOfCredit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:to="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_RestatementDateAxis_terseLabel_en-US" xlink:label="lab_ecd_RestatementDateAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Restatement Determination Date:</link:label>
    <link:label id="lab_ecd_RestatementDateAxis_label_en-US" xlink:label="lab_ecd_RestatementDateAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Restatement Determination Date [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_RestatementDateAxis" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_RestatementDateAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_RestatementDateAxis" xlink:to="lab_ecd_RestatementDateAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ExtinguishmentOfDebtInExchangeForSeniorPriorityGuaranteedNotes_019dbc90-0aba-779b-969e-039d9a0d7820_negatedTerseLabel_en-US" xlink:label="lab_opi_ExtinguishmentOfDebtInExchangeForSeniorPriorityGuaranteedNotes" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Extinguishment of unsecured senior notes in exchange for senior priority guaranteed unsecured notes</link:label>
    <link:label id="lab_opi_ExtinguishmentOfDebtInExchangeForSeniorPriorityGuaranteedNotes_label_en-US" xlink:label="lab_opi_ExtinguishmentOfDebtInExchangeForSeniorPriorityGuaranteedNotes" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Extinguishment Of Debt In Exchange For Senior Priority Guaranteed Notes</link:label>
    <link:label id="lab_opi_ExtinguishmentOfDebtInExchangeForSeniorPriorityGuaranteedNotes_documentation_en-US" xlink:label="lab_opi_ExtinguishmentOfDebtInExchangeForSeniorPriorityGuaranteedNotes" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Extinguishment Of Debt In Exchange For Senior Priority Guaranteed Notes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ExtinguishmentOfDebtInExchangeForSeniorPriorityGuaranteedNotes" xlink:href="opi-20251231.xsd#opi_ExtinguishmentOfDebtInExchangeForSeniorPriorityGuaranteedNotes"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ExtinguishmentOfDebtInExchangeForSeniorPriorityGuaranteedNotes" xlink:to="lab_opi_ExtinguishmentOfDebtInExchangeForSeniorPriorityGuaranteedNotes" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A5353YellowstoneRoadCheyenneWYMember_019dbc7a-b287-7000-9f4d-74a8d5250e1c_terseLabel_en-US" xlink:label="lab_opi_A5353YellowstoneRoadCheyenneWYMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">5353 Yellowstone Road, Cheyenne, WY</link:label>
    <link:label id="lab_opi_A5353YellowstoneRoadCheyenneWYMember_label_en-US" xlink:label="lab_opi_A5353YellowstoneRoadCheyenneWYMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">5353 Yellowstone Road, Cheyenne, WY [Member]</link:label>
    <link:label id="lab_opi_A5353YellowstoneRoadCheyenneWYMember_documentation_en-US" xlink:label="lab_opi_A5353YellowstoneRoadCheyenneWYMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">5353 Yellowstone road [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A5353YellowstoneRoadCheyenneWYMember" xlink:href="opi-20251231.xsd#opi_A5353YellowstoneRoadCheyenneWYMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A5353YellowstoneRoadCheyenneWYMember" xlink:to="lab_opi_A5353YellowstoneRoadCheyenneWYMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_TrdArrIndName_terseLabel_en-US" xlink:label="lab_ecd_TrdArrIndName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Name</link:label>
    <link:label id="lab_ecd_TrdArrIndName_label_en-US" xlink:label="lab_ecd_TrdArrIndName" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Trading Arrangement, Individual Name</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_TrdArrIndName" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_TrdArrIndName"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_TrdArrIndName" xlink:to="lab_ecd_TrdArrIndName" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A8800TinicumBoulevardPhiladelphiaPAMember_019dbc7a-b287-7ba0-bf8f-54fa6badf81d_terseLabel_en-US" xlink:label="lab_opi_A8800TinicumBoulevardPhiladelphiaPAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">8800 Tinicum Boulevard, Philadelphia, PA</link:label>
    <link:label id="lab_opi_A8800TinicumBoulevardPhiladelphiaPAMember_label_en-US" xlink:label="lab_opi_A8800TinicumBoulevardPhiladelphiaPAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">8800 Tinicum Boulevard, Philadelphia, PA [Member]</link:label>
    <link:label id="lab_opi_A8800TinicumBoulevardPhiladelphiaPAMember_documentation_en-US" xlink:label="lab_opi_A8800TinicumBoulevardPhiladelphiaPAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">8800 Tinicum Boulevard, Philadelphia, PA [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A8800TinicumBoulevardPhiladelphiaPAMember" xlink:href="opi-20251231.xsd#opi_A8800TinicumBoulevardPhiladelphiaPAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A8800TinicumBoulevardPhiladelphiaPAMember" xlink:to="lab_opi_A8800TinicumBoulevardPhiladelphiaPAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentFaceAmount_019dbc7a-b1cb-7c8a-9ff3-ea63a3496480_verboseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentFaceAmount" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Aggregate principal amount</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentFaceAmount_019dbc7a-b1cb-739f-9480-b6433ea2b98f_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentFaceAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Principal balance</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentFaceAmount_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentFaceAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Face Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentFaceAmount" xlink:to="lab_us-gaap_DebtInstrumentFaceAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SonestaManagementAgreementPeriodTwoMember_019dbc7a-b287-79f0-abdc-ccfcd35ac521_terseLabel_en-US" xlink:label="lab_opi_SonestaManagementAgreementPeriodTwoMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sonesta Management Agreement, Period Two</link:label>
    <link:label id="lab_opi_SonestaManagementAgreementPeriodTwoMember_label_en-US" xlink:label="lab_opi_SonestaManagementAgreementPeriodTwoMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sonesta Management Agreement, Period Two [Member]</link:label>
    <link:label id="lab_opi_SonestaManagementAgreementPeriodTwoMember_documentation_en-US" xlink:label="lab_opi_SonestaManagementAgreementPeriodTwoMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sonesta Management Agreement, Period Two</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SonestaManagementAgreementPeriodTwoMember" xlink:href="opi-20251231.xsd#opi_SonestaManagementAgreementPeriodTwoMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SonestaManagementAgreementPeriodTwoMember" xlink:to="lab_opi_SonestaManagementAgreementPeriodTwoMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ReorganizationItemsPaid_019dbc91-72f6-78ef-b241-638c28afa304_terseLabel_en-US" xlink:label="lab_opi_ReorganizationItemsPaid" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash paid for reorganization costs</link:label>
    <link:label id="lab_opi_ReorganizationItemsPaid_label_en-US" xlink:label="lab_opi_ReorganizationItemsPaid" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reorganization Items Paid</link:label>
    <link:label id="lab_opi_ReorganizationItemsPaid_documentation_en-US" xlink:label="lab_opi_ReorganizationItemsPaid" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Reorganization Items Paid</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ReorganizationItemsPaid" xlink:href="opi-20251231.xsd#opi_ReorganizationItemsPaid"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ReorganizationItemsPaid" xlink:to="lab_opi_ReorganizationItemsPaid" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AwardsCloseToMnpiDiscIndName_terseLabel_en-US" xlink:label="lab_ecd_AwardsCloseToMnpiDiscIndName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Name</link:label>
    <link:label id="lab_ecd_AwardsCloseToMnpiDiscIndName_label_en-US" xlink:label="lab_ecd_AwardsCloseToMnpiDiscIndName" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Awards Close in Time to MNPI Disclosures, Individual Name</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AwardsCloseToMnpiDiscIndName" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AwardsCloseToMnpiDiscIndName"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AwardsCloseToMnpiDiscIndName" xlink:to="lab_ecd_AwardsCloseToMnpiDiscIndName" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwo_019dbc7a-b287-7b64-be40-237f6e54bd2a_terseLabel_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2027</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwo_label_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right, Exercisable In Year Two</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwo_documentation_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwo" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the percentage as a concentration risk for termination right exercisable in year two from the balance sheet date.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwo" xlink:href="opi-20251231.xsd#opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwo"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwo" xlink:to="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearTwo" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_019dbc7a-b287-7fd0-84e2-8cd5b5091969_periodStartLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Unvested at the beginning of the period (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_019dbc7a-b287-732f-99bf-587446203603_periodEndLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Unvested at the end of the period (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AggtErrCompNotYetDeterminedTextBlock_terseLabel_en-US" xlink:label="lab_ecd_AggtErrCompNotYetDeterminedTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate Erroneous Compensation Not Yet Determined</link:label>
    <link:label id="lab_ecd_AggtErrCompNotYetDeterminedTextBlock_label_en-US" xlink:label="lab_ecd_AggtErrCompNotYetDeterminedTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Aggregate Erroneous Compensation Not Yet Determined [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AggtErrCompNotYetDeterminedTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AggtErrCompNotYetDeterminedTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AggtErrCompNotYetDeterminedTextBlock" xlink:to="lab_ecd_AggtErrCompNotYetDeterminedTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A51RioRoblesDriveSanJoseCAMember_019dbc7a-b30c-7cf2-9452-2cebf08d8f0f_terseLabel_en-US" xlink:label="lab_opi_A51RioRoblesDriveSanJoseCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">51 Rio Robles Drive, San Jose, CA</link:label>
    <link:label id="lab_opi_A51RioRoblesDriveSanJoseCAMember_label_en-US" xlink:label="lab_opi_A51RioRoblesDriveSanJoseCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">51 Rio Robles Drive, San Jose, CA [Member]</link:label>
    <link:label id="lab_opi_A51RioRoblesDriveSanJoseCAMember_documentation_en-US" xlink:label="lab_opi_A51RioRoblesDriveSanJoseCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">51 Rio Robles Drive, San Jose, CA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A51RioRoblesDriveSanJoseCAMember" xlink:href="opi-20251231.xsd#opi_A51RioRoblesDriveSanJoseCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A51RioRoblesDriveSanJoseCAMember" xlink:to="lab_opi_A51RioRoblesDriveSanJoseCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_IcfrAuditorAttestationFlag_019dbc7a-b1cb-71a5-9d57-8e236cf1eeeb_terseLabel_en-US" xlink:label="lab_dei_IcfrAuditorAttestationFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">ICFR Auditor Attestation Flag</link:label>
    <link:label id="lab_dei_IcfrAuditorAttestationFlag_label_en-US" xlink:label="lab_dei_IcfrAuditorAttestationFlag" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">ICFR Auditor Attestation Flag</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_IcfrAuditorAttestationFlag" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_IcfrAuditorAttestationFlag"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_IcfrAuditorAttestationFlag" xlink:to="lab_dei_IcfrAuditorAttestationFlag" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_TrusteesMember_019dbc7a-b287-73aa-bd93-f2451aa08da7_terseLabel_en-US" xlink:label="lab_opi_TrusteesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Trustees</link:label>
    <link:label id="lab_opi_TrusteesMember_label_en-US" xlink:label="lab_opi_TrusteesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Trustees [Member]</link:label>
    <link:label id="lab_opi_TrusteesMember_documentation_en-US" xlink:label="lab_opi_TrusteesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents trustees of the entity.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_TrusteesMember" xlink:href="opi-20251231.xsd#opi_TrusteesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_TrusteesMember" xlink:to="lab_opi_TrusteesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_AuditorFirmId_019dbc7a-b1cb-7567-a7ea-2b96f0e60186_terseLabel_en-US" xlink:label="lab_dei_AuditorFirmId" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Auditor Firm ID</link:label>
    <link:label id="lab_dei_AuditorFirmId_label_en-US" xlink:label="lab_dei_AuditorFirmId" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Auditor Firm ID</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AuditorFirmId" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_AuditorFirmId"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_AuditorFirmId" xlink:to="lab_dei_AuditorFirmId" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A6310HillsideCenterColumbiaMDMember_019dbc7a-b1cb-7639-8608-5ac6de5c0726_terseLabel_en-US" xlink:label="lab_opi_A6310HillsideCenterColumbiaMDMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">6310 Hillside Center, Columbia, MD</link:label>
    <link:label id="lab_opi_A6310HillsideCenterColumbiaMDMember_label_en-US" xlink:label="lab_opi_A6310HillsideCenterColumbiaMDMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">6310 Hillside Center, Columbia, MD [Member]</link:label>
    <link:label id="lab_opi_A6310HillsideCenterColumbiaMDMember_documentation_en-US" xlink:label="lab_opi_A6310HillsideCenterColumbiaMDMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">6310 Hillside Center, Columbia, MD</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A6310HillsideCenterColumbiaMDMember" xlink:href="opi-20251231.xsd#opi_A6310HillsideCenterColumbiaMDMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A6310HillsideCenterColumbiaMDMember" xlink:to="lab_opi_A6310HillsideCenterColumbiaMDMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfDebtConversionsTextBlock_019dbc7a-b287-735a-8eb7-f6d30f7d2312_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfDebtConversionsTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Senior Note Exchanges</link:label>
    <link:label id="lab_us-gaap_ScheduleOfDebtConversionsTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfDebtConversionsTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Debt Conversions [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDebtConversionsTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDebtConversionsTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfDebtConversionsTextBlock" xlink:to="lab_us-gaap_ScheduleOfDebtConversionsTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_IncentiveManagementFeeHighestAverageClosingPriceDuringThresholdFinalConsecutiveTradingDays_019dbc7a-b287-7552-b0b0-bd52cc09487d_terseLabel_en-US" xlink:label="lab_opi_IncentiveManagementFeeHighestAverageClosingPriceDuringThresholdFinalConsecutiveTradingDays" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Highest average closing price of our common shares, final consecutive trading days</link:label>
    <link:label id="lab_opi_IncentiveManagementFeeHighestAverageClosingPriceDuringThresholdFinalConsecutiveTradingDays_label_en-US" xlink:label="lab_opi_IncentiveManagementFeeHighestAverageClosingPriceDuringThresholdFinalConsecutiveTradingDays" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Incentive Management Fee, Highest Average Closing Price During Threshold Final Consecutive Trading Days</link:label>
    <link:label id="lab_opi_IncentiveManagementFeeHighestAverageClosingPriceDuringThresholdFinalConsecutiveTradingDays_documentation_en-US" xlink:label="lab_opi_IncentiveManagementFeeHighestAverageClosingPriceDuringThresholdFinalConsecutiveTradingDays" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Incentive Management Fee, Highest Average Closing Price During Threshold Final Consecutive Trading Days</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_IncentiveManagementFeeHighestAverageClosingPriceDuringThresholdFinalConsecutiveTradingDays" xlink:href="opi-20251231.xsd#opi_IncentiveManagementFeeHighestAverageClosingPriceDuringThresholdFinalConsecutiveTradingDays"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_IncentiveManagementFeeHighestAverageClosingPriceDuringThresholdFinalConsecutiveTradingDays" xlink:to="lab_opi_IncentiveManagementFeeHighestAverageClosingPriceDuringThresholdFinalConsecutiveTradingDays" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_NumberOfPropertiesCollateralized_019dbc7a-b287-7f1f-88a1-8831e05be1ca_terseLabel_en-US" xlink:label="lab_opi_NumberOfPropertiesCollateralized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of properties used to secured mortgage note</link:label>
    <link:label id="lab_opi_NumberOfPropertiesCollateralized_label_en-US" xlink:label="lab_opi_NumberOfPropertiesCollateralized" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number Of Properties Collateralized</link:label>
    <link:label id="lab_opi_NumberOfPropertiesCollateralized_documentation_en-US" xlink:label="lab_opi_NumberOfPropertiesCollateralized" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The number of properties serving as collateral for debt as of the balance sheet date.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_NumberOfPropertiesCollateralized" xlink:href="opi-20251231.xsd#opi_NumberOfPropertiesCollateralized"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_NumberOfPropertiesCollateralized" xlink:to="lab_opi_NumberOfPropertiesCollateralized" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyReimbursementExpense_019dbc7a-b286-7916-b770-0ba688b8fea2_negatedTerseLabel_en-US" xlink:label="lab_opi_RelatedPartyReimbursementExpense" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Reimbursement amounts</link:label>
    <link:label id="lab_opi_RelatedPartyReimbursementExpense_label_en-US" xlink:label="lab_opi_RelatedPartyReimbursementExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Reimbursement Expense</link:label>
    <link:label id="lab_opi_RelatedPartyReimbursementExpense_documentation_en-US" xlink:label="lab_opi_RelatedPartyReimbursementExpense" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Total expense amount to reimburse a related party.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyReimbursementExpense" xlink:href="opi-20251231.xsd#opi_RelatedPartyReimbursementExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyReimbursementExpense" xlink:to="lab_opi_RelatedPartyReimbursementExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_UnconsolidatedPropertiesMember_019dbc7a-b287-7605-a88b-ddff81b79d06_terseLabel_en-US" xlink:label="lab_us-gaap_UnconsolidatedPropertiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unconsolidated Properties</link:label>
    <link:label id="lab_us-gaap_UnconsolidatedPropertiesMember_label_en-US" xlink:label="lab_us-gaap_UnconsolidatedPropertiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Unconsolidated Properties [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnconsolidatedPropertiesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_UnconsolidatedPropertiesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UnconsolidatedPropertiesMember" xlink:to="lab_us-gaap_UnconsolidatedPropertiesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AmortizationOfFinancingCostsAndDiscounts_019dbc85-0b08-79e6-a76f-03359c1c60ac_terseLabel_en-US" xlink:label="lab_us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net amortization of debt premiums, discounts and issuance costs</link:label>
    <link:label id="lab_us-gaap_AmortizationOfFinancingCostsAndDiscounts_label_en-US" xlink:label="lab_us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amortization of Debt Issuance Costs and Discounts</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AmortizationOfFinancingCostsAndDiscounts"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:to="lab_us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_IncreaseDecreaseToRentalIncomeFromAmortizationInCapitalizedAboveAndBelowMarketLeases_019dbc7a-b1cb-7138-a2a3-881125e4ce89_terseLabel_en-US" xlink:label="lab_opi_IncreaseDecreaseToRentalIncomeFromAmortizationInCapitalizedAboveAndBelowMarketLeases" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net increase (decrease) to rental income</link:label>
    <link:label id="lab_opi_IncreaseDecreaseToRentalIncomeFromAmortizationInCapitalizedAboveAndBelowMarketLeases_label_en-US" xlink:label="lab_opi_IncreaseDecreaseToRentalIncomeFromAmortizationInCapitalizedAboveAndBelowMarketLeases" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) to Rental Income from Amortization in Capitalized above and below Market Leases</link:label>
    <link:label id="lab_opi_IncreaseDecreaseToRentalIncomeFromAmortizationInCapitalizedAboveAndBelowMarketLeases_documentation_en-US" xlink:label="lab_opi_IncreaseDecreaseToRentalIncomeFromAmortizationInCapitalizedAboveAndBelowMarketLeases" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the increase or decrease in rental income from amortization of capitalized above market and below market leases.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_IncreaseDecreaseToRentalIncomeFromAmortizationInCapitalizedAboveAndBelowMarketLeases" xlink:href="opi-20251231.xsd#opi_IncreaseDecreaseToRentalIncomeFromAmortizationInCapitalizedAboveAndBelowMarketLeases"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_IncreaseDecreaseToRentalIncomeFromAmortizationInCapitalizedAboveAndBelowMarketLeases" xlink:to="lab_opi_IncreaseDecreaseToRentalIncomeFromAmortizationInCapitalizedAboveAndBelowMarketLeases" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionConstructionSupervisionFeesAsPercentageOfConstructionCosts_019dbc7a-b30c-7fa6-b56e-91b2f32f3433_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionConstructionSupervisionFeesAsPercentageOfConstructionCosts" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Construction supervision fees as percentage of construction costs</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionConstructionSupervisionFeesAsPercentageOfConstructionCosts_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionConstructionSupervisionFeesAsPercentageOfConstructionCosts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction Construction Supervision Fees as Percentage of Construction Costs</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionConstructionSupervisionFeesAsPercentageOfConstructionCosts_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionConstructionSupervisionFeesAsPercentageOfConstructionCosts" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the construction supervision fees as a percentage of construction costs pursuant to property management agreement with related parties.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionConstructionSupervisionFeesAsPercentageOfConstructionCosts" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionConstructionSupervisionFeesAsPercentageOfConstructionCosts"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionConstructionSupervisionFeesAsPercentageOfConstructionCosts" xlink:to="lab_opi_RelatedPartyTransactionConstructionSupervisionFeesAsPercentageOfConstructionCosts" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EarningsPerSharePolicyTextBlock_019dbc7a-b286-7257-b749-a673bfcfff58_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerSharePolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Per Common Share Amounts</link:label>
    <link:label id="lab_us-gaap_EarningsPerSharePolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_EarningsPerSharePolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Earnings Per Share, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerSharePolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerSharePolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerSharePolicyTextBlock" xlink:to="lab_us-gaap_EarningsPerSharePolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SeniorNotesMember_019dbc7a-b1cb-7497-af07-ef23d0f8f039_terseLabel_en-US" xlink:label="lab_us-gaap_SeniorNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior Notes</link:label>
    <link:label id="lab_us-gaap_SeniorNotesMember_label_en-US" xlink:label="lab_us-gaap_SeniorNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Senior Notes [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SeniorNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SeniorNotesMember" xlink:to="lab_us-gaap_SeniorNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AllExecutiveCategoriesMember_terseLabel_en-US" xlink:label="lab_ecd_AllExecutiveCategoriesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">All Executive Categories</link:label>
    <link:label id="lab_ecd_AllExecutiveCategoriesMember_label_en-US" xlink:label="lab_ecd_AllExecutiveCategoriesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">All Executive Categories [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AllExecutiveCategoriesMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AllExecutiveCategoriesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AllExecutiveCategoriesMember" xlink:to="lab_ecd_AllExecutiveCategoriesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockValue_019dbc7a-b286-7a47-9720-6fcf9366cebf_verboseLabel_en-US" xlink:label="lab_us-gaap_CommonStockValue" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Common shares of beneficial interest, $.01 par value: 250,000,000 shares authorized, 73,941,128 and 69,824,743 shares issued and outstanding, respectively</link:label>
    <link:label id="lab_us-gaap_CommonStockValue_019dbc7a-b286-7690-a161-1819ac18b567_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common shares of beneficial interest</link:label>
    <link:label id="lab_us-gaap_CommonStockValue_label_en-US" xlink:label="lab_us-gaap_CommonStockValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock, Value, Issued</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockValue" xlink:to="lab_us-gaap_CommonStockValue" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A1401KStreetNWWashingtonDCMember_019dbc7a-b286-7c8d-a9e1-8ed424ae3921_terseLabel_en-US" xlink:label="lab_opi_A1401KStreetNWWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">1401 K Street, NW, Washington DC</link:label>
    <link:label id="lab_opi_A1401KStreetNWWashingtonDCMember_label_en-US" xlink:label="lab_opi_A1401KStreetNWWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">1401 K Street, NW, Washington DC [Member]</link:label>
    <link:label id="lab_opi_A1401KStreetNWWashingtonDCMember_documentation_en-US" xlink:label="lab_opi_A1401KStreetNWWashingtonDCMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">1401 K Street, NW, Washington DC [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A1401KStreetNWWashingtonDCMember" xlink:href="opi-20251231.xsd#opi_A1401KStreetNWWashingtonDCMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A1401KStreetNWWashingtonDCMember" xlink:to="lab_opi_A1401KStreetNWWashingtonDCMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SegmentOperatingActivitiesDomain_019dbc7a-b1cb-77a7-b63b-53639730ebd0_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentOperatingActivitiesDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating Activities [Domain]</link:label>
    <link:label id="lab_us-gaap_SegmentOperatingActivitiesDomain_label_en-US" xlink:label="lab_us-gaap_SegmentOperatingActivitiesDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Activities [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentOperatingActivitiesDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentOperatingActivitiesDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentOperatingActivitiesDomain" xlink:to="lab_us-gaap_SegmentOperatingActivitiesDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_TitleOfIndividualAxis_019dbc7a-b287-7ef1-bbf6-3e2b70c45fa4_terseLabel_en-US" xlink:label="lab_srt_TitleOfIndividualAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Title and Position [Axis]</link:label>
    <link:label id="lab_srt_TitleOfIndividualAxis_label_en-US" xlink:label="lab_srt_TitleOfIndividualAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Title and Position [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_TitleOfIndividualAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_TitleOfIndividualAxis" xlink:to="lab_srt_TitleOfIndividualAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommitmentsAndContingencies_019dbc7a-b286-725a-b099-b6b227b4e4e5_terseLabel_en-US" xlink:label="lab_us-gaap_CommitmentsAndContingencies" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Commitments and contingencies</link:label>
    <link:label id="lab_us-gaap_CommitmentsAndContingencies_label_en-US" xlink:label="lab_us-gaap_CommitmentsAndContingencies" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Commitments and Contingencies</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommitmentsAndContingencies" xlink:to="lab_us-gaap_CommitmentsAndContingencies" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A711S14thAvenueSaffordAZMember_019dbc7a-b287-7301-abbc-f7a9bba72945_terseLabel_en-US" xlink:label="lab_opi_A711S14thAvenueSaffordAZMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">711 S 14th Avenue, Safford, AZ</link:label>
    <link:label id="lab_opi_A711S14thAvenueSaffordAZMember_label_en-US" xlink:label="lab_opi_A711S14thAvenueSaffordAZMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">711 S 14th Avenue, Safford, AZ [Member]</link:label>
    <link:label id="lab_opi_A711S14thAvenueSaffordAZMember_documentation_en-US" xlink:label="lab_opi_A711S14thAvenueSaffordAZMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">711 S 14th Avenue, Safford, AZ</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A711S14thAvenueSaffordAZMember" xlink:href="opi-20251231.xsd#opi_A711S14thAvenueSaffordAZMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A711S14thAvenueSaffordAZMember" xlink:to="lab_opi_A711S14thAvenueSaffordAZMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SeniorNotesAndMortgagesMember_019dbc7a-b286-7022-914d-1b9f7efd7444_terseLabel_en-US" xlink:label="lab_opi_SeniorNotesAndMortgagesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior Notes and Mortgages</link:label>
    <link:label id="lab_opi_SeniorNotesAndMortgagesMember_label_en-US" xlink:label="lab_opi_SeniorNotesAndMortgagesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Senior Notes And Mortgages [Member]</link:label>
    <link:label id="lab_opi_SeniorNotesAndMortgagesMember_documentation_en-US" xlink:label="lab_opi_SeniorNotesAndMortgagesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Senior Notes And Mortgages [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SeniorNotesAndMortgagesMember" xlink:href="opi-20251231.xsd#opi_SeniorNotesAndMortgagesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SeniorNotesAndMortgagesMember" xlink:to="lab_opi_SeniorNotesAndMortgagesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A8272MortgageNotesPayableMember_019dbcab-4bc2-7088-8a1d-a16cb91c9fb9_terseLabel_en-US" xlink:label="lab_opi_A8272MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mortgage note payable, 8.272% interest rate, due in 2028</link:label>
    <link:label id="lab_opi_A8272MortgageNotesPayableMember_label_en-US" xlink:label="lab_opi_A8272MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">8.272% Mortgage Notes Payable [Member]</link:label>
    <link:label id="lab_opi_A8272MortgageNotesPayableMember_documentation_en-US" xlink:label="lab_opi_A8272MortgageNotesPayableMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">8.272% Mortgage Notes Payable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A8272MortgageNotesPayableMember" xlink:href="opi-20251231.xsd#opi_A8272MortgageNotesPayableMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A8272MortgageNotesPayableMember" xlink:to="lab_opi_A8272MortgageNotesPayableMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A14660LeeRoadChantillyVAMember_019dbc7a-b286-7764-9a80-8c574a7217bf_terseLabel_en-US" xlink:label="lab_opi_A14660LeeRoadChantillyVAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">14660 Lee Road, Chantilly, VA</link:label>
    <link:label id="lab_opi_A14660LeeRoadChantillyVAMember_label_en-US" xlink:label="lab_opi_A14660LeeRoadChantillyVAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">14660 Lee Road, Chantilly, VA [Member]</link:label>
    <link:label id="lab_opi_A14660LeeRoadChantillyVAMember_documentation_en-US" xlink:label="lab_opi_A14660LeeRoadChantillyVAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">14660 Lee Road, Chantilly, VA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A14660LeeRoadChantillyVAMember" xlink:href="opi-20251231.xsd#opi_A14660LeeRoadChantillyVAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A14660LeeRoadChantillyVAMember" xlink:to="lab_opi_A14660LeeRoadChantillyVAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock_019dbc7a-b287-7c7a-b46a-2026d0bc8af9_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Summary of Shares Granted And Vested Under The Terms of The Entity's 2009 Plan</link:label>
    <link:label id="lab_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Nonvested Share Activity [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A4712SouthparkBoulevardEllenwoodGAMember_019dbc7a-b1cb-7cf9-baad-1810cecd1742_terseLabel_en-US" xlink:label="lab_opi_A4712SouthparkBoulevardEllenwoodGAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">4712 Southpark Boulevard, Ellenwood, GA</link:label>
    <link:label id="lab_opi_A4712SouthparkBoulevardEllenwoodGAMember_label_en-US" xlink:label="lab_opi_A4712SouthparkBoulevardEllenwoodGAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">4712 Southpark Boulevard, Ellenwood, GA [Member]</link:label>
    <link:label id="lab_opi_A4712SouthparkBoulevardEllenwoodGAMember_documentation_en-US" xlink:label="lab_opi_A4712SouthparkBoulevardEllenwoodGAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">4712 Southpark Boulevard, Ellenwood, GA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A4712SouthparkBoulevardEllenwoodGAMember" xlink:href="opi-20251231.xsd#opi_A4712SouthparkBoulevardEllenwoodGAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A4712SouthparkBoulevardEllenwoodGAMember" xlink:to="lab_opi_A4712SouthparkBoulevardEllenwoodGAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityMethodInvestmentsPolicy_019dbc7a-b1cb-7271-a318-390360e939ce_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentsPolicy" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity Method Investments</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentsPolicy_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentsPolicy" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investments [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentsPolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestmentsPolicy"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentsPolicy" xlink:to="lab_us-gaap_EquityMethodInvestmentsPolicy" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage_019dbc7a-b1cb-77bf-9824-a53fb19e14d7_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage of ownership interest</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage_019dbc7a-b1cb-7640-8184-56549f568df9_netLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:role="http://www.xbrl.org/2009/role/netLabel" xlink:type="resource" xml:lang="en-US">OPI Ownership</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Ownership Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:to="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_019dbc7a-b287-7aa4-8d1b-93c5dde60fa8_terseLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Numerators:</link:label>
    <link:label id="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_label_en-US" xlink:label="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Income (Loss) Available to Common Stockholders, Basic [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract" xlink:to="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter_019dbc7a-b287-7bb1-817f-f9330ef38df5_terseLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Thereafter</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received, after Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter" xlink:to="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ConcentrationRiskLineItems_019dbc7a-b1cb-7e23-a044-8c4fdaf4a4c9_terseLabel_en-US" xlink:label="lab_us-gaap_ConcentrationRiskLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Concentration Risk [Line Items]</link:label>
    <link:label id="lab_us-gaap_ConcentrationRiskLineItems_label_en-US" xlink:label="lab_us-gaap_ConcentrationRiskLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConcentrationRiskLineItems" xlink:to="lab_us-gaap_ConcentrationRiskLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RealEstateAccumulatedDepreciationImpairmentOrWritedowns_019dbc7a-b1cb-72b8-9c05-f1a63074fc61_negatedTerseLabel_en-US" xlink:label="lab_opi_RealEstateAccumulatedDepreciationImpairmentOrWritedowns" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Loss on asset impairment</link:label>
    <link:label id="lab_opi_RealEstateAccumulatedDepreciationImpairmentOrWritedowns_label_en-US" xlink:label="lab_opi_RealEstateAccumulatedDepreciationImpairmentOrWritedowns" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Accumulated Depreciation Impairment Or Writedowns</link:label>
    <link:label id="lab_opi_RealEstateAccumulatedDepreciationImpairmentOrWritedowns_documentation_en-US" xlink:label="lab_opi_RealEstateAccumulatedDepreciationImpairmentOrWritedowns" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of impairment loss on the property.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RealEstateAccumulatedDepreciationImpairmentOrWritedowns" xlink:href="opi-20251231.xsd#opi_RealEstateAccumulatedDepreciationImpairmentOrWritedowns"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RealEstateAccumulatedDepreciationImpairmentOrWritedowns" xlink:to="lab_opi_RealEstateAccumulatedDepreciationImpairmentOrWritedowns" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_PeoActuallyPaidCompAmt_terseLabel_en-US" xlink:label="lab_ecd_PeoActuallyPaidCompAmt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">PEO Actually Paid Compensation Amount</link:label>
    <link:label id="lab_ecd_PeoActuallyPaidCompAmt_label_en-US" xlink:label="lab_ecd_PeoActuallyPaidCompAmt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">PEO Actually Paid Compensation Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_PeoActuallyPaidCompAmt" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_PeoActuallyPaidCompAmt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_PeoActuallyPaidCompAmt" xlink:to="lab_ecd_PeoActuallyPaidCompAmt" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionNumberOfRenewalOptions_019dbc7a-b287-7362-911d-90bd0a64ecae_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionNumberOfRenewalOptions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of renewal options</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionNumberOfRenewalOptions_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionNumberOfRenewalOptions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Number Of Renewal Options</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionNumberOfRenewalOptions_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionNumberOfRenewalOptions" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Number Of Renewal Options</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionNumberOfRenewalOptions" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionNumberOfRenewalOptions"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionNumberOfRenewalOptions" xlink:to="lab_opi_RelatedPartyTransactionNumberOfRenewalOptions" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearTwo_019dbc7a-b287-7acf-8060-22b359067889_terseLabel_en-US" xlink:label="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2027 (in shares)</link:label>
    <link:label id="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearTwo_label_en-US" xlink:label="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share Based Compensation Arrangement By Share Based Payment Award, Nonvested Shares Scheduled To Vest In Year Two</link:label>
    <link:label id="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearTwo_documentation_en-US" xlink:label="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearTwo" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of non-vested shares that are scheduled to vest in year two.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearTwo" xlink:href="opi-20251231.xsd#opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearTwo"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearTwo" xlink:to="lab_opi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedSharesScheduledToVestInYearTwo" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A14672LeeRoadChantillyVAMember_019dbc7a-b1cb-7696-8d66-0c3b2a50c9cc_terseLabel_en-US" xlink:label="lab_opi_A14672LeeRoadChantillyVAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">14672 Lee Road, Chantilly, VA</link:label>
    <link:label id="lab_opi_A14672LeeRoadChantillyVAMember_label_en-US" xlink:label="lab_opi_A14672LeeRoadChantillyVAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">14672 Lee Road, Chantilly, VA [Member]</link:label>
    <link:label id="lab_opi_A14672LeeRoadChantillyVAMember_documentation_en-US" xlink:label="lab_opi_A14672LeeRoadChantillyVAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">14672 Lee Road, Chantilly, VA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A14672LeeRoadChantillyVAMember" xlink:href="opi-20251231.xsd#opi_A14672LeeRoadChantillyVAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A14672LeeRoadChantillyVAMember" xlink:to="lab_opi_A14672LeeRoadChantillyVAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_stpr_CA_019dbc7a-b1cb-74fc-b554-2c920bd9c29e_terseLabel_en-US" xlink:label="lab_stpr_CA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">California</link:label>
    <link:label id="lab_stpr_CA_label_en-US" xlink:label="lab_stpr_CA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">CALIFORNIA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_CA" xlink:href="https://xbrl.sec.gov/stpr/2025/stpr-2025.xsd#stpr_CA"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_stpr_CA" xlink:to="lab_stpr_CA" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A100RedwoodShoresParkwayRedwoodCityCAMember_019dbc7a-b287-786e-ba80-6879054a7092_terseLabel_en-US" xlink:label="lab_opi_A100RedwoodShoresParkwayRedwoodCityCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">100 Redwood Shores Parkway, Redwood City, CA</link:label>
    <link:label id="lab_opi_A100RedwoodShoresParkwayRedwoodCityCAMember_label_en-US" xlink:label="lab_opi_A100RedwoodShoresParkwayRedwoodCityCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">100 Redwood Shores Parkway, Redwood City, CA [Member]</link:label>
    <link:label id="lab_opi_A100RedwoodShoresParkwayRedwoodCityCAMember_documentation_en-US" xlink:label="lab_opi_A100RedwoodShoresParkwayRedwoodCityCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">100 Redwood Shores Parkway, Redwood City, CA [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A100RedwoodShoresParkwayRedwoodCityCAMember" xlink:href="opi-20251231.xsd#opi_A100RedwoodShoresParkwayRedwoodCityCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A100RedwoodShoresParkwayRedwoodCityCAMember" xlink:to="lab_opi_A100RedwoodShoresParkwayRedwoodCityCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfCommonStock_019dbc8a-7792-7298-968a-01f04ad34727_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from issuance of common shares, net</link:label>
    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfCommonStock_label_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Issuance of Common Stock</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:to="lab_us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A7850Southwest6thCourtPlantationFLMember_019dbc7a-b286-7bfa-9487-2a45a5b0f9ba_terseLabel_en-US" xlink:label="lab_opi_A7850Southwest6thCourtPlantationFLMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">7850 Southwest 6th Court, Plantation, FL</link:label>
    <link:label id="lab_opi_A7850Southwest6thCourtPlantationFLMember_label_en-US" xlink:label="lab_opi_A7850Southwest6thCourtPlantationFLMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">7850 Southwest 6th Court, Plantation, FL [Member]</link:label>
    <link:label id="lab_opi_A7850Southwest6thCourtPlantationFLMember_documentation_en-US" xlink:label="lab_opi_A7850Southwest6thCourtPlantationFLMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">7850 Southwest 6th Court, Plantation, FL</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A7850Southwest6thCourtPlantationFLMember" xlink:href="opi-20251231.xsd#opi_A7850Southwest6thCourtPlantationFLMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A7850Southwest6thCourtPlantationFLMember" xlink:to="lab_opi_A7850Southwest6thCourtPlantationFLMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AllIndividualsMember_terseLabel_en-US" xlink:label="lab_ecd_AllIndividualsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">All Individuals</link:label>
    <link:label id="lab_ecd_AllIndividualsMember_label_en-US" xlink:label="lab_ecd_AllIndividualsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">All Individuals [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AllIndividualsMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AllIndividualsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="lab_ecd_AllIndividualsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongtermDebtTypeDomain_019dbc7a-b287-73ec-9421-23d8f412adf4_terseLabel_en-US" xlink:label="lab_us-gaap_LongtermDebtTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Long-term Debt, Type [Domain]</link:label>
    <link:label id="lab_us-gaap_LongtermDebtTypeDomain_label_en-US" xlink:label="lab_us-gaap_LongtermDebtTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Type [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongtermDebtTypeDomain" xlink:to="lab_us-gaap_LongtermDebtTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueDisclosuresAbstract_019dbc7a-b286-7422-8e46-f997307b7b4f_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueDisclosuresAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair Value Disclosures [Abstract]</link:label>
    <link:label id="lab_us-gaap_FairValueDisclosuresAbstract_label_en-US" xlink:label="lab_us-gaap_FairValueDisclosuresAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value Disclosures [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueDisclosuresAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueDisclosuresAbstract" xlink:to="lab_us-gaap_FairValueDisclosuresAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A15451North28thAvenuePhoenixAZMember_019dbc7a-b1cb-7160-92e2-c91086153d1c_terseLabel_en-US" xlink:label="lab_opi_A15451North28thAvenuePhoenixAZMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">15451 North 28th Avenue, Phoenix, AZ</link:label>
    <link:label id="lab_opi_A15451North28thAvenuePhoenixAZMember_label_en-US" xlink:label="lab_opi_A15451North28thAvenuePhoenixAZMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">15451 North 28th Avenue, Phoenix, AZ [Member]</link:label>
    <link:label id="lab_opi_A15451North28thAvenuePhoenixAZMember_documentation_en-US" xlink:label="lab_opi_A15451North28thAvenuePhoenixAZMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">15451 North 28th Avenue, Phoenix, AZ</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A15451North28thAvenuePhoenixAZMember" xlink:href="opi-20251231.xsd#opi_A15451North28thAvenuePhoenixAZMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A15451North28thAvenuePhoenixAZMember" xlink:to="lab_opi_A15451North28thAvenuePhoenixAZMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_ForgoneRecoveryIndName_terseLabel_en-US" xlink:label="lab_ecd_ForgoneRecoveryIndName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Name</link:label>
    <link:label id="lab_ecd_ForgoneRecoveryIndName_label_en-US" xlink:label="lab_ecd_ForgoneRecoveryIndName" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Forgone Recovery, Individual Name</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_ForgoneRecoveryIndName" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_ForgoneRecoveryIndName"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_ForgoneRecoveryIndName" xlink:to="lab_ecd_ForgoneRecoveryIndName" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InterestPaidCapitalized_019dbc8e-47a3-7176-93d0-aa1ca73c0bc2_terseLabel_en-US" xlink:label="lab_us-gaap_InterestPaidCapitalized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Capitalized interest</link:label>
    <link:label id="lab_us-gaap_InterestPaidCapitalized_label_en-US" xlink:label="lab_us-gaap_InterestPaidCapitalized" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Paid, Capitalized, Investing Activity</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPaidCapitalized" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestPaidCapitalized"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestPaidCapitalized" xlink:to="lab_us-gaap_InterestPaidCapitalized" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_ChngInFrValOfOutsdngAndUnvstdEqtyAwrdsGrntdInPrrYrsMember_terseLabel_en-US" xlink:label="lab_ecd_ChngInFrValOfOutsdngAndUnvstdEqtyAwrdsGrntdInPrrYrsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested</link:label>
    <link:label id="lab_ecd_ChngInFrValOfOutsdngAndUnvstdEqtyAwrdsGrntdInPrrYrsMember_label_en-US" xlink:label="lab_ecd_ChngInFrValOfOutsdngAndUnvstdEqtyAwrdsGrntdInPrrYrsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_ChngInFrValOfOutsdngAndUnvstdEqtyAwrdsGrntdInPrrYrsMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_ChngInFrValOfOutsdngAndUnvstdEqtyAwrdsGrntdInPrrYrsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_ChngInFrValOfOutsdngAndUnvstdEqtyAwrdsGrntdInPrrYrsMember" xlink:to="lab_ecd_ChngInFrValOfOutsdngAndUnvstdEqtyAwrdsGrntdInPrrYrsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableNextTwelveMonths_019dbc7a-b287-7556-b52d-f6c322631da8_terseLabel_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2026</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableNextTwelveMonths_label_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right, Exercisable Next Twelve Months</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableNextTwelveMonths_documentation_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right, Exercisable Next Twelve Months</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableNextTwelveMonths" xlink:href="opi-20251231.xsd#opi_ConcentrationRiskPercentageForTerminationRightExercisableNextTwelveMonths"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableNextTwelveMonths" xlink:to="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableNextTwelveMonths" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A9.000SeniorSecuredNotesPayableDueInSeptember2029Member_019dbc7a-b1cb-79e0-b748-cb0e06498c07_terseLabel_en-US" xlink:label="lab_opi_A9.000SeniorSecuredNotesPayableDueInSeptember2029Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior secured notes, 9.000% interest rate, due in September 2029</link:label>
    <link:label id="lab_opi_A9.000SeniorSecuredNotesPayableDueInSeptember2029Member_label_en-US" xlink:label="lab_opi_A9.000SeniorSecuredNotesPayableDueInSeptember2029Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">9.000% Senior Secured Notes Payable, Due In September 2029 [Member]</link:label>
    <link:label id="lab_opi_A9.000SeniorSecuredNotesPayableDueInSeptember2029Member_documentation_en-US" xlink:label="lab_opi_A9.000SeniorSecuredNotesPayableDueInSeptember2029Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">9.000% Senior Secured Notes Payable, Due In September 2029</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A9.000SeniorSecuredNotesPayableDueInSeptember2029Member" xlink:href="opi-20251231.xsd#opi_A9.000SeniorSecuredNotesPayableDueInSeptember2029Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A9.000SeniorSecuredNotesPayableDueInSeptember2029Member" xlink:to="lab_opi_A9.000SeniorSecuredNotesPayableDueInSeptember2029Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DisposalGroupClassificationAxis_019dbc7a-b287-731b-8a3f-806225d0a4f2_terseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupClassificationAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Disposal Group Classification [Axis]</link:label>
    <link:label id="lab_us-gaap_DisposalGroupClassificationAxis_label_en-US" xlink:label="lab_us-gaap_DisposalGroupClassificationAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group Classification [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis" xlink:to="lab_us-gaap_DisposalGroupClassificationAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SecuredRevolvingCreditFacilityMember_019dbcaa-b0b7-7223-8a7d-946d3b9c6ce0_terseLabel_en-US" xlink:label="lab_opi_SecuredRevolvingCreditFacilityMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Secured revolving credit facility, due in 2027</link:label>
    <link:label id="lab_opi_SecuredRevolvingCreditFacilityMember_label_en-US" xlink:label="lab_opi_SecuredRevolvingCreditFacilityMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Secured Revolving Credit Facility [Member]</link:label>
    <link:label id="lab_opi_SecuredRevolvingCreditFacilityMember_documentation_en-US" xlink:label="lab_opi_SecuredRevolvingCreditFacilityMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Secured Revolving Credit Facility</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SecuredRevolvingCreditFacilityMember" xlink:href="opi-20251231.xsd#opi_SecuredRevolvingCreditFacilityMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SecuredRevolvingCreditFacilityMember" xlink:to="lab_opi_SecuredRevolvingCreditFacilityMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ReorganizationItemsPolicyPolicyTextBlock_019dd0b5-5b8d-7d4d-a41d-a2f0d9404962_terseLabel_en-US" xlink:label="lab_opi_ReorganizationItemsPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reorganization items, net</link:label>
    <link:label id="lab_opi_ReorganizationItemsPolicyPolicyTextBlock_label_en-US" xlink:label="lab_opi_ReorganizationItemsPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reorganization Items, Policy [Policy Text Block]</link:label>
    <link:label id="lab_opi_ReorganizationItemsPolicyPolicyTextBlock_documentation_en-US" xlink:label="lab_opi_ReorganizationItemsPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Reorganization Items, Policy</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ReorganizationItemsPolicyPolicyTextBlock" xlink:href="opi-20251231.xsd#opi_ReorganizationItemsPolicyPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ReorganizationItemsPolicyPolicyTextBlock" xlink:to="lab_opi_ReorganizationItemsPolicyPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GainLossOnSaleOfProperties_019dbc7a-b1cb-7720-9b09-977ea26251b1_terseLabel_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfProperties" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gain (loss) on sale of real estate</link:label>
    <link:label id="lab_us-gaap_GainLossOnSaleOfProperties_019dbc86-2ac5-779c-b3e7-3c418d4f965a_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfProperties" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">(Gain) loss on sale of real estate</link:label>
    <link:label id="lab_us-gaap_GainLossOnSaleOfProperties_019dbc7a-b1cb-78e0-81ed-2b5325c4b2fa_verboseLabel_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfProperties" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Gain (Loss) on Sale of Real Estate</link:label>
    <link:label id="lab_us-gaap_GainLossOnSaleOfProperties_019dd08c-a740-754e-84b5-e3d3901ae308_negatedLabel_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfProperties" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Gain on sale of real estate</link:label>
    <link:label id="lab_us-gaap_GainLossOnSaleOfProperties_label_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfProperties" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gain (Loss) on Sale of Properties</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfProperties" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnSaleOfProperties"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GainLossOnSaleOfProperties" xlink:to="lab_us-gaap_GainLossOnSaleOfProperties" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_ErrCompAnalysisTextBlock_terseLabel_en-US" xlink:label="lab_ecd_ErrCompAnalysisTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Erroneous Compensation Analysis</link:label>
    <link:label id="lab_ecd_ErrCompAnalysisTextBlock_label_en-US" xlink:label="lab_ecd_ErrCompAnalysisTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Erroneous Compensation Analysis [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_ErrCompAnalysisTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_ErrCompAnalysisTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_ErrCompAnalysisTextBlock" xlink:to="lab_ecd_ErrCompAnalysisTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_StatementGeographicalAxis_019dbc7a-b1cb-7eaa-8548-8b9c184293b0_terseLabel_en-US" xlink:label="lab_srt_StatementGeographicalAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Geographical [Axis]</link:label>
    <link:label id="lab_srt_StatementGeographicalAxis_label_en-US" xlink:label="lab_srt_StatementGeographicalAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Geographical [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_StatementGeographicalAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_StatementGeographicalAxis" xlink:to="lab_srt_StatementGeographicalAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LiabilitiesHeldForSaleProperty_019dbc7a-b287-7605-88f4-06ae21af8ab9_terseLabel_en-US" xlink:label="lab_opi_LiabilitiesHeldForSaleProperty" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Liabilities of properties held for sale</link:label>
    <link:label id="lab_opi_LiabilitiesHeldForSaleProperty_label_en-US" xlink:label="lab_opi_LiabilitiesHeldForSaleProperty" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities Held For Sale Property</link:label>
    <link:label id="lab_opi_LiabilitiesHeldForSaleProperty_documentation_en-US" xlink:label="lab_opi_LiabilitiesHeldForSaleProperty" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amount classified as liabilities attributable to property that is held for sale apart from normal operations and anticipated to be sold in less than one year.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LiabilitiesHeldForSaleProperty" xlink:href="opi-20251231.xsd#opi_LiabilitiesHeldForSaleProperty"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LiabilitiesHeldForSaleProperty" xlink:to="lab_opi_LiabilitiesHeldForSaleProperty" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeLeaseDescriptionLineItems_019dbc7a-b286-7ec3-a880-82fcd0de6527_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeLeaseDescriptionLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lessee, Lease, Description [Line Items]</link:label>
    <link:label id="lab_us-gaap_LesseeLeaseDescriptionLineItems_label_en-US" xlink:label="lab_us-gaap_LesseeLeaseDescriptionLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Lease, Description [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems" xlink:to="lab_us-gaap_LesseeLeaseDescriptionLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_TransactionTypeAxis_019dbc7a-b1cb-73c4-ac1f-753b37b2e741_terseLabel_en-US" xlink:label="lab_us-gaap_TransactionTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Transaction Type [Axis]</link:label>
    <link:label id="lab_us-gaap_TransactionTypeAxis_label_en-US" xlink:label="lab_us-gaap_TransactionTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Transaction Type [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransactionTypeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TransactionTypeAxis" xlink:to="lab_us-gaap_TransactionTypeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_Rule10b51ArrTrmntdFlag_terseLabel_en-US" xlink:label="lab_ecd_Rule10b51ArrTrmntdFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rule 10b5-1 Arrangement Terminated</link:label>
    <link:label id="lab_ecd_Rule10b51ArrTrmntdFlag_label_en-US" xlink:label="lab_ecd_Rule10b51ArrTrmntdFlag" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Rule 10b5-1 Arrangement Terminated [Flag]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_Rule10b51ArrTrmntdFlag" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_Rule10b51ArrTrmntdFlag"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_Rule10b51ArrTrmntdFlag" xlink:to="lab_ecd_Rule10b51ArrTrmntdFlag" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLeasesOfLessorDisclosureTextBlock_019dbc7a-b1cb-77ff-953c-9ed09f3bec4d_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesOfLessorDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Leases</link:label>
    <link:label id="lab_us-gaap_OperatingLeasesOfLessorDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_OperatingLeasesOfLessorDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Leases [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasesOfLessorDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeasesOfLessorDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeasesOfLessorDisclosureTextBlock" xlink:to="lab_us-gaap_OperatingLeasesOfLessorDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic_019dbc7a-b1cb-72a4-92ae-687f9823e95f_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Income attributable to unvested participating securities</link:label>
    <link:label id="lab_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic_label_en-US" xlink:label="lab_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Participating Securities, Distributed and Undistributed Earnings (Loss), Basic</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic" xlink:to="lab_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_ErrCompRecoveryTable_terseLabel_en-US" xlink:label="lab_ecd_ErrCompRecoveryTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Erroneously Awarded Compensation Recovery</link:label>
    <link:label id="lab_ecd_ErrCompRecoveryTable_label_en-US" xlink:label="lab_ecd_ErrCompRecoveryTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Erroneously Awarded Compensation Recovery [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_ErrCompRecoveryTable" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_ErrCompRecoveryTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_ErrCompRecoveryTable" xlink:to="lab_ecd_ErrCompRecoveryTable" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_UnisonElliottBayOfficeSpaceSeattleWAMember_019dbc7a-b286-722e-984d-944e70c76ac9_terseLabel_en-US" xlink:label="lab_opi_UnisonElliottBayOfficeSpaceSeattleWAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unison Elliott Bay-Office Space, Seattle, WA</link:label>
    <link:label id="lab_opi_UnisonElliottBayOfficeSpaceSeattleWAMember_label_en-US" xlink:label="lab_opi_UnisonElliottBayOfficeSpaceSeattleWAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Unison Elliott Bay-Office Space, Seattle, WA [Member]</link:label>
    <link:label id="lab_opi_UnisonElliottBayOfficeSpaceSeattleWAMember_documentation_en-US" xlink:label="lab_opi_UnisonElliottBayOfficeSpaceSeattleWAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Unison Elliott Bay-Office Space, Seattle, WA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_UnisonElliottBayOfficeSpaceSeattleWAMember" xlink:href="opi-20251231.xsd#opi_UnisonElliottBayOfficeSpaceSeattleWAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_UnisonElliottBayOfficeSpaceSeattleWAMember" xlink:to="lab_opi_UnisonElliottBayOfficeSpaceSeattleWAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ConcentrationRiskBenchmarkDomain_019dbc7a-b1cb-764b-9b83-258d907a9821_terseLabel_en-US" xlink:label="lab_us-gaap_ConcentrationRiskBenchmarkDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Concentration Risk Benchmark [Domain]</link:label>
    <link:label id="lab_us-gaap_ConcentrationRiskBenchmarkDomain_label_en-US" xlink:label="lab_us-gaap_ConcentrationRiskBenchmarkDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Benchmark [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain" xlink:to="lab_us-gaap_ConcentrationRiskBenchmarkDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeLeaseDescriptionTable_019dbc7a-b287-783f-9fff-d2a767740f8c_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeLeaseDescriptionTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lessee, Lease, Description [Table]</link:label>
    <link:label id="lab_us-gaap_LesseeLeaseDescriptionTable_label_en-US" xlink:label="lab_us-gaap_LesseeLeaseDescriptionTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Lease, Description [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable" xlink:to="lab_us-gaap_LesseeLeaseDescriptionTable" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_AccountingPoliciesLineItems_019e2c1a-79ea-7d90-ad4c-47499876d3b7_terseLabel_en-US" xlink:label="lab_opi_AccountingPoliciesLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounting Policies [Line Items]</link:label>
    <link:label id="lab_opi_AccountingPoliciesLineItems_label_en-US" xlink:label="lab_opi_AccountingPoliciesLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounting Policies [Line Items]</link:label>
    <link:label id="lab_opi_AccountingPoliciesLineItems_documentation_en-US" xlink:label="lab_opi_AccountingPoliciesLineItems" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Accounting Policies [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_AccountingPoliciesLineItems" xlink:href="opi-20251231.xsd#opi_AccountingPoliciesLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_AccountingPoliciesLineItems" xlink:to="lab_opi_AccountingPoliciesLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_FolsomCorporateCenterFolsomCAMember_019dbc7a-b1cb-7b4f-b7f5-013965483e21_terseLabel_en-US" xlink:label="lab_opi_FolsomCorporateCenterFolsomCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Folsom Corporate Center, Folsom, CA</link:label>
    <link:label id="lab_opi_FolsomCorporateCenterFolsomCAMember_label_en-US" xlink:label="lab_opi_FolsomCorporateCenterFolsomCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Folsom Corporate Center, Folsom, CA [Member]</link:label>
    <link:label id="lab_opi_FolsomCorporateCenterFolsomCAMember_documentation_en-US" xlink:label="lab_opi_FolsomCorporateCenterFolsomCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Folsom Corporate Center, Folsom, CA [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_FolsomCorporateCenterFolsomCAMember" xlink:href="opi-20251231.xsd#opi_FolsomCorporateCenterFolsomCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_FolsomCorporateCenterFolsomCAMember" xlink:to="lab_opi_FolsomCorporateCenterFolsomCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EarningsPerShareAbstract_019dbc7a-b287-7915-a649-e8438508fdf6_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Per common share amounts (basic and diluted):</link:label>
    <link:label id="lab_us-gaap_EarningsPerShareAbstract_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Earnings Per Share [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareAbstract" xlink:to="lab_us-gaap_EarningsPerShareAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ATMOfferingMember_019dd0dc-686b-7bdb-b09c-5e353fee0ef1_terseLabel_en-US" xlink:label="lab_opi_ATMOfferingMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">ATM Offering</link:label>
    <link:label id="lab_opi_ATMOfferingMember_label_en-US" xlink:label="lab_opi_ATMOfferingMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">ATM Offering [Member]</link:label>
    <link:label id="lab_opi_ATMOfferingMember_documentation_en-US" xlink:label="lab_opi_ATMOfferingMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">ATM Offering</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ATMOfferingMember" xlink:href="opi-20251231.xsd#opi_ATMOfferingMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ATMOfferingMember" xlink:to="lab_opi_ATMOfferingMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_NumberOfAgreements_019dbc7a-b1cb-75c7-a231-2a8852c0dbe5_terseLabel_en-US" xlink:label="lab_opi_NumberOfAgreements" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of agreements with RMR LLC to provide management services</link:label>
    <link:label id="lab_opi_NumberOfAgreements_label_en-US" xlink:label="lab_opi_NumberOfAgreements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number Of Agreements</link:label>
    <link:label id="lab_opi_NumberOfAgreements_documentation_en-US" xlink:label="lab_opi_NumberOfAgreements" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of agreements with RMR LLC to provide management services to the company.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_NumberOfAgreements" xlink:href="opi-20251231.xsd#opi_NumberOfAgreements"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_NumberOfAgreements" xlink:to="lab_opi_NumberOfAgreements" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A9201ForestHillAvenueRichmondVAMember_019dbc7a-b286-720a-b247-16f668b4234d_terseLabel_en-US" xlink:label="lab_opi_A9201ForestHillAvenueRichmondVAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">9201 Forest Hill Avenue, Richmond, VA</link:label>
    <link:label id="lab_opi_A9201ForestHillAvenueRichmondVAMember_label_en-US" xlink:label="lab_opi_A9201ForestHillAvenueRichmondVAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">9201 Forest Hill Avenue, Richmond, VA [Member]</link:label>
    <link:label id="lab_opi_A9201ForestHillAvenueRichmondVAMember_documentation_en-US" xlink:label="lab_opi_A9201ForestHillAvenueRichmondVAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">9201 Forest Hill avenue [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A9201ForestHillAvenueRichmondVAMember" xlink:href="opi-20251231.xsd#opi_A9201ForestHillAvenueRichmondVAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A9201ForestHillAvenueRichmondVAMember" xlink:to="lab_opi_A9201ForestHillAvenueRichmondVAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_CommonStockDividendsReturnOfCapitalDistributionPercentage_019dbc7a-b287-7801-8b87-b5140cf52ff4_verboseLabel_en-US" xlink:label="lab_opi_CommonStockDividendsReturnOfCapitalDistributionPercentage" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Characterization of Distribution, Return of Capital</link:label>
    <link:label id="lab_opi_CommonStockDividendsReturnOfCapitalDistributionPercentage_label_en-US" xlink:label="lab_opi_CommonStockDividendsReturnOfCapitalDistributionPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock Dividends Return Of Capital Distribution Percentage</link:label>
    <link:label id="lab_opi_CommonStockDividendsReturnOfCapitalDistributionPercentage_documentation_en-US" xlink:label="lab_opi_CommonStockDividendsReturnOfCapitalDistributionPercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Common Stock Dividends Return Of Capital Distribution Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_CommonStockDividendsReturnOfCapitalDistributionPercentage" xlink:href="opi-20251231.xsd#opi_CommonStockDividendsReturnOfCapitalDistributionPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_CommonStockDividendsReturnOfCapitalDistributionPercentage" xlink:to="lab_opi_CommonStockDividendsReturnOfCapitalDistributionPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualPercentageIncrease_019dbc7a-b286-72be-8cb3-f4830b49014a_terseLabel_en-US" xlink:label="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualPercentageIncrease" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Annual percentage increase</link:label>
    <link:label id="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualPercentageIncrease_label_en-US" xlink:label="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualPercentageIncrease" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Lease Not yet Commenced, Annual Percentage Increase</link:label>
    <link:label id="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualPercentageIncrease_documentation_en-US" xlink:label="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualPercentageIncrease" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Lease Not yet Commenced, Annual Percentage Increase</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualPercentageIncrease" xlink:href="opi-20251231.xsd#opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualPercentageIncrease"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualPercentageIncrease" xlink:to="lab_opi_LessorOperatingLeaseLeaseNotYetCommencedAnnualPercentageIncrease" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReorganizationItems_019dd096-e859-70ab-9ed7-5cec048bf67e_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_ReorganizationItems" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Reorganization items, net</link:label>
    <link:label id="lab_us-gaap_ReorganizationItems_019dd0c0-b7d5-7b57-93a8-9f914eab16ec_totalLabel_en-US" xlink:label="lab_us-gaap_ReorganizationItems" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total reorganization items, net</link:label>
    <link:label id="lab_us-gaap_ReorganizationItems_label_en-US" xlink:label="lab_us-gaap_ReorganizationItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reorganization Items</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReorganizationItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReorganizationItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReorganizationItems" xlink:to="lab_us-gaap_ReorganizationItems" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DebtInstrumentVoluntaryPrepaymentFeePercentage_019dd61f-ace1-76dc-a9f4-09d457f933c2_terseLabel_en-US" xlink:label="lab_opi_DebtInstrumentVoluntaryPrepaymentFeePercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash Prepayment premium as a percentage for voluntary prepayment</link:label>
    <link:label id="lab_opi_DebtInstrumentVoluntaryPrepaymentFeePercentage_label_en-US" xlink:label="lab_opi_DebtInstrumentVoluntaryPrepaymentFeePercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Voluntary Prepayment Fee Percentage</link:label>
    <link:label id="lab_opi_DebtInstrumentVoluntaryPrepaymentFeePercentage_documentation_en-US" xlink:label="lab_opi_DebtInstrumentVoluntaryPrepaymentFeePercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Voluntary Prepayment Fee Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DebtInstrumentVoluntaryPrepaymentFeePercentage" xlink:href="opi-20251231.xsd#opi_DebtInstrumentVoluntaryPrepaymentFeePercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DebtInstrumentVoluntaryPrepaymentFeePercentage" xlink:to="lab_opi_DebtInstrumentVoluntaryPrepaymentFeePercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThirteen_019dbc7a-b1cb-70cd-ade8-599c9dc38d87_terseLabel_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThirteen" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2040</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThirteen_label_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThirteen" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right Exercisable In Year Thirteen</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThirteen_documentation_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThirteen" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right Exercisable In Year Thirteen</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThirteen" xlink:href="opi-20251231.xsd#opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThirteen"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThirteen" xlink:to="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThirteen" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_KansasCityMOMember_019dbc7a-b1cb-7ab8-b7ca-d6ca8a8683de_terseLabel_en-US" xlink:label="lab_opi_KansasCityMOMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Kansas City, MO</link:label>
    <link:label id="lab_opi_KansasCityMOMember_label_en-US" xlink:label="lab_opi_KansasCityMOMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Kansas City, MO [Member]</link:label>
    <link:label id="lab_opi_KansasCityMOMember_documentation_en-US" xlink:label="lab_opi_KansasCityMOMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Kansas City, MO</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_KansasCityMOMember" xlink:href="opi-20251231.xsd#opi_KansasCityMOMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_KansasCityMOMember" xlink:to="lab_opi_KansasCityMOMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AwardTmgDiscLineItems_label_en-US" xlink:label="lab_ecd_AwardTmgDiscLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Award Timing Disclosures [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AwardTmgDiscLineItems" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AwardTmgDiscLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AwardTmgDiscLineItems" xlink:to="lab_ecd_AwardTmgDiscLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A7001ColumbiaGatewayDriveColumbiaMDMember_019dbc7a-b287-7b28-ba5f-5ca01e46d7ca_terseLabel_en-US" xlink:label="lab_opi_A7001ColumbiaGatewayDriveColumbiaMDMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">7001 Columbia Gateway Drive, Columbia, MD</link:label>
    <link:label id="lab_opi_A7001ColumbiaGatewayDriveColumbiaMDMember_label_en-US" xlink:label="lab_opi_A7001ColumbiaGatewayDriveColumbiaMDMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">7001 Columbia Gateway Drive, Columbia, MD [Member]</link:label>
    <link:label id="lab_opi_A7001ColumbiaGatewayDriveColumbiaMDMember_documentation_en-US" xlink:label="lab_opi_A7001ColumbiaGatewayDriveColumbiaMDMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">7001 Columbia Gateway Drive, Columbia, MD [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A7001ColumbiaGatewayDriveColumbiaMDMember" xlink:href="opi-20251231.xsd#opi_A7001ColumbiaGatewayDriveColumbiaMDMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A7001ColumbiaGatewayDriveColumbiaMDMember" xlink:to="lab_opi_A7001ColumbiaGatewayDriveColumbiaMDMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtorReorganizationItemsWriteOffOfDeferredFinancingCostsAndDebtDiscounts_019dd0c0-94aa-7471-a3f8-739d877c8ee1_terseLabel_en-US" xlink:label="lab_us-gaap_DebtorReorganizationItemsWriteOffOfDeferredFinancingCostsAndDebtDiscounts" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt issuance costs</link:label>
    <link:label id="lab_us-gaap_DebtorReorganizationItemsWriteOffOfDeferredFinancingCostsAndDebtDiscounts_label_en-US" xlink:label="lab_us-gaap_DebtorReorganizationItemsWriteOffOfDeferredFinancingCostsAndDebtDiscounts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debtor Reorganization Items, Debt Issuance Cost and Debt Discount, Writeoff</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtorReorganizationItemsWriteOffOfDeferredFinancingCostsAndDebtDiscounts" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtorReorganizationItemsWriteOffOfDeferredFinancingCostsAndDebtDiscounts"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtorReorganizationItemsWriteOffOfDeferredFinancingCostsAndDebtDiscounts" xlink:to="lab_us-gaap_DebtorReorganizationItemsWriteOffOfDeferredFinancingCostsAndDebtDiscounts" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A10.00SeniorSecuredNotesPayableDueIn2031Member_019dff13-dada-7051-9d7a-e1ad3bc7ae17_terseLabel_en-US" xlink:label="lab_opi_A10.00SeniorSecuredNotesPayableDueIn2031Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Secured Exit Notes</link:label>
    <link:label id="lab_opi_A10.00SeniorSecuredNotesPayableDueIn2031Member_label_en-US" xlink:label="lab_opi_A10.00SeniorSecuredNotesPayableDueIn2031Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">10.00% Senior Secured Notes Payable, Due In 2031 [Member]</link:label>
    <link:label id="lab_opi_A10.00SeniorSecuredNotesPayableDueIn2031Member_documentation_en-US" xlink:label="lab_opi_A10.00SeniorSecuredNotesPayableDueIn2031Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">10.00% Senior Secured Notes Payable, Due In 2031</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A10.00SeniorSecuredNotesPayableDueIn2031Member" xlink:href="opi-20251231.xsd#opi_A10.00SeniorSecuredNotesPayableDueIn2031Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A10.00SeniorSecuredNotesPayableDueIn2031Member" xlink:to="lab_opi_A10.00SeniorSecuredNotesPayableDueIn2031Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroup_019dbc7a-b1cb-78a1-b681-3084b1cceab9_verboseLabel_en-US" xlink:label="lab_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroup" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Assets of properties held for sale</link:label>
    <link:label id="lab_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroup_label_en-US" xlink:label="lab_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroup" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Asset, Held-for-Sale, Not Part of Disposal Group</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroup" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsHeldForSaleNotPartOfDisposalGroup"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroup" xlink:to="lab_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroup" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockholdersEquityNoteDisclosureTextBlock_019dbc7a-b1cb-77fb-98ca-d1b99dc55b57_terseLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Shareholders' Equity</link:label>
    <link:label id="lab_us-gaap_StockholdersEquityNoteDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityNoteDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:to="lab_us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_stpr_IL_019dbc7a-b1cb-7c7a-a360-a0254d23fce3_terseLabel_en-US" xlink:label="lab_stpr_IL" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Illinois</link:label>
    <link:label id="lab_stpr_IL_label_en-US" xlink:label="lab_stpr_IL" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">ILLINOIS</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_IL" xlink:href="https://xbrl.sec.gov/stpr/2025/stpr-2025.xsd#stpr_IL"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_stpr_IL" xlink:to="lab_stpr_IL" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetIncomeLoss_019dbc7f-2a8d-7034-8eb7-9ce4f7d97bef_totalLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net loss</link:label>
    <link:label id="lab_us-gaap_NetIncomeLoss_019dbc82-4a7f-75cf-a2d8-5f5b44911dbe_verboseLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Net loss</link:label>
    <link:label id="lab_us-gaap_NetIncomeLoss_019dd086-b1c0-7ad1-a84b-673bc5f4b460_terseLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net Income (Loss)</link:label>
    <link:label id="lab_us-gaap_NetIncomeLoss_label_en-US" xlink:label="lab_us-gaap_NetIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Income (Loss) Attributable to Parent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetIncomeLoss" xlink:to="lab_us-gaap_NetIncomeLoss" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThree_019dbc7a-b286-765b-ab20-74399bbd3fd0_terseLabel_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2028</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThree_label_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Percentage For Termination Right, Exercisable In Year Three</link:label>
    <link:label id="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThree_documentation_en-US" xlink:label="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThree" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the percentage as a concentration risk for termination right exercisable in year three from the balance sheet date.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThree" xlink:href="opi-20251231.xsd#opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThree"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThree" xlink:to="lab_opi_ConcentrationRiskPercentageForTerminationRightExercisableInYearThree" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionPerformanceYearsTerminationThreshold_019dbc7a-b286-7ee2-901f-6bfaa5bd72c4_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionPerformanceYearsTerminationThreshold" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Performance years termination threshold</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionPerformanceYearsTerminationThreshold_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionPerformanceYearsTerminationThreshold" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Performance Years Termination Threshold</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionPerformanceYearsTerminationThreshold_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionPerformanceYearsTerminationThreshold" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Related Party Transaction, Performance Years Termination Threshold</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionPerformanceYearsTerminationThreshold" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionPerformanceYearsTerminationThreshold"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionPerformanceYearsTerminationThreshold" xlink:to="lab_opi_RelatedPartyTransactionPerformanceYearsTerminationThreshold" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A202NorthCastlegoryRoadHoustonTXMember_019dbc7a-b1cb-73e4-b4f6-0f283481c36c_terseLabel_en-US" xlink:label="lab_opi_A202NorthCastlegoryRoadHoustonTXMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">202 North Castlegory Road, Houston, TX</link:label>
    <link:label id="lab_opi_A202NorthCastlegoryRoadHoustonTXMember_label_en-US" xlink:label="lab_opi_A202NorthCastlegoryRoadHoustonTXMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">202 North Castlegory Road, Houston, TX [Member]</link:label>
    <link:label id="lab_opi_A202NorthCastlegoryRoadHoustonTXMember_documentation_en-US" xlink:label="lab_opi_A202NorthCastlegoryRoadHoustonTXMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">202 North Castlegory Road, Houston, TX [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A202NorthCastlegoryRoadHoustonTXMember" xlink:href="opi-20251231.xsd#opi_A202NorthCastlegoryRoadHoustonTXMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A202NorthCastlegoryRoadHoustonTXMember" xlink:to="lab_opi_A202NorthCastlegoryRoadHoustonTXMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateInvestmentPropertyNet_019dbc7a-b1cb-7ad1-93fb-25df7aab5709_totalLabel_en-US" xlink:label="lab_us-gaap_RealEstateInvestmentPropertyNet" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total real estate properties, net</link:label>
    <link:label id="lab_us-gaap_RealEstateInvestmentPropertyNet_label_en-US" xlink:label="lab_us-gaap_RealEstateInvestmentPropertyNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Investment Property, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateInvestmentPropertyNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateInvestmentPropertyNet" xlink:to="lab_us-gaap_RealEstateInvestmentPropertyNet" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateGrossAtCarryingValue_019dbc7a-b287-71e8-8569-d543c41a783b_totalLabel_en-US" xlink:label="lab_us-gaap_RealEstateGrossAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total</link:label>
    <link:label id="lab_us-gaap_RealEstateGrossAtCarryingValue_019dbc7a-b287-7bdb-bee5-feec7456ccd2_periodStartLabel_en-US" xlink:label="lab_us-gaap_RealEstateGrossAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Balance at the beginning of the period</link:label>
    <link:label id="lab_us-gaap_RealEstateGrossAtCarryingValue_019dbc7a-b287-78ff-9014-4b07839f7b82_periodEndLabel_en-US" xlink:label="lab_us-gaap_RealEstateGrossAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Balance at the end of the period</link:label>
    <link:label id="lab_us-gaap_RealEstateGrossAtCarryingValue_label_en-US" xlink:label="lab_us-gaap_RealEstateGrossAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateGrossAtCarryingValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateGrossAtCarryingValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateGrossAtCarryingValue" xlink:to="lab_us-gaap_RealEstateGrossAtCarryingValue" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_StockRepurchasedDuringPeriodPricePerShare_019dbc7a-b287-7ffb-88f5-ed27d8711fee_terseLabel_en-US" xlink:label="lab_opi_StockRepurchasedDuringPeriodPricePerShare" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stock repurchase price (in dollars per share)</link:label>
    <link:label id="lab_opi_StockRepurchasedDuringPeriodPricePerShare_label_en-US" xlink:label="lab_opi_StockRepurchasedDuringPeriodPricePerShare" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Repurchased During Period, Price Per Share</link:label>
    <link:label id="lab_opi_StockRepurchasedDuringPeriodPricePerShare_documentation_en-US" xlink:label="lab_opi_StockRepurchasedDuringPeriodPricePerShare" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Stock Repurchased During Period, Price Per Share</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_StockRepurchasedDuringPeriodPricePerShare" xlink:href="opi-20251231.xsd#opi_StockRepurchasedDuringPeriodPricePerShare"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_StockRepurchasedDuringPeriodPricePerShare" xlink:to="lab_opi_StockRepurchasedDuringPeriodPricePerShare" xlink:type="arc" order="1"/>
    <link:label id="lab_stpr_GA_019dbca8-24c7-70e5-aa08-7974a2d6a573_terseLabel_en-US" xlink:label="lab_stpr_GA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Georgia</link:label>
    <link:label id="lab_stpr_GA_label_en-US" xlink:label="lab_stpr_GA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">GEORGIA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_GA" xlink:href="https://xbrl.sec.gov/stpr/2025/stpr-2025.xsd#stpr_GA"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_stpr_GA" xlink:to="lab_stpr_GA" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RealEstateAndAccumulatedDepreciationBuildingsAndImprovementsLifeUsedForDepreciation_019dbc7a-b1cb-71fd-b324-d08ec8ae3a10_terseLabel_en-US" xlink:label="lab_opi_RealEstateAndAccumulatedDepreciationBuildingsAndImprovementsLifeUsedForDepreciation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Useful life of buildings and improvements</link:label>
    <link:label id="lab_opi_RealEstateAndAccumulatedDepreciationBuildingsAndImprovementsLifeUsedForDepreciation_label_en-US" xlink:label="lab_opi_RealEstateAndAccumulatedDepreciationBuildingsAndImprovementsLifeUsedForDepreciation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate and Accumulated Depreciation Buildings and Improvements Life Used for Depreciation</link:label>
    <link:label id="lab_opi_RealEstateAndAccumulatedDepreciationBuildingsAndImprovementsLifeUsedForDepreciation_documentation_en-US" xlink:label="lab_opi_RealEstateAndAccumulatedDepreciationBuildingsAndImprovementsLifeUsedForDepreciation" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the estimated economic life of buildings and improvements on which depreciation in the latest income statement was computed.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RealEstateAndAccumulatedDepreciationBuildingsAndImprovementsLifeUsedForDepreciation" xlink:href="opi-20251231.xsd#opi_RealEstateAndAccumulatedDepreciationBuildingsAndImprovementsLifeUsedForDepreciation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RealEstateAndAccumulatedDepreciationBuildingsAndImprovementsLifeUsedForDepreciation" xlink:to="lab_opi_RealEstateAndAccumulatedDepreciationBuildingsAndImprovementsLifeUsedForDepreciation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_019dbc7a-b287-73b2-987d-70ffa67202c9_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Award vesting period</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DebtInstrumentCapitalCommitmentFeePercentage_019dd61d-bfee-7dcb-9fab-26367c676df3_terseLabel_en-US" xlink:label="lab_opi_DebtInstrumentCapitalCommitmentFeePercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Capital commitment fee as a percentage of lenders' commitments</link:label>
    <link:label id="lab_opi_DebtInstrumentCapitalCommitmentFeePercentage_label_en-US" xlink:label="lab_opi_DebtInstrumentCapitalCommitmentFeePercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Capital Commitment Fee Percentage</link:label>
    <link:label id="lab_opi_DebtInstrumentCapitalCommitmentFeePercentage_documentation_en-US" xlink:label="lab_opi_DebtInstrumentCapitalCommitmentFeePercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Capital Commitment Fee Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DebtInstrumentCapitalCommitmentFeePercentage" xlink:href="opi-20251231.xsd#opi_DebtInstrumentCapitalCommitmentFeePercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DebtInstrumentCapitalCommitmentFeePercentage" xlink:to="lab_opi_DebtInstrumentCapitalCommitmentFeePercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsForRepurchaseOfCommonStock_019dbc8d-51ce-7ce5-a579-05f20e4c913b_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Repurchases of common shares</link:label>
    <link:label id="lab_us-gaap_PaymentsForRepurchaseOfCommonStock_label_en-US" xlink:label="lab_us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments for Repurchase of Common Stock</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:to="lab_us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_TrdArrAdoptionDate_terseLabel_en-US" xlink:label="lab_ecd_TrdArrAdoptionDate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Adoption Date</link:label>
    <link:label id="lab_ecd_TrdArrAdoptionDate_label_en-US" xlink:label="lab_ecd_TrdArrAdoptionDate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Trading Arrangement Adoption Date</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_TrdArrAdoptionDate" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_TrdArrAdoptionDate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_TrdArrAdoptionDate" xlink:to="lab_ecd_TrdArrAdoptionDate" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A450SeniorUnsecuredNotesMember_019dbc7a-b286-7d1a-8652-18a22d89aedb_terseLabel_en-US" xlink:label="lab_opi_A450SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior unsecured notes, 4.500% interest rate, due in 2025</link:label>
    <link:label id="lab_opi_A450SeniorUnsecuredNotesMember_019dbc7a-b286-7cd5-bf42-8062abb0421f_verboseLabel_en-US" xlink:label="lab_opi_A450SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Existing 2.650% 2026 Notes</link:label>
    <link:label id="lab_opi_A450SeniorUnsecuredNotesMember_label_en-US" xlink:label="lab_opi_A450SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">4.50% Senior Unsecured Notes [Member]</link:label>
    <link:label id="lab_opi_A450SeniorUnsecuredNotesMember_documentation_en-US" xlink:label="lab_opi_A450SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">4.50% Senior Unsecured Notes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A450SeniorUnsecuredNotesMember" xlink:href="opi-20251231.xsd#opi_A450SeniorUnsecuredNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A450SeniorUnsecuredNotesMember" xlink:to="lab_opi_A450SeniorUnsecuredNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_MajorCustomersAxis_019dbc7a-b286-71b8-8e14-4f50665552c3_terseLabel_en-US" xlink:label="lab_srt_MajorCustomersAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Customer [Axis]</link:label>
    <link:label id="lab_srt_MajorCustomersAxis_label_en-US" xlink:label="lab_srt_MajorCustomersAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Customer [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MajorCustomersAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_MajorCustomersAxis" xlink:to="lab_srt_MajorCustomersAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LiabilitiesSubjectToCompromise_019dbc7a-b286-76bb-a1df-e3eadd8b7436_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesSubjectToCompromise" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Liabilities subject to compromise</link:label>
    <link:label id="lab_us-gaap_LiabilitiesSubjectToCompromise_019dd0bb-2f5b-71ff-81fa-a6bd7fba2b8b_totalLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesSubjectToCompromise" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total liabilities subject to compromise</link:label>
    <link:label id="lab_us-gaap_LiabilitiesSubjectToCompromise_label_en-US" xlink:label="lab_us-gaap_LiabilitiesSubjectToCompromise" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities Subject to Compromise</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesSubjectToCompromise" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesSubjectToCompromise"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesSubjectToCompromise" xlink:to="lab_us-gaap_LiabilitiesSubjectToCompromise" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LineOfCreditMember_019dbc7a-b286-7457-a04c-d8fd974ff999_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Line of Credit</link:label>
    <link:label id="lab_us-gaap_LineOfCreditMember_019dbc7a-b286-7a25-bce9-50551e7a0194_verboseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Line of Credit</link:label>
    <link:label id="lab_us-gaap_LineOfCreditMember_label_en-US" xlink:label="lab_us-gaap_LineOfCreditMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Line of Credit [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditMember" xlink:to="lab_us-gaap_LineOfCreditMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RetainedEarningsAccumulatedDeficit_019dbc7a-b286-734a-884f-71e10cc99778_terseLabel_en-US" xlink:label="lab_us-gaap_RetainedEarningsAccumulatedDeficit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cumulative net loss</link:label>
    <link:label id="lab_us-gaap_RetainedEarningsAccumulatedDeficit_label_en-US" xlink:label="lab_us-gaap_RetainedEarningsAccumulatedDeficit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retained Earnings (Accumulated Deficit)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetainedEarningsAccumulatedDeficit" xlink:to="lab_us-gaap_RetainedEarningsAccumulatedDeficit" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019dbc7a-b1cb-7f48-8adb-d41aa8109ba5_terseLabel_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Name of Property [Axis]</link:label>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_label_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Name of Property [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis" xlink:to="lab_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_YrEndFrValOfEqtyAwrdsGrntdInCvrdYrOutsdngAndUnvstdMember_terseLabel_en-US" xlink:label="lab_ecd_YrEndFrValOfEqtyAwrdsGrntdInCvrdYrOutsdngAndUnvstdMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested</link:label>
    <link:label id="lab_ecd_YrEndFrValOfEqtyAwrdsGrntdInCvrdYrOutsdngAndUnvstdMember_label_en-US" xlink:label="lab_ecd_YrEndFrValOfEqtyAwrdsGrntdInCvrdYrOutsdngAndUnvstdMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_YrEndFrValOfEqtyAwrdsGrntdInCvrdYrOutsdngAndUnvstdMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_YrEndFrValOfEqtyAwrdsGrntdInCvrdYrOutsdngAndUnvstdMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_YrEndFrValOfEqtyAwrdsGrntdInCvrdYrOutsdngAndUnvstdMember" xlink:to="lab_ecd_YrEndFrValOfEqtyAwrdsGrntdInCvrdYrOutsdngAndUnvstdMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_WorkingCapitalMember_019dd0c6-b5cb-7f87-8632-15a824f166bf_terseLabel_en-US" xlink:label="lab_opi_WorkingCapitalMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Working Capital</link:label>
    <link:label id="lab_opi_WorkingCapitalMember_label_en-US" xlink:label="lab_opi_WorkingCapitalMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Working Capital [Member]</link:label>
    <link:label id="lab_opi_WorkingCapitalMember_documentation_en-US" xlink:label="lab_opi_WorkingCapitalMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Working Capital</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_WorkingCapitalMember" xlink:href="opi-20251231.xsd#opi_WorkingCapitalMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_WorkingCapitalMember" xlink:to="lab_opi_WorkingCapitalMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SubsequentEventTypeDomain_019dbc7a-b1cb-750c-8f44-f928c8ff46a5_terseLabel_en-US" xlink:label="lab_us-gaap_SubsequentEventTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Subsequent Event Type [Domain]</link:label>
    <link:label id="lab_us-gaap_SubsequentEventTypeDomain_label_en-US" xlink:label="lab_us-gaap_SubsequentEventTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Subsequent Event Type [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsequentEventTypeDomain" xlink:to="lab_us-gaap_SubsequentEventTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInDueToRelatedParties_019dbc87-e198-7126-a112-fd09add9526a_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInDueToRelatedParties" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Due to related persons</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInDueToRelatedParties_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInDueToRelatedParties" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Due to Related Parties</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInDueToRelatedParties" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInDueToRelatedParties"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInDueToRelatedParties" xlink:to="lab_us-gaap_IncreaseDecreaseInDueToRelatedParties" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtorReorganizationItemsRevaluationOfAssetsAndLiabilities_019dd0c0-3451-70f9-82e5-e7a1626e6e67_terseLabel_en-US" xlink:label="lab_us-gaap_DebtorReorganizationItemsRevaluationOfAssetsAndLiabilities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt valuation adjustments</link:label>
    <link:label id="lab_us-gaap_DebtorReorganizationItemsRevaluationOfAssetsAndLiabilities_label_en-US" xlink:label="lab_us-gaap_DebtorReorganizationItemsRevaluationOfAssetsAndLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debtor Reorganization Items, Revaluation of Assets and Liabilities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtorReorganizationItemsRevaluationOfAssetsAndLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtorReorganizationItemsRevaluationOfAssetsAndLiabilities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtorReorganizationItemsRevaluationOfAssetsAndLiabilities" xlink:to="lab_us-gaap_DebtorReorganizationItemsRevaluationOfAssetsAndLiabilities" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_EqtyAwrdsInSummryCompstnTblForAplblYrMember_terseLabel_en-US" xlink:label="lab_ecd_EqtyAwrdsInSummryCompstnTblForAplblYrMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table</link:label>
    <link:label id="lab_ecd_EqtyAwrdsInSummryCompstnTblForAplblYrMember_label_en-US" xlink:label="lab_ecd_EqtyAwrdsInSummryCompstnTblForAplblYrMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_EqtyAwrdsInSummryCompstnTblForAplblYrMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_EqtyAwrdsInSummryCompstnTblForAplblYrMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_EqtyAwrdsInSummryCompstnTblForAplblYrMember" xlink:to="lab_ecd_EqtyAwrdsInSummryCompstnTblForAplblYrMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A4560ViewridgeRoadSanDiegoCAMember_019dbc7a-b287-7824-838e-2765000c1873_terseLabel_en-US" xlink:label="lab_opi_A4560ViewridgeRoadSanDiegoCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">4560 Viewridge Road, San Diego, CA</link:label>
    <link:label id="lab_opi_A4560ViewridgeRoadSanDiegoCAMember_label_en-US" xlink:label="lab_opi_A4560ViewridgeRoadSanDiegoCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">4560 Viewridge Road, San Diego, CA [Member]</link:label>
    <link:label id="lab_opi_A4560ViewridgeRoadSanDiegoCAMember_documentation_en-US" xlink:label="lab_opi_A4560ViewridgeRoadSanDiegoCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">4560 Viewridge Road, San Diego, CA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A4560ViewridgeRoadSanDiegoCAMember" xlink:href="opi-20251231.xsd#opi_A4560ViewridgeRoadSanDiegoCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A4560ViewridgeRoadSanDiegoCAMember" xlink:to="lab_opi_A4560ViewridgeRoadSanDiegoCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LongTermDebtTermsDomain_019dd60f-acbc-7bce-a3d6-b92bcf860606_terseLabel_en-US" xlink:label="lab_opi_LongTermDebtTermsDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Terms [Domain]</link:label>
    <link:label id="lab_opi_LongTermDebtTermsDomain_label_en-US" xlink:label="lab_opi_LongTermDebtTermsDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Terms [Domain]</link:label>
    <link:label id="lab_opi_LongTermDebtTermsDomain_documentation_en-US" xlink:label="lab_opi_LongTermDebtTermsDomain" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Terms [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LongTermDebtTermsDomain" xlink:href="opi-20251231.xsd#opi_LongTermDebtTermsDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LongTermDebtTermsDomain" xlink:to="lab_opi_LongTermDebtTermsDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A3450SeniorUnsecuredNotesMember_019dbcab-d6b2-7414-9173-0979c545296f_terseLabel_en-US" xlink:label="lab_opi_A3450SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior unsecured notes, 3.450% interest rate, due in 2031</link:label>
    <link:label id="lab_opi_A3450SeniorUnsecuredNotesMember_label_en-US" xlink:label="lab_opi_A3450SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">3.450% Senior Unsecured Notes [Member]</link:label>
    <link:label id="lab_opi_A3450SeniorUnsecuredNotesMember_documentation_en-US" xlink:label="lab_opi_A3450SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">3.450% Senior Unsecured Notes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A3450SeniorUnsecuredNotesMember" xlink:href="opi-20251231.xsd#opi_A3450SeniorUnsecuredNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A3450SeniorUnsecuredNotesMember" xlink:to="lab_opi_A3450SeniorUnsecuredNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_AdditionalAreaOfRealEstateProperty_019dbc7a-b286-7cfb-9799-e638981a7964_terseLabel_en-US" xlink:label="lab_opi_AdditionalAreaOfRealEstateProperty" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Additional area of real estate property (in square feet)</link:label>
    <link:label id="lab_opi_AdditionalAreaOfRealEstateProperty_label_en-US" xlink:label="lab_opi_AdditionalAreaOfRealEstateProperty" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Additional Area Of Real Estate Property</link:label>
    <link:label id="lab_opi_AdditionalAreaOfRealEstateProperty_documentation_en-US" xlink:label="lab_opi_AdditionalAreaOfRealEstateProperty" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Additional Area Of Real Estate Property</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_AdditionalAreaOfRealEstateProperty" xlink:href="opi-20251231.xsd#opi_AdditionalAreaOfRealEstateProperty"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_AdditionalAreaOfRealEstateProperty" xlink:to="lab_opi_AdditionalAreaOfRealEstateProperty" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementTable_019dbc7a-b287-7f93-87aa-fe35d929ecbc_terseLabel_en-US" xlink:label="lab_us-gaap_StatementTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statement [Table]</link:label>
    <link:label id="lab_us-gaap_StatementTable_label_en-US" xlink:label="lab_us-gaap_StatementTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementTable" xlink:to="lab_us-gaap_StatementTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_019dbc84-e5c5-79d9-91d8-09a68dd5b98f_terseLabel_en-US" xlink:label="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Adjustments to reconcile net loss to net cash (used in) provided by operating activities:</link:label>
    <link:label id="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_label_en-US" xlink:label="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_019dbc7a-b287-7151-b974-1b2a79ce44f3_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">CASH FLOWS FROM FINANCING ACTIVITIES:</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A1212PittsfordVictorRoadPittsfordNYMember_019dbc7a-b1cb-77d4-a961-eee8d5d839ff_terseLabel_en-US" xlink:label="lab_opi_A1212PittsfordVictorRoadPittsfordNYMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">1212 Pittsford - Victor Road, Pittsford, NY</link:label>
    <link:label id="lab_opi_A1212PittsfordVictorRoadPittsfordNYMember_label_en-US" xlink:label="lab_opi_A1212PittsfordVictorRoadPittsfordNYMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">1212 Pittsford - Victor Road, Pittsford, NY [Member]</link:label>
    <link:label id="lab_opi_A1212PittsfordVictorRoadPittsfordNYMember_documentation_en-US" xlink:label="lab_opi_A1212PittsfordVictorRoadPittsfordNYMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">1212 Pittsford - Victor Road, Pittsford, NY [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A1212PittsfordVictorRoadPittsfordNYMember" xlink:href="opi-20251231.xsd#opi_A1212PittsfordVictorRoadPittsfordNYMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A1212PittsfordVictorRoadPittsfordNYMember" xlink:to="lab_opi_A1212PittsfordVictorRoadPittsfordNYMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_VariableRateDomain_019dd62b-3268-78a9-9a31-e4d496070041_terseLabel_en-US" xlink:label="lab_us-gaap_VariableRateDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Variable Rate [Domain]</link:label>
    <link:label id="lab_us-gaap_VariableRateDomain_label_en-US" xlink:label="lab_us-gaap_VariableRateDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Variable Rate [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_VariableRateDomain" xlink:to="lab_us-gaap_VariableRateDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageClosingStockPriceOnStockExchange_019dbc7a-b30c-7db9-aaa3-5415c946a0a2_terseLabel_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageClosingStockPriceOnStockExchange" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage of average closing stock price on stock exchange</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageClosingStockPriceOnStockExchange_label_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageClosingStockPriceOnStockExchange" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction Base Management Fee Payable As Percentage of Average Closing Stock Price on Stock Exchange</link:label>
    <link:label id="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageClosingStockPriceOnStockExchange_documentation_en-US" xlink:label="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageClosingStockPriceOnStockExchange" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the base management fee payable as a percentage of average closing price per share of common shares on NYSE.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageClosingStockPriceOnStockExchange" xlink:href="opi-20251231.xsd#opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageClosingStockPriceOnStockExchange"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageClosingStockPriceOnStockExchange" xlink:to="lab_opi_RelatedPartyTransactionBaseManagementFeePayableAsPercentageOfAverageClosingStockPriceOnStockExchange" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock_019dbc7a-b287-7a7b-b4a2-af7998ec1fa3_terseLabel_en-US" xlink:label="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Business</link:label>
    <link:label id="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:to="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RepaymentsOfUnsecuredDebt_019dbc8a-1c1f-749f-8316-d48e2622bea5_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_RepaymentsOfUnsecuredDebt" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Repayment of senior unsecured notes</link:label>
    <link:label id="lab_us-gaap_RepaymentsOfUnsecuredDebt_label_en-US" xlink:label="lab_us-gaap_RepaymentsOfUnsecuredDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Repayments of Unsecured Debt</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfUnsecuredDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RepaymentsOfUnsecuredDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RepaymentsOfUnsecuredDebt" xlink:to="lab_us-gaap_RepaymentsOfUnsecuredDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A18010BurtStreetOmahaNEMember_019dbc7a-b1cb-77be-a5d1-309fc4d5c5af_terseLabel_en-US" xlink:label="lab_opi_A18010BurtStreetOmahaNEMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">18010 Burt Street, Omaha, NE</link:label>
    <link:label id="lab_opi_A18010BurtStreetOmahaNEMember_label_en-US" xlink:label="lab_opi_A18010BurtStreetOmahaNEMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">18010 Burt Street, Omaha, NE [Member]</link:label>
    <link:label id="lab_opi_A18010BurtStreetOmahaNEMember_documentation_en-US" xlink:label="lab_opi_A18010BurtStreetOmahaNEMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">18010 Burt Street, Omaha, NE</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A18010BurtStreetOmahaNEMember" xlink:href="opi-20251231.xsd#opi_A18010BurtStreetOmahaNEMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A18010BurtStreetOmahaNEMember" xlink:to="lab_opi_A18010BurtStreetOmahaNEMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_AllAdjToCompMember_terseLabel_en-US" xlink:label="lab_ecd_AllAdjToCompMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">All Adjustments to Compensation</link:label>
    <link:label id="lab_ecd_AllAdjToCompMember_label_en-US" xlink:label="lab_ecd_AllAdjToCompMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">All Adjustments to Compensation [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AllAdjToCompMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AllAdjToCompMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_AllAdjToCompMember" xlink:to="lab_ecd_AllAdjToCompMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A3550GreenCourtAnnArborMIMember_019dbc7a-b287-7b61-8c1a-110d0ba8613d_terseLabel_en-US" xlink:label="lab_opi_A3550GreenCourtAnnArborMIMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">3550 Green Court, Ann Arbor, MI</link:label>
    <link:label id="lab_opi_A3550GreenCourtAnnArborMIMember_label_en-US" xlink:label="lab_opi_A3550GreenCourtAnnArborMIMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">3550 Green Court, Ann Arbor, MI [Member]</link:label>
    <link:label id="lab_opi_A3550GreenCourtAnnArborMIMember_documentation_en-US" xlink:label="lab_opi_A3550GreenCourtAnnArborMIMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">3550 Green Court, Ann Arbor, MI [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A3550GreenCourtAnnArborMIMember" xlink:href="opi-20251231.xsd#opi_A3550GreenCourtAnnArborMIMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A3550GreenCourtAnnArborMIMember" xlink:to="lab_opi_A3550GreenCourtAnnArborMIMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ShareBasedCompensationAwardsNumberOfInstallments_019dbc7a-b1cb-7a70-8aef-591271c64c44_terseLabel_en-US" xlink:label="lab_opi_ShareBasedCompensationAwardsNumberOfInstallments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of installments</link:label>
    <link:label id="lab_opi_ShareBasedCompensationAwardsNumberOfInstallments_label_en-US" xlink:label="lab_opi_ShareBasedCompensationAwardsNumberOfInstallments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Awards, Number Of Installments</link:label>
    <link:label id="lab_opi_ShareBasedCompensationAwardsNumberOfInstallments_documentation_en-US" xlink:label="lab_opi_ShareBasedCompensationAwardsNumberOfInstallments" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Awards, Number Of Installments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ShareBasedCompensationAwardsNumberOfInstallments" xlink:href="opi-20251231.xsd#opi_ShareBasedCompensationAwardsNumberOfInstallments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ShareBasedCompensationAwardsNumberOfInstallments" xlink:to="lab_opi_ShareBasedCompensationAwardsNumberOfInstallments" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_AmendmentFlag_019dbc7a-b287-7360-aeee-3e44af032d8e_terseLabel_en-US" xlink:label="lab_dei_AmendmentFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amendment Flag</link:label>
    <link:label id="lab_dei_AmendmentFlag_label_en-US" xlink:label="lab_dei_AmendmentFlag" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amendment Flag</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_AmendmentFlag"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_AmendmentFlag" xlink:to="lab_dei_AmendmentFlag" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment_019dbc89-4a7d-7e24-ab11-f02bde2b0124_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from sale of property, net</link:label>
    <link:label id="lab_us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment_label_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Sale, Real Estate, Held-for-Investment</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment" xlink:to="lab_us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_TrdArrTerminationDate_terseLabel_en-US" xlink:label="lab_ecd_TrdArrTerminationDate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Termination Date</link:label>
    <link:label id="lab_ecd_TrdArrTerminationDate_label_en-US" xlink:label="lab_ecd_TrdArrTerminationDate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Trading Arrangement Termination Date</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_TrdArrTerminationDate" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_TrdArrTerminationDate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_TrdArrTerminationDate" xlink:to="lab_ecd_TrdArrTerminationDate" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SaleOfStockWeightedAveragePricePerShare_019dd0dc-686b-74c0-98f1-a77f28fa105a_terseLabel_en-US" xlink:label="lab_opi_SaleOfStockWeightedAveragePricePerShare" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted average share price of common shares sold (in dollars per share)</link:label>
    <link:label id="lab_opi_SaleOfStockWeightedAveragePricePerShare_label_en-US" xlink:label="lab_opi_SaleOfStockWeightedAveragePricePerShare" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Of Stock, Weighted Average Price Per Share</link:label>
    <link:label id="lab_opi_SaleOfStockWeightedAveragePricePerShare_documentation_en-US" xlink:label="lab_opi_SaleOfStockWeightedAveragePricePerShare" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Of Stock, Weighted Average Price Per Share</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SaleOfStockWeightedAveragePricePerShare" xlink:href="opi-20251231.xsd#opi_SaleOfStockWeightedAveragePricePerShare"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SaleOfStockWeightedAveragePricePerShare" xlink:to="lab_opi_SaleOfStockWeightedAveragePricePerShare" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_InsiderTrdPoliciesProcAdoptedFlag_terseLabel_en-US" xlink:label="lab_ecd_InsiderTrdPoliciesProcAdoptedFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Insider Trading Policies and Procedures Adopted</link:label>
    <link:label id="lab_ecd_InsiderTrdPoliciesProcAdoptedFlag_label_en-US" xlink:label="lab_ecd_InsiderTrdPoliciesProcAdoptedFlag" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Insider Trading Policies and Procedures Adopted [Flag]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_InsiderTrdPoliciesProcAdoptedFlag" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_InsiderTrdPoliciesProcAdoptedFlag"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_InsiderTrdPoliciesProcAdoptedFlag" xlink:to="lab_ecd_InsiderTrdPoliciesProcAdoptedFlag" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFour_019dbc7a-b1cb-74e4-95cc-71fe38dc7061_terseLabel_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2028</link:label>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFour_label_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Finance Costs, Future Amortization Expense Year Four</link:label>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFour_documentation_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFour" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of amortization of deferred financing fees expected to be recognized during year four of the five succeeding fiscal years.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFour" xlink:href="opi-20251231.xsd#opi_DeferredFinanceCostsFutureAmortizationExpenseYearFour"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFour" xlink:to="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseYearFour" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseAbstract_019dbc7a-b286-769c-af2d-d8227aad6c90_terseLabel_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Future amortization of deferred financing fees</link:label>
    <link:label id="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseAbstract_label_en-US" xlink:label="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Finance Costs, Future Amortization Expense [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_DeferredFinanceCostsFutureAmortizationExpenseAbstract" xlink:href="opi-20251231.xsd#opi_DeferredFinanceCostsFutureAmortizationExpenseAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_DeferredFinanceCostsFutureAmortizationExpenseAbstract" xlink:to="lab_opi_DeferredFinanceCostsFutureAmortizationExpenseAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationAwardTrancheThreeMember_019dbc7a-b30c-71ba-a938-940e034686ce_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationAwardTrancheThreeMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement, Tranche 3</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationAwardTrancheThreeMember_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationAwardTrancheThreeMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement, Tranche Three [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationAwardTrancheThreeMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationAwardTrancheThreeMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationAwardTrancheThreeMember" xlink:to="lab_us-gaap_ShareBasedCompensationAwardTrancheThreeMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_ChicagoILMember_019dbc7a-b1cb-706c-bc9f-238389cd66e9_terseLabel_en-US" xlink:label="lab_opi_ChicagoILMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Chicago, IL</link:label>
    <link:label id="lab_opi_ChicagoILMember_label_en-US" xlink:label="lab_opi_ChicagoILMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Chicago, IL [Member]</link:label>
    <link:label id="lab_opi_ChicagoILMember_documentation_en-US" xlink:label="lab_opi_ChicagoILMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Chicago, IL</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_ChicagoILMember" xlink:href="opi-20251231.xsd#opi_ChicagoILMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_ChicagoILMember" xlink:to="lab_opi_ChicagoILMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInDueFromRelatedParties_019dbc84-9551-7812-b653-e918b5014007_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInDueFromRelatedParties" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Due from related persons</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInDueFromRelatedParties_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInDueFromRelatedParties" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Due from Related Parties</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInDueFromRelatedParties" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInDueFromRelatedParties"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInDueFromRelatedParties" xlink:to="lab_us-gaap_IncreaseDecreaseInDueFromRelatedParties" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019dbc7a-b1cb-7906-892f-8814dcb27969_terseLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted average common shares outstanding (basic) (in shares)</link:label>
    <link:label id="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019dbc7a-b1cb-7b23-bc0e-3a87db317691_verboseLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Weighted average common shares outstanding - basic (in shares)</link:label>
    <link:label id="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_label_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Weighted Average Number of Shares Outstanding, Basic</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:to="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_NumberOfOperatingLeaseExecuted_019dbc7a-b287-7332-9692-59b7f6a1cabe_terseLabel_en-US" xlink:label="lab_opi_NumberOfOperatingLeaseExecuted" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of leases entered</link:label>
    <link:label id="lab_opi_NumberOfOperatingLeaseExecuted_label_en-US" xlink:label="lab_opi_NumberOfOperatingLeaseExecuted" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number Of Operating Lease Executed</link:label>
    <link:label id="lab_opi_NumberOfOperatingLeaseExecuted_documentation_en-US" xlink:label="lab_opi_NumberOfOperatingLeaseExecuted" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents number of leases executed during the reporting period.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_NumberOfOperatingLeaseExecuted" xlink:href="opi-20251231.xsd#opi_NumberOfOperatingLeaseExecuted"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_NumberOfOperatingLeaseExecuted" xlink:to="lab_opi_NumberOfOperatingLeaseExecuted" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_019dbc7a-b30c-7063-b702-7cf926d3a79d_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Earnings Per Share, Basic and Diluted</link:label>
    <link:label id="lab_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RelatedPartyTransactionDomain_019dbc7a-b287-778a-861a-05ab6d2ab372_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Related Party Transaction [Domain]</link:label>
    <link:label id="lab_us-gaap_RelatedPartyTransactionDomain_label_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transaction [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain" xlink:to="lab_us-gaap_RelatedPartyTransactionDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SegmentReportingAbstract_019dbc7a-b1cb-7855-be57-8c16e6a6ed18_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentReportingAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Segment Reporting [Abstract]</link:label>
    <link:label id="lab_us-gaap_SegmentReportingAbstract_label_en-US" xlink:label="lab_us-gaap_SegmentReportingAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentReportingAbstract" xlink:to="lab_us-gaap_SegmentReportingAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_019dbc7a-b286-7502-baf5-8d17ef0da027_verboseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Projected future amortization of net intangible lease assets and liabilities, excluding those classified as discontinued operations</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A7958SouthChesterStreetCentennialCOMember_019dbc7a-b286-728e-9db4-cf594c4deb28_terseLabel_en-US" xlink:label="lab_opi_A7958SouthChesterStreetCentennialCOMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">7958 South Chester Street, Centennial, CO</link:label>
    <link:label id="lab_opi_A7958SouthChesterStreetCentennialCOMember_label_en-US" xlink:label="lab_opi_A7958SouthChesterStreetCentennialCOMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">7958 South Chester Street, Centennial, CO [Member]</link:label>
    <link:label id="lab_opi_A7958SouthChesterStreetCentennialCOMember_documentation_en-US" xlink:label="lab_opi_A7958SouthChesterStreetCentennialCOMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">7958 South Chester Street, Centennial, CO [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A7958SouthChesterStreetCentennialCOMember" xlink:href="opi-20251231.xsd#opi_A7958SouthChesterStreetCentennialCOMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A7958SouthChesterStreetCentennialCOMember" xlink:to="lab_opi_A7958SouthChesterStreetCentennialCOMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_RestonVAMember_019dbc7a-b1cb-71f1-b21a-4d73612b723f_terseLabel_en-US" xlink:label="lab_opi_RestonVAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reston, VA</link:label>
    <link:label id="lab_opi_RestonVAMember_label_en-US" xlink:label="lab_opi_RestonVAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reston, VA [Member]</link:label>
    <link:label id="lab_opi_RestonVAMember_documentation_en-US" xlink:label="lab_opi_RestonVAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Reston, VA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_RestonVAMember" xlink:href="opi-20251231.xsd#opi_RestonVAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_RestonVAMember" xlink:to="lab_opi_RestonVAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtDisclosureAbstract_019dbc7a-b30c-7eba-afc9-53bfa4d93df9_terseLabel_en-US" xlink:label="lab_us-gaap_DebtDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Disclosure [Abstract]</link:label>
    <link:label id="lab_us-gaap_DebtDisclosureAbstract_label_en-US" xlink:label="lab_us-gaap_DebtDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Disclosure [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtDisclosureAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtDisclosureAbstract" xlink:to="lab_us-gaap_DebtDisclosureAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CostsAndExpensesAbstract_019dbc7a-b1cb-73e6-bab6-a83e377867d4_terseLabel_en-US" xlink:label="lab_us-gaap_CostsAndExpensesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Expenses:</link:label>
    <link:label id="lab_us-gaap_CostsAndExpensesAbstract_label_en-US" xlink:label="lab_us-gaap_CostsAndExpensesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Costs and Expenses [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpensesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostsAndExpensesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CostsAndExpensesAbstract" xlink:to="lab_us-gaap_CostsAndExpensesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A2548CampbellPlaceCarlsbadCAMember_019dbc7a-b287-7732-a82f-e218a464df83_terseLabel_en-US" xlink:label="lab_opi_A2548CampbellPlaceCarlsbadCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2548 Campbell Place, Carlsbad, CA</link:label>
    <link:label id="lab_opi_A2548CampbellPlaceCarlsbadCAMember_label_en-US" xlink:label="lab_opi_A2548CampbellPlaceCarlsbadCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2548 Campbell Place, Carlsbad, CA [Member]</link:label>
    <link:label id="lab_opi_A2548CampbellPlaceCarlsbadCAMember_documentation_en-US" xlink:label="lab_opi_A2548CampbellPlaceCarlsbadCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2548 Campbell Place, Carlsbad, CA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A2548CampbellPlaceCarlsbadCAMember" xlink:href="opi-20251231.xsd#opi_A2548CampbellPlaceCarlsbadCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A2548CampbellPlaceCarlsbadCAMember" xlink:to="lab_opi_A2548CampbellPlaceCarlsbadCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_HUB1415NapervilleILMember_019dbc7a-b286-78bd-8a82-481b4c02878b_terseLabel_en-US" xlink:label="lab_opi_HUB1415NapervilleILMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">HUB 1415, Naperville IL</link:label>
    <link:label id="lab_opi_HUB1415NapervilleILMember_label_en-US" xlink:label="lab_opi_HUB1415NapervilleILMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">HUB 1415, Naperville IL [Member]</link:label>
    <link:label id="lab_opi_HUB1415NapervilleILMember_documentation_en-US" xlink:label="lab_opi_HUB1415NapervilleILMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">HUB 1415, Naperville IL</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_HUB1415NapervilleILMember" xlink:href="opi-20251231.xsd#opi_HUB1415NapervilleILMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_HUB1415NapervilleILMember" xlink:to="lab_opi_HUB1415NapervilleILMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A330075thAvenueLandoverMDMember_019dbc7a-b286-748a-8e0a-6d7be0c2bbf5_terseLabel_en-US" xlink:label="lab_opi_A330075thAvenueLandoverMDMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">3300 75th Avenue, Landover, MD</link:label>
    <link:label id="lab_opi_A330075thAvenueLandoverMDMember_label_en-US" xlink:label="lab_opi_A330075thAvenueLandoverMDMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">3300 75th Avenue, Landover, MD [Member]</link:label>
    <link:label id="lab_opi_A330075thAvenueLandoverMDMember_documentation_en-US" xlink:label="lab_opi_A330075thAvenueLandoverMDMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">3300 75th Avenue, Landover, MD</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A330075thAvenueLandoverMDMember" xlink:href="opi-20251231.xsd#opi_A330075thAvenueLandoverMDMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A330075thAvenueLandoverMDMember" xlink:to="lab_opi_A330075thAvenueLandoverMDMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RestructuringAndRelatedActivitiesAbstract_label_en-US" xlink:label="lab_us-gaap_RestructuringAndRelatedActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Restructuring and Related Activities [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringAndRelatedActivitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringAndRelatedActivitiesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RestructuringAndRelatedActivitiesAbstract" xlink:to="lab_us-gaap_RestructuringAndRelatedActivitiesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_ForgoneRecoveryDueToExpenseOfEnforcementAmt_terseLabel_en-US" xlink:label="lab_ecd_ForgoneRecoveryDueToExpenseOfEnforcementAmt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Forgone Recovery due to Expense of Enforcement, Amount</link:label>
    <link:label id="lab_ecd_ForgoneRecoveryDueToExpenseOfEnforcementAmt_label_en-US" xlink:label="lab_ecd_ForgoneRecoveryDueToExpenseOfEnforcementAmt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Forgone Recovery due to Expense of Enforcement, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_ForgoneRecoveryDueToExpenseOfEnforcementAmt" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_ForgoneRecoveryDueToExpenseOfEnforcementAmt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_ForgoneRecoveryDueToExpenseOfEnforcementAmt" xlink:to="lab_ecd_ForgoneRecoveryDueToExpenseOfEnforcementAmt" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_CommonStockDividendsQualifiedDividendDistributionPercentage_019dbc7a-b1cb-7b16-befb-e4b6c3e4ede0_verboseLabel_en-US" xlink:label="lab_opi_CommonStockDividendsQualifiedDividendDistributionPercentage" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Characterization of Distribution, Quality Dividend</link:label>
    <link:label id="lab_opi_CommonStockDividendsQualifiedDividendDistributionPercentage_label_en-US" xlink:label="lab_opi_CommonStockDividendsQualifiedDividendDistributionPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock Dividends Qualified Dividend Distribution Percentage</link:label>
    <link:label id="lab_opi_CommonStockDividendsQualifiedDividendDistributionPercentage_documentation_en-US" xlink:label="lab_opi_CommonStockDividendsQualifiedDividendDistributionPercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the percentage of qualified dividend distributed on common stock.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_CommonStockDividendsQualifiedDividendDistributionPercentage" xlink:href="opi-20251231.xsd#opi_CommonStockDividendsQualifiedDividendDistributionPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_CommonStockDividendsQualifiedDividendDistributionPercentage" xlink:to="lab_opi_CommonStockDividendsQualifiedDividendDistributionPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ConsolidatedEntitiesAxis_019dd081-dfd7-7f8d-b0b5-6e50d97f0165_terseLabel_en-US" xlink:label="lab_srt_ConsolidatedEntitiesAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Consolidated Entities [Axis]</link:label>
    <link:label id="lab_srt_ConsolidatedEntitiesAxis_label_en-US" xlink:label="lab_srt_ConsolidatedEntitiesAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Consolidated Entities [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ConsolidatedEntitiesAxis" xlink:to="lab_srt_ConsolidatedEntitiesAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019dbc7a-b287-7dc0-acc5-6a9d81fa4983_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award [Line Items]</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockParOrStatedValuePerShare_019dbc7a-b286-7ecc-bf27-9727282cd548_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockParOrStatedValuePerShare" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common shares of beneficial interest, par value (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_CommonStockParOrStatedValuePerShare_label_en-US" xlink:label="lab_us-gaap_CommonStockParOrStatedValuePerShare" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock, Par or Stated Value Per Share</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockParOrStatedValuePerShare" xlink:to="lab_us-gaap_CommonStockParOrStatedValuePerShare" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ImpairmentOfRealEstate_019dbc7a-b1cb-7c78-82c9-28dda5f9e3fa_terseLabel_en-US" xlink:label="lab_us-gaap_ImpairmentOfRealEstate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss on impairment of real estate</link:label>
    <link:label id="lab_us-gaap_ImpairmentOfRealEstate_019dbc7a-b1cb-78dd-8a87-62321b6ddd74_negatedLabel_en-US" xlink:label="lab_us-gaap_ImpairmentOfRealEstate" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Loss on Impairment of Real Estate</link:label>
    <link:label id="lab_us-gaap_ImpairmentOfRealEstate_label_en-US" xlink:label="lab_us-gaap_ImpairmentOfRealEstate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Impairment of Real Estate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfRealEstate" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ImpairmentOfRealEstate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ImpairmentOfRealEstate" xlink:to="lab_us-gaap_ImpairmentOfRealEstate" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_SaleOfStockAuthorizedAmount_019dd0dc-686b-7b9f-a02c-86b6e6091507_terseLabel_en-US" xlink:label="lab_opi_SaleOfStockAuthorizedAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Authorized sale price of common stock</link:label>
    <link:label id="lab_opi_SaleOfStockAuthorizedAmount_label_en-US" xlink:label="lab_opi_SaleOfStockAuthorizedAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Of Stock, Authorized Amount</link:label>
    <link:label id="lab_opi_SaleOfStockAuthorizedAmount_documentation_en-US" xlink:label="lab_opi_SaleOfStockAuthorizedAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Of Stock, Authorized Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_SaleOfStockAuthorizedAmount" xlink:href="opi-20251231.xsd#opi_SaleOfStockAuthorizedAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_SaleOfStockAuthorizedAmount" xlink:to="lab_opi_SaleOfStockAuthorizedAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_UseOfEstimates_019dbc7a-b30c-77b3-991a-a90b6a565718_terseLabel_en-US" xlink:label="lab_us-gaap_UseOfEstimates" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Use of Estimates</link:label>
    <link:label id="lab_us-gaap_UseOfEstimates_label_en-US" xlink:label="lab_us-gaap_UseOfEstimates" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Use of Estimates, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UseOfEstimates" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_UseOfEstimates"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UseOfEstimates" xlink:to="lab_us-gaap_UseOfEstimates" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_TerminationFeeRemainingTermAssumption_019dbc7a-b286-7635-a47d-5cefaa182aac_terseLabel_en-US" xlink:label="lab_opi_TerminationFeeRemainingTermAssumption" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Remaining termination fee term</link:label>
    <link:label id="lab_opi_TerminationFeeRemainingTermAssumption_label_en-US" xlink:label="lab_opi_TerminationFeeRemainingTermAssumption" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Termination Fee Remaining Term Assumption</link:label>
    <link:label id="lab_opi_TerminationFeeRemainingTermAssumption_documentation_en-US" xlink:label="lab_opi_TerminationFeeRemainingTermAssumption" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the remaining term assumption in years used to calculate the fee for termination of one or both of the company's amended management agreements for a performance reason.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_TerminationFeeRemainingTermAssumption" xlink:href="opi-20251231.xsd#opi_TerminationFeeRemainingTermAssumption"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_TerminationFeeRemainingTermAssumption" xlink:to="lab_opi_TerminationFeeRemainingTermAssumption" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_InsiderTradingArrLineItems_label_en-US" xlink:label="lab_ecd_InsiderTradingArrLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Insider Trading Arrangements [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_InsiderTradingArrLineItems" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_InsiderTradingArrLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_InsiderTradingArrLineItems" xlink:to="lab_ecd_InsiderTradingArrLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_Liabilities_019dbc7a-b287-78a9-8eb3-7c847d744872_totalLabel_en-US" xlink:label="lab_us-gaap_Liabilities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total liabilities</link:label>
    <link:label id="lab_us-gaap_Liabilities_label_en-US" xlink:label="lab_us-gaap_Liabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Liabilities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Liabilities" xlink:to="lab_us-gaap_Liabilities" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_019dbc7a-b1cb-76cd-9d94-fcd2ecd62eea_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityCommitmentFeePercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Commitment fee percentage</link:label>
    <link:label id="lab_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_label_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityCommitmentFeePercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Line of Credit Facility, Commitment Fee Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage" xlink:to="lab_us-gaap_LineOfCreditFacilityCommitmentFeePercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_PnsnAdjsPrrSvcCstMember_terseLabel_en-US" xlink:label="lab_ecd_PnsnAdjsPrrSvcCstMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pension Adjustments Prior Service Cost</link:label>
    <link:label id="lab_ecd_PnsnAdjsPrrSvcCstMember_label_en-US" xlink:label="lab_ecd_PnsnAdjsPrrSvcCstMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pension Adjustments Prior Service Cost [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_PnsnAdjsPrrSvcCstMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_PnsnAdjsPrrSvcCstMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_PnsnAdjsPrrSvcCstMember" xlink:to="lab_ecd_PnsnAdjsPrrSvcCstMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_MtrlTermsOfTrdArrTextBlock_terseLabel_en-US" xlink:label="lab_ecd_MtrlTermsOfTrdArrTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Material Terms of Trading Arrangement</link:label>
    <link:label id="lab_ecd_MtrlTermsOfTrdArrTextBlock_label_en-US" xlink:label="lab_ecd_MtrlTermsOfTrdArrTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Material Terms of Trading Arrangement [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_MtrlTermsOfTrdArrTextBlock" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_MtrlTermsOfTrdArrTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_MtrlTermsOfTrdArrTextBlock" xlink:to="lab_ecd_MtrlTermsOfTrdArrTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_CapitolPlaceSacramentoCAMember_019dbc7a-b287-7e51-afcf-3d8081917c9b_terseLabel_en-US" xlink:label="lab_opi_CapitolPlaceSacramentoCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Capitol Place, Sacramento, CA</link:label>
    <link:label id="lab_opi_CapitolPlaceSacramentoCAMember_label_en-US" xlink:label="lab_opi_CapitolPlaceSacramentoCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capitol Place, Sacramento, CA [Member]</link:label>
    <link:label id="lab_opi_CapitolPlaceSacramentoCAMember_documentation_en-US" xlink:label="lab_opi_CapitolPlaceSacramentoCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Capitol Place, Sacramento, CA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_CapitolPlaceSacramentoCAMember" xlink:href="opi-20251231.xsd#opi_CapitolPlaceSacramentoCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_CapitolPlaceSacramentoCAMember" xlink:to="lab_opi_CapitolPlaceSacramentoCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_LongTermDebtTermsAxis_019dd60f-acbc-731e-8b2a-05bdd63fea12_terseLabel_en-US" xlink:label="lab_opi_LongTermDebtTermsAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Terms [Axis]</link:label>
    <link:label id="lab_opi_LongTermDebtTermsAxis_label_en-US" xlink:label="lab_opi_LongTermDebtTermsAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Terms [Axis]</link:label>
    <link:label id="lab_opi_LongTermDebtTermsAxis_documentation_en-US" xlink:label="lab_opi_LongTermDebtTermsAxis" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Terms</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_LongTermDebtTermsAxis" xlink:href="opi-20251231.xsd#opi_LongTermDebtTermsAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_LongTermDebtTermsAxis" xlink:to="lab_opi_LongTermDebtTermsAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues_019dbc7a-b1cb-7408-9df1-8150362bcc01_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Issuance of common shares</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Issued During Period, Value, New Issues</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:to="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_VariableRateAxis_019dd62b-3268-76d4-bee9-3f5dc6e32e7a_terseLabel_en-US" xlink:label="lab_us-gaap_VariableRateAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Variable Rate [Axis]</link:label>
    <link:label id="lab_us-gaap_VariableRateAxis_label_en-US" xlink:label="lab_us-gaap_VariableRateAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Variable Rate [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_VariableRateAxis" xlink:to="lab_us-gaap_VariableRateAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_OfficersandOtherEmployeesMember_019dbc7a-b1cb-7fd0-b77f-a2b951ca8b87_terseLabel_en-US" xlink:label="lab_opi_OfficersandOtherEmployeesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Officers and Other Employees</link:label>
    <link:label id="lab_opi_OfficersandOtherEmployeesMember_label_en-US" xlink:label="lab_opi_OfficersandOtherEmployeesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Officers and Other Employees [Member]</link:label>
    <link:label id="lab_opi_OfficersandOtherEmployeesMember_documentation_en-US" xlink:label="lab_opi_OfficersandOtherEmployeesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Officers and Other Employees [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_OfficersandOtherEmployeesMember" xlink:href="opi-20251231.xsd#opi_OfficersandOtherEmployeesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_OfficersandOtherEmployeesMember" xlink:to="lab_opi_OfficersandOtherEmployeesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_CounterpartyNameAxis_019dbc7a-b287-7983-aec7-f83a7a7694c7_terseLabel_en-US" xlink:label="lab_srt_CounterpartyNameAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Counterparty Name [Axis]</link:label>
    <link:label id="lab_srt_CounterpartyNameAxis_label_en-US" xlink:label="lab_srt_CounterpartyNameAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Counterparty Name [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_CounterpartyNameAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_CounterpartyNameAxis" xlink:to="lab_srt_CounterpartyNameAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityIncorporationStateCountryCode_019dbc7a-b286-750d-82ff-c0705681e9eb_terseLabel_en-US" xlink:label="lab_dei_EntityIncorporationStateCountryCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Incorporation, State or Country Code</link:label>
    <link:label id="lab_dei_EntityIncorporationStateCountryCode_label_en-US" xlink:label="lab_dei_EntityIncorporationStateCountryCode" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Incorporation, State or Country Code</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityIncorporationStateCountryCode" xlink:to="lab_dei_EntityIncorporationStateCountryCode" xlink:type="arc" order="1"/>
    <link:label id="lab_opi_A4344CarmichaelRoadMontgomeryALMember_019dbc7a-b287-7e1b-ab69-04747723bc12_terseLabel_en-US" xlink:label="lab_opi_A4344CarmichaelRoadMontgomeryALMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">4344 Carmichael Road, Montgomery, AL</link:label>
    <link:label id="lab_opi_A4344CarmichaelRoadMontgomeryALMember_label_en-US" xlink:label="lab_opi_A4344CarmichaelRoadMontgomeryALMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">4344 Carmichael Road, Montgomery, AL [Member]</link:label>
    <link:label id="lab_opi_A4344CarmichaelRoadMontgomeryALMember_documentation_en-US" xlink:label="lab_opi_A4344CarmichaelRoadMontgomeryALMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">4344 Carmichael Road, Montgomery, AL</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_opi_A4344CarmichaelRoadMontgomeryALMember" xlink:href="opi-20251231.xsd#opi_A4344CarmichaelRoadMontgomeryALMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_opi_A4344CarmichaelRoadMontgomeryALMember" xlink:to="lab_opi_A4344CarmichaelRoadMontgomeryALMember" xlink:type="arc" order="1"/>
    <link:label id="lab_ecd_NonNeosMember_terseLabel_en-US" xlink:label="lab_ecd_NonNeosMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Non-NEOs</link:label>
    <link:label id="lab_ecd_NonNeosMember_label_en-US" xlink:label="lab_ecd_NonNeosMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Non-NEOs [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_ecd_NonNeosMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_NonNeosMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ecd_NonNeosMember" xlink:to="lab_ecd_NonNeosMember" xlink:type="arc" order="1"/>
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