<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019fa40d-85e1-78cb-86a5-54d6f1c51b75,g:3a178aa5-0a16-4a3a-a214-69e06d3ebdab-->
<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" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.oceaneering.com/role/DocumentandEntityInformationDocument" xlink:type="simple" xlink:href="oii-20260930.xsd#DocumentandEntityInformationDocument"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/DocumentandEntityInformationDocument" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationTable_019fa40d-86c6-72ab-afbf-97a2268676c4" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_DocumentInformationTable_019fa40d-86c6-72ab-afbf-97a2268676c4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationDocumentAxis_019fa40d-86c6-7512-ae56-1fec2ad8e0cf" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationDocumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_DocumentInformationTable_019fa40d-86c6-72ab-afbf-97a2268676c4" xlink:to="loc_dei_DocumentInformationDocumentAxis_019fa40d-86c6-7512-ae56-1fec2ad8e0cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentDomain_019fa40d-86c6-7512-ae56-1fec2ad8e0cf_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_DocumentInformationDocumentAxis_019fa40d-86c6-7512-ae56-1fec2ad8e0cf" xlink:to="loc_dei_DocumentDomain_019fa40d-86c6-7512-ae56-1fec2ad8e0cf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentDomain_019fa40d-86c6-7df1-acb8-1fc81b276d9f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_DocumentInformationDocumentAxis_019fa40d-86c6-7512-ae56-1fec2ad8e0cf" xlink:to="loc_dei_DocumentDomain_019fa40d-86c6-7df1-acb8-1fc81b276d9f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus_019fa40d-86c6-70b4-a11a-a50ec7bc2753" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCurrentReportingStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_EntityCurrentReportingStatus_019fa40d-86c6-70b4-a11a-a50ec7bc2753" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019fa40d-86c6-781e-8623-1f2aa740d8b0" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_EntityRegistrantName_019fa40d-86c6-781e-8623-1f2aa740d8b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019fa40d-86c6-74fc-9618-aaf8f2bcfd18" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_EntityTaxIdentificationNumber_019fa40d-86c6-74fc-9618-aaf8f2bcfd18" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentQuarterlyReport_019fa40d-86c6-735d-9fd1-cb769d7ddf01" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentQuarterlyReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_DocumentQuarterlyReport_019fa40d-86c6-735d-9fd1-cb769d7ddf01" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019fa40d-86c6-7051-8085-279157200045" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_DocumentPeriodEndDate_019fa40d-86c6-7051-8085-279157200045" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport_019fa40d-86c6-71da-b7af-20e3f9fbbf97" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentTransitionReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_DocumentTransitionReport_019fa40d-86c6-71da-b7af-20e3f9fbbf97" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019fa40d-86c6-79eb-acfc-eca9099c507d" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent_019fa40d-86c6-7a9e-ba70-b540990e3b11" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityInteractiveDataCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_EntityInteractiveDataCurrent_019fa40d-86c6-7a9e-ba70-b540990e3b11" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory_019fa40d-86c6-7183-bad5-f0a0469f5933" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFilerCategory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_EntityFilerCategory_019fa40d-86c6-7183-bad5-f0a0469f5933" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness_019fa40d-86c6-755e-ba30-16a7ae7c7578" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntitySmallBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_EntitySmallBusiness_019fa40d-86c6-755e-ba30-16a7ae7c7578" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019fa40d-86c6-7c89-bd55-17cc525af5ae" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_EntityEmergingGrowthCompany_019fa40d-86c6-7c89-bd55-17cc525af5ae" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany_019fa40d-86c6-77cd-bb3b-eb300582db37" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityShellCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_EntityShellCompany_019fa40d-86c6-77cd-bb3b-eb300582db37" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_019fa40d-86c6-730c-ae68-89ffb684855d" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_019fa40d-86c6-730c-ae68-89ffb684855d" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019fa40d-86c6-7ccc-99c7-b0d19ddf68ad" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_EntityCentralIndexKey_019fa40d-86c6-7ccc-99c7-b0d19ddf68ad" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_019fa40d-86c6-7dd4-aa38-1f6d9fb13704" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_CurrentFiscalYearEndDate_019fa40d-86c6-7dd4-aa38-1f6d9fb13704" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus_019fa40d-86c6-7380-9b7d-c300f58452d4" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentFiscalYearFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_DocumentFiscalYearFocus_019fa40d-86c6-7380-9b7d-c300f58452d4" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus_019fa40d-86c6-7a3c-9256-424cb048bca1" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_DocumentFiscalPeriodFocus_019fa40d-86c6-7a3c-9256-424cb048bca1" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019fa40d-86c6-7574-8f75-f90b42b8db59" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_AmendmentFlag_019fa40d-86c6-7574-8f75-f90b42b8db59" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019fa40d-86c6-7bc9-a778-85556dbf3931" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fa40d-86c6-708b-ae6f-0f349395878c" xlink:to="loc_dei_DocumentType_019fa40d-86c6-7bc9-a778-85556dbf3931" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressesLineItems_019fa40d-86c6-785d-b76c-9bc719b6e118" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressesTable_019fa40d-86c6-785e-95dd-d002133b1b18" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityAddressesLineItems_019fa40d-86c6-785d-b76c-9bc719b6e118" xlink:to="loc_dei_EntityAddressesTable_019fa40d-86c6-785e-95dd-d002133b1b18" xlink:type="arc" order="2" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019fa40d-86c6-7113-a277-7a23f4b1365d" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityAddressesLineItems_019fa40d-86c6-785d-b76c-9bc719b6e118" xlink:to="loc_dei_EntityAddressAddressLine1_019fa40d-86c6-7113-a277-7a23f4b1365d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019fa40d-86c6-7920-9f8a-c0edee440eec" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityAddressesLineItems_019fa40d-86c6-785d-b76c-9bc719b6e118" xlink:to="loc_dei_EntityAddressCityOrTown_019fa40d-86c6-7920-9f8a-c0edee440eec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019fa40d-86c6-7d80-b084-1e8bd0373248" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityAddressesLineItems_019fa40d-86c6-785d-b76c-9bc719b6e118" xlink:to="loc_dei_EntityAddressStateOrProvince_019fa40d-86c6-7d80-b084-1e8bd0373248" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019fa40d-86c6-74b9-afa6-ddb092475612" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityAddressesLineItems_019fa40d-86c6-785d-b76c-9bc719b6e118" xlink:to="loc_dei_EntityAddressPostalZipCode_019fa40d-86c6-74b9-afa6-ddb092475612" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019fa40d-86c6-747d-8f0f-bf4d245fd81e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityAddressesLineItems_019fa40d-86c6-785d-b76c-9bc719b6e118" xlink:to="loc_dei_CityAreaCode_019fa40d-86c6-747d-8f0f-bf4d245fd81e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019fa40d-86c6-7642-937b-fbb7c2592034" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityAddressesLineItems_019fa40d-86c6-785d-b76c-9bc719b6e118" xlink:to="loc_dei_LocalPhoneNumber_019fa40d-86c6-7642-937b-fbb7c2592034" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019fa40d-86c6-78f3-868b-3879201e92a3" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityAddressesLineItems_019fa40d-86c6-785d-b76c-9bc719b6e118" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019fa40d-86c6-78f3-868b-3879201e92a3" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019fa40d-86c6-7860-91ca-8bd1d7e4c1b7" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityAddressesLineItems_019fa40d-86c6-785d-b76c-9bc719b6e118" xlink:to="loc_dei_EntityFileNumber_019fa40d-86c6-7860-91ca-8bd1d7e4c1b7" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityListingsLineItems_019fa40d-86c6-7a6b-8cfd-b890b977ebac" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityListingsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityListingsTable_019fa40d-86c6-76a5-912a-0b00e5ff285e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityListingsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityListingsLineItems_019fa40d-86c6-7a6b-8cfd-b890b977ebac" xlink:to="loc_dei_EntityListingsTable_019fa40d-86c6-76a5-912a-0b00e5ff285e" xlink:type="arc" order="3" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityListingsExchangeAxis_019fa40d-86c6-7ed0-8e53-010392d76362" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityListingsExchangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntityListingsTable_019fa40d-86c6-76a5-912a-0b00e5ff285e" xlink:to="loc_dei_EntityListingsExchangeAxis_019fa40d-86c6-7ed0-8e53-010392d76362" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_019fa40d-86c6-7ed0-8e53-010392d76362_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_ExchangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_EntityListingsExchangeAxis_019fa40d-86c6-7ed0-8e53-010392d76362" xlink:to="loc_dei_ExchangeDomain_019fa40d-86c6-7ed0-8e53-010392d76362_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_019fa40d-86c6-7322-b457-b6f8a59d1d9b" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_ExchangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_EntityListingsExchangeAxis_019fa40d-86c6-7ed0-8e53-010392d76362" xlink:to="loc_dei_ExchangeDomain_019fa40d-86c6-7322-b457-b6f8a59d1d9b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019fa40d-86c6-751f-a175-4a435e12c4da" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_019fa40d-86c6-7a6b-8cfd-b890b977ebac" xlink:to="loc_dei_Security12bTitle_019fa40d-86c6-751f-a175-4a435e12c4da" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019fa40d-86c6-7df8-81b9-576cc388e48e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_019fa40d-86c6-7a6b-8cfd-b890b977ebac" xlink:to="loc_dei_TradingSymbol_019fa40d-86c6-7df8-81b9-576cc388e48e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019fa40d-86c6-7fad-922b-566b824c3ff7" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_019fa40d-86c6-7a6b-8cfd-b890b977ebac" xlink:to="loc_dei_SecurityExchangeName_019fa40d-86c6-7fad-922b-566b824c3ff7" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/ConsolidatedStatementsOfCashFlowsParenthetical" xlink:type="simple" xlink:href="oii-20260930.xsd#ConsolidatedStatementsOfCashFlowsParenthetical"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/ConsolidatedStatementsOfCashFlowsParenthetical" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019fa40d-86c6-764b-aaaf-00e245af354e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019fa40d-86c6-7dc2-98f2-421a2829b4b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019fa40d-86c6-764b-aaaf-00e245af354e" xlink:to="loc_us-gaap_StatementTable_019fa40d-86c6-7dc2-98f2-421a2829b4b9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019fa40d-86c6-7f03-92c5-75bb36d61fcd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019fa40d-86c6-7dc2-98f2-421a2829b4b9" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019fa40d-86c6-7f03-92c5-75bb36d61fcd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019fa40d-86c6-7f03-92c5-75bb36d61fcd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019fa40d-86c6-7f03-92c5-75bb36d61fcd" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019fa40d-86c6-7f03-92c5-75bb36d61fcd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019fa40d-86c6-7067-9f1a-c9ea524b87f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019fa40d-86c6-7f03-92c5-75bb36d61fcd" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019fa40d-86c6-7067-9f1a-c9ea524b87f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_019fa40d-86c6-76a0-86a6-7178fb699412" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019fa40d-86c6-7067-9f1a-c9ea524b87f2" xlink:to="loc_us-gaap_SeniorNotesMember_019fa40d-86c6-76a0-86a6-7178fb699412" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019fa40d-86c7-7939-89ee-978de12ef4b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fa40d-86c6-764b-aaaf-00e245af354e" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019fa40d-86c7-7939-89ee-978de12ef4b5" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/ConsolidatedStatementsofEquity" xlink:type="simple" xlink:href="oii-20260930.xsd#ConsolidatedStatementsofEquity"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/ConsolidatedStatementsofEquity" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019fa40d-86c7-70ab-b25b-3485004042ba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019fa40d-86c7-7f6f-85e4-02becd7445bf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019fa40d-86c7-70ab-b25b-3485004042ba" xlink:to="loc_us-gaap_StatementTable_019fa40d-86c7-7f6f-85e4-02becd7445bf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019fa40d-86c7-7d01-b259-10b41b4fb4ea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019fa40d-86c7-7f6f-85e4-02becd7445bf" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019fa40d-86c7-7d01-b259-10b41b4fb4ea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019fa40d-86c7-7d01-b259-10b41b4fb4ea_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019fa40d-86c7-7d01-b259-10b41b4fb4ea" xlink:to="loc_us-gaap_EquityComponentDomain_019fa40d-86c7-7d01-b259-10b41b4fb4ea_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019fa40d-86c7-7b7e-980f-674ebbf89b11" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019fa40d-86c7-7d01-b259-10b41b4fb4ea" xlink:to="loc_us-gaap_EquityComponentDomain_019fa40d-86c7-7b7e-980f-674ebbf89b11" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019fa40d-86c7-743a-819e-943c5b4a27f9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019fa40d-86c7-7b7e-980f-674ebbf89b11" xlink:to="loc_us-gaap_CommonStockMember_019fa40d-86c7-743a-819e-943c5b4a27f9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_019fa40d-86c7-7253-911e-2b0f660e4302" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019fa40d-86c7-7b7e-980f-674ebbf89b11" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_019fa40d-86c7-7253-911e-2b0f660e4302" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_019fa40d-86c7-7de7-98a3-ad9ffcfe7a54" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019fa40d-86c7-7b7e-980f-674ebbf89b11" xlink:to="loc_us-gaap_RetainedEarningsMember_019fa40d-86c7-7de7-98a3-ad9ffcfe7a54" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_019fa40d-86c7-7bf7-bf4e-f3ab76fce510" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019fa40d-86c7-7b7e-980f-674ebbf89b11" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_019fa40d-86c7-7bf7-bf4e-f3ab76fce510" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ParentMember_019fa40d-86c7-7d93-a7c3-ff346d787211" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019fa40d-86c7-7b7e-980f-674ebbf89b11" xlink:to="loc_us-gaap_ParentMember_019fa40d-86c7-7d93-a7c3-ff346d787211" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_019fa40d-86c7-785a-bf97-bfdd88a9cc9a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019fa40d-86c7-7b7e-980f-674ebbf89b11" xlink:to="loc_us-gaap_NoncontrollingInterestMember_019fa40d-86c7-785a-bf97-bfdd88a9cc9a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_019fa40d-86c7-7418-82f2-04baf21311c4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019fa40d-86c7-7b7e-980f-674ebbf89b11" xlink:to="loc_us-gaap_TreasuryStockCommonMember_019fa40d-86c7-7418-82f2-04baf21311c4" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019fa40d-86c7-7fc2-8a9e-88e5d941f31d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019fa40d-86c7-7f6f-85e4-02becd7445bf" xlink:to="loc_us-gaap_AwardTypeAxis_019fa40d-86c7-7fc2-8a9e-88e5d941f31d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019fa40d-86c7-7fc2-8a9e-88e5d941f31d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019fa40d-86c7-7fc2-8a9e-88e5d941f31d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019fa40d-86c7-7fc2-8a9e-88e5d941f31d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019fa40d-86c7-728c-a719-f728b6e0ee12" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019fa40d-86c7-7fc2-8a9e-88e5d941f31d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019fa40d-86c7-728c-a719-f728b6e0ee12" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_019fa40d-86c7-7071-a6d1-5c36b91b6c4d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019fa40d-86c7-728c-a719-f728b6e0ee12" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_019fa40d-86c7-7071-a6d1-5c36b91b6c4d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_019fa40d-86c7-7ad0-911f-f505861aedf4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019fa40d-86c7-728c-a719-f728b6e0ee12" xlink:to="loc_us-gaap_RestrictedStockMember_019fa40d-86c7-7ad0-911f-f505861aedf4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019fa40d-86c7-7aeb-bc8b-1a1b3a29fafd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019fa40d-86c7-7f6f-85e4-02becd7445bf" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019fa40d-86c7-7aeb-bc8b-1a1b3a29fafd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_019fa40d-86c7-7aeb-bc8b-1a1b3a29fafd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019fa40d-86c7-7aeb-bc8b-1a1b3a29fafd" xlink:to="loc_us-gaap_TypeOfAdoptionMember_019fa40d-86c7-7aeb-bc8b-1a1b3a29fafd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_019fa40d-86c7-7058-844c-f135035d71cf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019fa40d-86c7-7aeb-bc8b-1a1b3a29fafd" xlink:to="loc_us-gaap_TypeOfAdoptionMember_019fa40d-86c7-7058-844c-f135035d71cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForCreditLossMember_019fa40d-86c7-763e-8c7f-90b9b0dbc182" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllowanceForCreditLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_019fa40d-86c7-7058-844c-f135035d71cf" xlink:to="loc_us-gaap_AllowanceForCreditLossMember_019fa40d-86c7-763e-8c7f-90b9b0dbc182" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019fa40d-86c7-7f05-93ac-e09e0fcd8433" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019fa40d-86c7-7f6f-85e4-02becd7445bf" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019fa40d-86c7-7f05-93ac-e09e0fcd8433" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-7f05-93ac-e09e0fcd8433_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019fa40d-86c7-7f05-93ac-e09e0fcd8433" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-7f05-93ac-e09e0fcd8433_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-733c-a94a-ad01d5718baa" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019fa40d-86c7-7f05-93ac-e09e0fcd8433" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-733c-a94a-ad01d5718baa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_019fa40d-86c7-74b4-a778-64991383fab1" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-733c-a94a-ad01d5718baa" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_019fa40d-86c7-74b4-a778-64991383fab1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-7412-b624-1048aa54aa3d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019fa40d-86c7-7f6f-85e4-02becd7445bf" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-7412-b624-1048aa54aa3d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-7412-b624-1048aa54aa3d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-7412-b624-1048aa54aa3d" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-7412-b624-1048aa54aa3d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-77f3-a1f9-c251bedcc7f0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-7412-b624-1048aa54aa3d" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-77f3-a1f9-c251bedcc7f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceReceivablesMember_019fa40d-86c7-787d-b2d0-16f08c879fa6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-77f3-a1f9-c251bedcc7f0" xlink:to="loc_us-gaap_FinanceReceivablesMember_019fa40d-86c7-787d-b2d0-16f08c879fa6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fa40d-86c7-7423-a1d4-a3a4dd231ad3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fa40d-86c7-70ab-b25b-3485004042ba" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fa40d-86c7-7423-a1d4-a3a4dd231ad3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019fa40d-86c7-757e-9e37-0b8f6beaaea7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fa40d-86c7-7423-a1d4-a3a4dd231ad3" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019fa40d-86c7-757e-9e37-0b8f6beaaea7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_019fa40d-86c7-77d0-843d-85ddc2eae6fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fa40d-86c7-7423-a1d4-a3a4dd231ad3" xlink:to="loc_us-gaap_ProfitLoss_019fa40d-86c7-77d0-843d-85ddc2eae6fe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_019fa40d-86c7-73f0-a32f-fa5fb34632bf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fa40d-86c7-7423-a1d4-a3a4dd231ad3" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_019fa40d-86c7-73f0-a32f-fa5fb34632bf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019fa40d-86c7-7857-a5f7-a33156a073fa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fa40d-86c7-7423-a1d4-a3a4dd231ad3" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019fa40d-86c7-7857-a5f7-a33156a073fa" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockExpense_019fa40d-86c7-7a9b-93e4-1d3c8b2889ec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedStockExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fa40d-86c7-7423-a1d4-a3a4dd231ad3" xlink:to="loc_us-gaap_RestrictedStockExpense_019fa40d-86c7-7a9b-93e4-1d3c8b2889ec" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_019fa40d-86c7-79c6-b9a0-526ecfa945c5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fa40d-86c7-7423-a1d4-a3a4dd231ad3" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_019fa40d-86c7-79c6-b9a0-526ecfa945c5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_019fa40d-86c7-7b83-8630-75658c090a97" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fa40d-86c7-7423-a1d4-a3a4dd231ad3" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_019fa40d-86c7-7b83-8630-75658c090a97" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax_019fa40d-86c7-7608-89bd-7823e515e2aa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fa40d-86c7-7423-a1d4-a3a4dd231ad3" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax_019fa40d-86c7-7608-89bd-7823e515e2aa" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019fa40d-86c7-76e3-8f85-c656411a971c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityOther_019fa40d-86c7-7c9d-ad97-98c32ef12523" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fa40d-86c7-7423-a1d4-a3a4dd231ad3" xlink:to="loc_us-gaap_StockholdersEquityOther_019fa40d-86c7-7c9d-ad97-98c32ef12523" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_019fa40d-86c7-706e-acd7-811a41f9e7b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fa40d-86c7-70ab-b25b-3485004042ba" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_019fa40d-86c7-706e-acd7-811a41f9e7b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_019fa40d-86c7-7f18-8306-38785872fdeb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fa40d-86c7-70ab-b25b-3485004042ba" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_019fa40d-86c7-7f18-8306-38785872fdeb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_019fa40d-86c7-7263-af43-a5bdec5c91ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fa40d-86c7-70ab-b25b-3485004042ba" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_019fa40d-86c7-7263-af43-a5bdec5c91ca" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019fa40d-86c7-728d-8c34-5e592e237a34" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fa40d-86c7-70ab-b25b-3485004042ba" xlink:to="loc_us-gaap_StockholdersEquity_019fa40d-86c7-728d-8c34-5e592e237a34" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019fa40d-86c7-7c3d-ab34-b194304eda11" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fa40d-86c7-70ab-b25b-3485004042ba" xlink:to="loc_us-gaap_NetIncomeLoss_019fa40d-86c7-7c3d-ab34-b194304eda11" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_019fa40d-86c7-7885-be51-06b749914a0e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fa40d-86c7-70ab-b25b-3485004042ba" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_019fa40d-86c7-7885-be51-06b749914a0e" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/AllowanceforCreditLossStatement" xlink:type="simple" xlink:href="oii-20260930.xsd#AllowanceforCreditLossStatement"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/AllowanceforCreditLossStatement" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7dd5-8fdf-58d04552bfe2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fa40d-86c7-7852-9348-21ba5c137a2d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7dd5-8fdf-58d04552bfe2" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fa40d-86c7-7852-9348-21ba5c137a2d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-7f71-86fa-66bef60f8d6c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fa40d-86c7-7852-9348-21ba5c137a2d" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-7f71-86fa-66bef60f8d6c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-7f71-86fa-66bef60f8d6c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-7f71-86fa-66bef60f8d6c" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-7f71-86fa-66bef60f8d6c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-7a3d-bbcd-6a68e49dacec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-7f71-86fa-66bef60f8d6c" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-7a3d-bbcd-6a68e49dacec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableMember_019fa40d-86c7-78a8-aa7b-95daa937f587" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-7a3d-bbcd-6a68e49dacec" xlink:to="loc_us-gaap_AccountsReceivableMember_019fa40d-86c7-78a8-aa7b-95daa937f587" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019fa40d-86c7-7665-b7e1-9a8bb5209470" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fa40d-86c7-7852-9348-21ba5c137a2d" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019fa40d-86c7-7665-b7e1-9a8bb5209470" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-7665-b7e1-9a8bb5209470_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019fa40d-86c7-7665-b7e1-9a8bb5209470" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-7665-b7e1-9a8bb5209470_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-7728-86d3-20525c3238a6" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019fa40d-86c7-7665-b7e1-9a8bb5209470" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-7728-86d3-20525c3238a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_019fa40d-86c7-727c-9148-a11efe183451" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-7728-86d3-20525c3238a6" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_019fa40d-86c7-727c-9148-a11efe183451" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019fa40d-86c7-71bc-8fae-dcc0c0c81b11" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7dd5-8fdf-58d04552bfe2" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019fa40d-86c7-71bc-8fae-dcc0c0c81b11" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_019fa40d-86c7-74a9-a93d-740236486243" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7dd5-8fdf-58d04552bfe2" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_019fa40d-86c7-74a9-a93d-740236486243" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_019fa40d-86c7-711c-ab01-621312634960" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7dd5-8fdf-58d04552bfe2" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_019fa40d-86c7-711c-ab01-621312634960" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/AccountingPoliciesDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#AccountingPoliciesDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/AccountingPoliciesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7fba-969c-6571ca6c7ed5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fa40d-86c7-7d98-a0db-6c6fbb31f563" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7fba-969c-6571ca6c7ed5" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fa40d-86c7-7d98-a0db-6c6fbb31f563" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019fa40d-86c7-7ce0-a319-75741217399f" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fa40d-86c7-7d98-a0db-6c6fbb31f563" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019fa40d-86c7-7ce0-a319-75741217399f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-7ce0-a319-75741217399f_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019fa40d-86c7-7ce0-a319-75741217399f" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-7ce0-a319-75741217399f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-708b-9e8d-9c70fc1026aa" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019fa40d-86c7-7ce0-a319-75741217399f" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-708b-9e8d-9c70fc1026aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_019fa40d-86c7-72ac-b1bf-24ee4ccedd46" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-708b-9e8d-9c70fc1026aa" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_019fa40d-86c7-72ac-b1bf-24ee4ccedd46" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-731b-87be-a982eb30f622" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fa40d-86c7-7d98-a0db-6c6fbb31f563" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-731b-87be-a982eb30f622" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-731b-87be-a982eb30f622_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-731b-87be-a982eb30f622" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-731b-87be-a982eb30f622_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-700a-ae47-9a80646c20eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-731b-87be-a982eb30f622" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-700a-ae47-9a80646c20eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableMember_019fa40d-86c7-7bbe-bc63-afb98517c64d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-700a-ae47-9a80646c20eb" xlink:to="loc_us-gaap_AccountsReceivableMember_019fa40d-86c7-7bbe-bc63-afb98517c64d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019fa40d-86c7-7680-b901-9a33256c033f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7fba-969c-6571ca6c7ed5" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019fa40d-86c7-7680-b901-9a33256c033f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestReceivable_019fa40d-86c7-79e8-851d-8a0265ad124a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7fba-969c-6571ca6c7ed5" xlink:to="loc_us-gaap_InterestReceivable_019fa40d-86c7-79e8-851d-8a0265ad124a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_019fa40d-86c7-777d-a4ff-9695cb2bceca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7fba-969c-6571ca6c7ed5" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_019fa40d-86c7-777d-a4ff-9695cb2bceca" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_019fa40d-86c7-76df-b97d-07dde70c09cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7fba-969c-6571ca6c7ed5" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_019fa40d-86c7-76df-b97d-07dde70c09cb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_019fa40d-86c7-7a08-9c4a-73821f076c44" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7fba-969c-6571ca6c7ed5" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_019fa40d-86c7-7a08-9c4a-73821f076c44" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsAndFinancingReceivableAllowanceForCreditLoss_019fa40d-86c7-7f44-b88f-d8a7300b20c2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsAndFinancingReceivableAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7fba-969c-6571ca6c7ed5" xlink:to="loc_us-gaap_AccountsAndFinancingReceivableAllowanceForCreditLoss_019fa40d-86c7-7f44-b88f-d8a7300b20c2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_019fa40d-86c7-7f31-9a36-7d353e766ecf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7fba-969c-6571ca6c7ed5" xlink:to="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_019fa40d-86c7-7f31-9a36-7d353e766ecf" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/SummaryOfMajorAccountingPoliciesAdditionalInformationDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#SummaryOfMajorAccountingPoliciesAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/SummaryOfMajorAccountingPoliciesAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019fa40d-86c7-716c-9649-467afa00e755" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019fa40d-86c7-716c-9649-467afa00e755" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019fa40d-86c7-73bc-a932-619db06115d3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019fa40d-86c7-716c-9649-467afa00e755" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019fa40d-86c7-73bc-a932-619db06115d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019fa40d-86c7-73bc-a932-619db06115d3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019fa40d-86c7-73bc-a932-619db06115d3" xlink:to="loc_us-gaap_EquityComponentDomain_019fa40d-86c7-73bc-a932-619db06115d3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019fa40d-86c7-7aa9-b736-b258c0646aab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019fa40d-86c7-73bc-a932-619db06115d3" xlink:to="loc_us-gaap_EquityComponentDomain_019fa40d-86c7-7aa9-b736-b258c0646aab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_019fa40d-86c7-77f6-b24e-7ab6ddb2e644" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019fa40d-86c7-7aa9-b736-b258c0646aab" xlink:to="loc_us-gaap_RetainedEarningsMember_019fa40d-86c7-77f6-b24e-7ab6ddb2e644" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019fa40d-86c7-7c36-a669-60a20fc6f014" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019fa40d-86c7-716c-9649-467afa00e755" xlink:to="loc_srt_RangeAxis_019fa40d-86c7-7c36-a669-60a20fc6f014" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa40d-86c7-7c36-a669-60a20fc6f014_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019fa40d-86c7-7c36-a669-60a20fc6f014" xlink:to="loc_srt_RangeMember_019fa40d-86c7-7c36-a669-60a20fc6f014_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa40d-86c7-7319-b56a-8b54e054b393" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019fa40d-86c7-7c36-a669-60a20fc6f014" xlink:to="loc_srt_RangeMember_019fa40d-86c7-7319-b56a-8b54e054b393" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019fa40d-86c7-7f94-b1f4-cc773849e641" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fa40d-86c7-7319-b56a-8b54e054b393" xlink:to="loc_srt_MaximumMember_019fa40d-86c7-7f94-b1f4-cc773849e641" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019fa40d-86c7-7a32-a33f-846a4aab85de" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fa40d-86c7-7319-b56a-8b54e054b393" xlink:to="loc_srt_MinimumMember_019fa40d-86c7-7a32-a33f-846a4aab85de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-7bb7-a4dc-bacd8487fa87" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019fa40d-86c7-716c-9649-467afa00e755" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-7bb7-a4dc-bacd8487fa87" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-7bb7-a4dc-bacd8487fa87_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-7bb7-a4dc-bacd8487fa87" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-7bb7-a4dc-bacd8487fa87_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-7e0f-bd63-fce122a72e75" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-7bb7-a4dc-bacd8487fa87" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-7e0f-bd63-fce122a72e75" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableMember_019fa40d-86c7-717d-a52f-0b43d26f9097" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-7e0f-bd63-fce122a72e75" xlink:to="loc_us-gaap_AccountsReceivableMember_019fa40d-86c7-717d-a52f-0b43d26f9097" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_Rightofuseassetimpairment_019fa40d-86c7-76ca-92b1-b30781050a8f" xlink:href="oii-20260930.xsd#oii_Rightofuseassetimpairment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_oii_Rightofuseassetimpairment_019fa40d-86c7-76ca-92b1-b30781050a8f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_Impairmentpropertyplantequipment_019fa40d-86c7-7199-ad75-c99278cb5b74" xlink:href="oii-20260930.xsd#oii_Impairmentpropertyplantequipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_oii_Impairmentpropertyplantequipment_019fa40d-86c7-7199-ad75-c99278cb5b74" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_IntangibleAssetsImpairments_019fa40d-86c7-7126-a936-58550a1f0c8e" xlink:href="oii-20260930.xsd#oii_IntangibleAssetsImpairments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_oii_IntangibleAssetsImpairments_019fa40d-86c7-7126-a936-58550a1f0c8e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse_019fa40d-86c7-7e50-bacd-33570f0c6463" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ImpairmentOfLongLivedAssetsHeldForUse"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse_019fa40d-86c7-7e50-bacd-33570f0c6463" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_019fa40d-86c7-7c9a-98f2-12aa5964ce03" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_us-gaap_OperatingLeaseLiability_019fa40d-86c7-7c9a-98f2-12aa5964ce03" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_019fa40d-86c7-7b1b-8181-da098ef01fb2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_019fa40d-86c7-7b1b-8181-da098ef01fb2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_019fa40d-86c7-71a1-9793-f4168a42ed7f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_019fa40d-86c7-71a1-9793-f4168a42ed7f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_ConsolidationLessthanWhollyOwnedSubsidiaryParentOwnershipInterestThresholdforConsolidationPercentage_019fa40d-86c7-7104-a6b1-30368074dd1b" xlink:href="oii-20260930.xsd#oii_ConsolidationLessthanWhollyOwnedSubsidiaryParentOwnershipInterestThresholdforConsolidationPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_oii_ConsolidationLessthanWhollyOwnedSubsidiaryParentOwnershipInterestThresholdforConsolidationPercentage_019fa40d-86c7-7104-a6b1-30368074dd1b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_019fa40d-86c7-70ee-a23c-15141da54841" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_019fa40d-86c7-70ee-a23c-15141da54841" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestCostsCapitalized_019fa40d-86c7-7cdd-88b6-1b158268b26c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestCostsCapitalized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_us-gaap_InterestCostsCapitalized_019fa40d-86c7-7cdd-88b6-1b158268b26c" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_OperatingLeasesOperatingLeaseTerm_019fa40d-86c7-732b-9da2-be0440878218" xlink:href="oii-20260930.xsd#oii_OperatingLeasesOperatingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_oii_OperatingLeasesOperatingLeaseTerm_019fa40d-86c7-732b-9da2-be0440878218" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_019fa40d-86c7-7d5a-8c94-05b0fcb79d36" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_019fa40d-86c7-7d5a-8c94-05b0fcb79d36" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentAdditionalInformation_019fa40d-86c7-7885-8fd0-4eecbcbdca57" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentAdditionalInformation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_us-gaap_EquityMethodInvestmentAdditionalInformation_019fa40d-86c7-7885-8fd0-4eecbcbdca57" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseTermOfContract_019fa40d-86c7-7b6b-8a3b-1354fc490f51" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_us-gaap_LesseeOperatingLeaseTermOfContract_019fa40d-86c7-7b6b-8a3b-1354fc490f51" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_FinancingReceivableAllowanceForCreditLossesEvaluationPeriod_019fa40d-86c7-738d-a577-c38926574a31" xlink:href="oii-20260930.xsd#oii_FinancingReceivableAllowanceForCreditLossesEvaluationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_oii_FinancingReceivableAllowanceForCreditLossesEvaluationPeriod_019fa40d-86c7-738d-a577-c38926574a31" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_019fa40d-86c7-7200-988a-64a15c760c17" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_019fa40d-86c7-7200-988a-64a15c760c17" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressGross_019fa40d-86c7-7efe-881b-8b5ab385401f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConstructionInProgressGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_us-gaap_ConstructionInProgressGross_019fa40d-86c7-7efe-881b-8b5ab385401f" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedComputerSoftwarePeriodIncreaseDecrease_019fa40d-86c7-7fec-b5af-b18d9f8b433b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedComputerSoftwarePeriodIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-77f1-9039-5efd28fd4b12" xlink:to="loc_us-gaap_CapitalizedComputerSoftwarePeriodIncreaseDecrease_019fa40d-86c7-7fec-b5af-b18d9f8b433b" xlink:type="arc" order="17"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/SummaryOfMajorAccountingPoliciesGoodwillImpairmentDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#SummaryOfMajorAccountingPoliciesGoodwillImpairmentDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/SummaryOfMajorAccountingPoliciesGoodwillImpairmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_019fa40d-86c7-73d5-9876-c78384a52310" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_019fa40d-86c7-7de9-8e08-52cb27c5c49c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_019fa40d-86c7-73d5-9876-c78384a52310" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_019fa40d-86c7-7de9-8e08-52cb27c5c49c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019fa40d-86c7-7221-a09c-0f8a46781730" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_019fa40d-86c7-7de9-8e08-52cb27c5c49c" xlink:to="loc_srt_ConsolidationItemsAxis_019fa40d-86c7-7221-a09c-0f8a46781730" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019fa40d-86c7-7221-a09c-0f8a46781730_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019fa40d-86c7-7221-a09c-0f8a46781730" xlink:to="loc_srt_ConsolidationItemsDomain_019fa40d-86c7-7221-a09c-0f8a46781730_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019fa40d-86c7-7ef8-9693-3e6431c2dc30" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019fa40d-86c7-7221-a09c-0f8a46781730" xlink:to="loc_srt_ConsolidationItemsDomain_019fa40d-86c7-7ef8-9693-3e6431c2dc30" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-7d7d-ac64-51e8ba85788a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_019fa40d-86c7-7de9-8e08-52cb27c5c49c" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-7d7d-ac64-51e8ba85788a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-86c7-7d7d-ac64-51e8ba85788a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-7d7d-ac64-51e8ba85788a" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-86c7-7d7d-ac64-51e8ba85788a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-86c7-7047-a445-73d79afdf192" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-7d7d-ac64-51e8ba85788a" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-86c7-7047-a445-73d79afdf192" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SubseaProductsMember_019fa40d-86c7-7eec-8f85-6efe623898b9" xlink:href="oii-20260930.xsd#oii_SubseaProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-86c7-7047-a445-73d79afdf192" xlink:to="loc_oii_SubseaProductsMember_019fa40d-86c7-7eec-8f85-6efe623898b9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SubseaProjectsMember_019fa40d-86c7-75db-8ed3-460da7e8a96a" xlink:href="oii-20260930.xsd#oii_SubseaProjectsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-86c7-7047-a445-73d79afdf192" xlink:to="loc_oii_SubseaProjectsMember_019fa40d-86c7-75db-8ed3-460da7e8a96a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_AssetIntegrityMember_019fa40d-86c7-70d3-855c-b9cd3c773f08" xlink:href="oii-20260930.xsd#oii_AssetIntegrityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-86c7-7047-a445-73d79afdf192" xlink:to="loc_oii_AssetIntegrityMember_019fa40d-86c7-70d3-855c-b9cd3c773f08" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_AdvancedTechnologiesMember_019fa40d-86c7-7f77-b6c8-098bca0bd3aa" xlink:href="oii-20260930.xsd#oii_AdvancedTechnologiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-86c7-7047-a445-73d79afdf192" xlink:to="loc_oii_AdvancedTechnologiesMember_019fa40d-86c7-7f77-b6c8-098bca0bd3aa" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019fa40d-86c7-7347-9cfe-a894f34dac40" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfIncomeLocationBalanceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_019fa40d-86c7-7de9-8e08-52cb27c5c49c" xlink:to="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019fa40d-86c7-7347-9cfe-a894f34dac40" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitAxis_019fa40d-86c7-7505-97d3-4d8c461357e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReportingUnitAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_019fa40d-86c7-7de9-8e08-52cb27c5c49c" xlink:to="loc_us-gaap_ReportingUnitAxis_019fa40d-86c7-7505-97d3-4d8c461357e3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitDomain_019fa40d-86c7-7505-97d3-4d8c461357e3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReportingUnitDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReportingUnitAxis_019fa40d-86c7-7505-97d3-4d8c461357e3" xlink:to="loc_us-gaap_ReportingUnitDomain_019fa40d-86c7-7505-97d3-4d8c461357e3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitDomain_019fa40d-86c7-7f7f-8d9b-baf642933b12" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReportingUnitDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReportingUnitAxis_019fa40d-86c7-7505-97d3-4d8c461357e3" xlink:to="loc_us-gaap_ReportingUnitDomain_019fa40d-86c7-7f7f-8d9b-baf642933b12" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_019fa40d-86c7-71d1-b964-995ca5ba1d7b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_019fa40d-86c7-73d5-9876-c78384a52310" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_019fa40d-86c7-71d1-b964-995ca5ba1d7b" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/SummaryOfMajorAccountingPoliciesGoodwillImpairmentDetails_1" xlink:type="simple" xlink:href="oii-20260930.xsd#SummaryOfMajorAccountingPoliciesGoodwillImpairmentDetails_1"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/SummaryOfMajorAccountingPoliciesGoodwillImpairmentDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_019fa40d-86c7-73d5-9876-c78384a52310" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_019fa40d-86c7-7de9-8e08-52cb27c5c49c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_019fa40d-86c7-73d5-9876-c78384a52310" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_019fa40d-86c7-7de9-8e08-52cb27c5c49c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019fa40d-86c7-7221-a09c-0f8a46781730" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_019fa40d-86c7-7de9-8e08-52cb27c5c49c" xlink:to="loc_srt_ConsolidationItemsAxis_019fa40d-86c7-7221-a09c-0f8a46781730" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019fa40d-86c7-7221-a09c-0f8a46781730_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019fa40d-86c7-7221-a09c-0f8a46781730" xlink:to="loc_srt_ConsolidationItemsDomain_019fa40d-86c7-7221-a09c-0f8a46781730_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019fa40d-86c7-7ef8-9693-3e6431c2dc30" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019fa40d-86c7-7221-a09c-0f8a46781730" xlink:to="loc_srt_ConsolidationItemsDomain_019fa40d-86c7-7ef8-9693-3e6431c2dc30" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-7d7d-ac64-51e8ba85788a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_019fa40d-86c7-7de9-8e08-52cb27c5c49c" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-7d7d-ac64-51e8ba85788a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-86c7-7d7d-ac64-51e8ba85788a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-7d7d-ac64-51e8ba85788a" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-86c7-7d7d-ac64-51e8ba85788a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-86c7-7047-a445-73d79afdf192" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-7d7d-ac64-51e8ba85788a" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-86c7-7047-a445-73d79afdf192" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SubseaProductsMember_019fa40d-86c7-7eec-8f85-6efe623898b9" xlink:href="oii-20260930.xsd#oii_SubseaProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-86c7-7047-a445-73d79afdf192" xlink:to="loc_oii_SubseaProductsMember_019fa40d-86c7-7eec-8f85-6efe623898b9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SubseaProjectsMember_019fa40d-86c7-75db-8ed3-460da7e8a96a" xlink:href="oii-20260930.xsd#oii_SubseaProjectsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-86c7-7047-a445-73d79afdf192" xlink:to="loc_oii_SubseaProjectsMember_019fa40d-86c7-75db-8ed3-460da7e8a96a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_AssetIntegrityMember_019fa40d-86c7-70d3-855c-b9cd3c773f08" xlink:href="oii-20260930.xsd#oii_AssetIntegrityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-86c7-7047-a445-73d79afdf192" xlink:to="loc_oii_AssetIntegrityMember_019fa40d-86c7-70d3-855c-b9cd3c773f08" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_AdvancedTechnologiesMember_019fa40d-86c7-7f77-b6c8-098bca0bd3aa" xlink:href="oii-20260930.xsd#oii_AdvancedTechnologiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-86c7-7047-a445-73d79afdf192" xlink:to="loc_oii_AdvancedTechnologiesMember_019fa40d-86c7-7f77-b6c8-098bca0bd3aa" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitAxis_019fa40d-86c7-7505-97d3-4d8c461357e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReportingUnitAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_019fa40d-86c7-7de9-8e08-52cb27c5c49c" xlink:to="loc_us-gaap_ReportingUnitAxis_019fa40d-86c7-7505-97d3-4d8c461357e3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitDomain_019fa40d-86c7-7505-97d3-4d8c461357e3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReportingUnitDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReportingUnitAxis_019fa40d-86c7-7505-97d3-4d8c461357e3" xlink:to="loc_us-gaap_ReportingUnitDomain_019fa40d-86c7-7505-97d3-4d8c461357e3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitDomain_019fa40d-86c7-7f7f-8d9b-baf642933b12" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReportingUnitDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReportingUnitAxis_019fa40d-86c7-7505-97d3-4d8c461357e3" xlink:to="loc_us-gaap_ReportingUnitDomain_019fa40d-86c7-7f7f-8d9b-baf642933b12" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_019fa40d-86c7-71d1-b964-995ca5ba1d7b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_019fa40d-86c7-73d5-9876-c78384a52310" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_019fa40d-86c7-71d1-b964-995ca5ba1d7b" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/SummaryOfMajorAccountingPoliciesAllowanceforcreditlossesDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#SummaryOfMajorAccountingPoliciesAllowanceforcreditlossesDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/SummaryOfMajorAccountingPoliciesAllowanceforcreditlossesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7a36-8115-2663fdeac4bb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fa40d-86c7-7195-867c-56487d2c6aba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7a36-8115-2663fdeac4bb" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fa40d-86c7-7195-867c-56487d2c6aba" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019fa40d-86c7-7424-8e59-95d70ff6544b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fa40d-86c7-7195-867c-56487d2c6aba" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019fa40d-86c7-7424-8e59-95d70ff6544b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_019fa40d-86c7-7424-8e59-95d70ff6544b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019fa40d-86c7-7424-8e59-95d70ff6544b" xlink:to="loc_us-gaap_TypeOfAdoptionMember_019fa40d-86c7-7424-8e59-95d70ff6544b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_019fa40d-86c7-76d5-b7f0-a5ea5bee62bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019fa40d-86c7-7424-8e59-95d70ff6544b" xlink:to="loc_us-gaap_TypeOfAdoptionMember_019fa40d-86c7-76d5-b7f0-a5ea5bee62bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForCreditLossMember_019fa40d-86c7-7c3e-86c6-4cbf61892423" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllowanceForCreditLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_019fa40d-86c7-76d5-b7f0-a5ea5bee62bd" xlink:to="loc_us-gaap_AllowanceForCreditLossMember_019fa40d-86c7-7c3e-86c6-4cbf61892423" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-718b-a41a-4b0a4e534764" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fa40d-86c7-7195-867c-56487d2c6aba" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-718b-a41a-4b0a4e534764" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-718b-a41a-4b0a4e534764_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-718b-a41a-4b0a4e534764" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-718b-a41a-4b0a4e534764_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-7ea4-99cb-a6905bd7a0e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-86c7-718b-a41a-4b0a4e534764" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-7ea4-99cb-a6905bd7a0e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableMember_019fa40d-86c7-7072-9dfa-cc1dab225768" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-7ea4-99cb-a6905bd7a0e4" xlink:to="loc_us-gaap_AccountsReceivableMember_019fa40d-86c7-7072-9dfa-cc1dab225768" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceReceivablesMember_019fa40d-86c7-7665-8e99-e352cd5c7740" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-86c7-7ea4-99cb-a6905bd7a0e4" xlink:to="loc_us-gaap_FinanceReceivablesMember_019fa40d-86c7-7665-8e99-e352cd5c7740" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019fa40d-86c7-7b3a-aa44-97548aa221e2" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fa40d-86c7-7195-867c-56487d2c6aba" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019fa40d-86c7-7b3a-aa44-97548aa221e2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-7b3a-aa44-97548aa221e2_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019fa40d-86c7-7b3a-aa44-97548aa221e2" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-7b3a-aa44-97548aa221e2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-7285-aeeb-73086e1e89ed" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019fa40d-86c7-7b3a-aa44-97548aa221e2" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-7285-aeeb-73086e1e89ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_019fa40d-86c7-7ab8-8cbf-3181f8ff8b08" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019fa40d-86c7-7285-aeeb-73086e1e89ed" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_019fa40d-86c7-7ab8-8cbf-3181f8ff8b08" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019fa40d-86c7-7775-89d7-495004a29073" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fa40d-86c7-7195-867c-56487d2c6aba" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019fa40d-86c7-7775-89d7-495004a29073" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_019fa40d-86c7-7775-89d7-495004a29073_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019fa40d-86c7-7775-89d7-495004a29073" xlink:to="loc_us-gaap_ReceivableTypeDomain_019fa40d-86c7-7775-89d7-495004a29073_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_019fa40d-86c7-7010-8578-ac91e487d689" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019fa40d-86c7-7775-89d7-495004a29073" xlink:to="loc_us-gaap_ReceivableTypeDomain_019fa40d-86c7-7010-8578-ac91e487d689" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceReceivablesMember_019fa40d-86c7-7da6-8219-6c50782403d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_019fa40d-86c7-7010-8578-ac91e487d689" xlink:to="loc_us-gaap_FinanceReceivablesMember_019fa40d-86c7-7da6-8219-6c50782403d4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_019fa40d-86c7-725c-9bf7-177682c5a970" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7a36-8115-2663fdeac4bb" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_019fa40d-86c7-725c-9bf7-177682c5a970" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_019fa40d-86c7-7468-aa8c-6badc55eeaf4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7a36-8115-2663fdeac4bb" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_019fa40d-86c7-7468-aa8c-6badc55eeaf4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019fa40d-86c7-7760-9075-8c1e6e6b013b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7a36-8115-2663fdeac4bb" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019fa40d-86c7-7760-9075-8c1e6e6b013b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestReceivable_019fa40d-86c7-7fe4-bbd3-35ba606dc2ce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7a36-8115-2663fdeac4bb" xlink:to="loc_us-gaap_InterestReceivable_019fa40d-86c7-7fe4-bbd3-35ba606dc2ce" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_019fa40d-86c7-75d1-bc17-dc5d728d4899" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7a36-8115-2663fdeac4bb" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_019fa40d-86c7-75d1-bc17-dc5d728d4899" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_FinancingReceivableAllowanceForCreditLossesEvaluationPeriod_019fa40d-86c7-75c9-9d66-d97e071766ab" xlink:href="oii-20260930.xsd#oii_FinancingReceivableAllowanceForCreditLossesEvaluationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7a36-8115-2663fdeac4bb" xlink:to="loc_oii_FinancingReceivableAllowanceForCreditLossesEvaluationPeriod_019fa40d-86c7-75c9-9d66-d97e071766ab" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsAndFinancingReceivableAllowanceForCreditLoss_019fa40d-86c7-783f-948c-7e8a719a4868" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsAndFinancingReceivableAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7a36-8115-2663fdeac4bb" xlink:to="loc_us-gaap_AccountsAndFinancingReceivableAllowanceForCreditLoss_019fa40d-86c7-783f-948c-7e8a719a4868" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerReceivableCreditLossExpenseReversal_01a0ef0c-093d-7ec3-b642-030021c74c53" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerReceivableCreditLossExpenseReversal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-86c7-7a36-8115-2663fdeac4bb" xlink:to="loc_us-gaap_ContractWithCustomerReceivableCreditLossExpenseReversal_01a0ef0c-093d-7ec3-b642-030021c74c53" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/SummaryOfMajorAccountingPoliciesDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#SummaryOfMajorAccountingPoliciesDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/SummaryOfMajorAccountingPoliciesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-7d64-919f-4a843b5b7698" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019fa40d-86c7-7998-87b8-fa2ec960e309" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-7d64-919f-4a843b5b7698" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019fa40d-86c7-7998-87b8-fa2ec960e309" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019fa40d-86c7-7008-ab65-30206df1b0fe" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019fa40d-86c7-7998-87b8-fa2ec960e309" xlink:to="loc_srt_RangeAxis_019fa40d-86c7-7008-ab65-30206df1b0fe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa40d-86c7-7008-ab65-30206df1b0fe_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019fa40d-86c7-7008-ab65-30206df1b0fe" xlink:to="loc_srt_RangeMember_019fa40d-86c7-7008-ab65-30206df1b0fe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa40d-86c7-73b5-aecf-3a3d9a10ed95" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019fa40d-86c7-7008-ab65-30206df1b0fe" xlink:to="loc_srt_RangeMember_019fa40d-86c7-73b5-aecf-3a3d9a10ed95" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019fa40d-86c7-70e2-8177-87a9d0021ad6" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019fa40d-86c7-7008-ab65-30206df1b0fe" xlink:to="loc_srt_MinimumMember_019fa40d-86c7-70e2-8177-87a9d0021ad6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019fa40d-86c7-7cdd-9de4-615803e91499" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019fa40d-86c7-7008-ab65-30206df1b0fe" xlink:to="loc_srt_MaximumMember_019fa40d-86c7-7cdd-9de4-615803e91499" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-70d1-98bc-7bbb33d06a64" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019fa40d-86c7-7998-87b8-fa2ec960e309" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-70d1-98bc-7bbb33d06a64" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-86c7-70d1-98bc-7bbb33d06a64_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-70d1-98bc-7bbb33d06a64" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-86c7-70d1-98bc-7bbb33d06a64_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-86c7-75d1-b08e-e14ad8d5e4c2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-70d1-98bc-7bbb33d06a64" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-86c7-75d1-b08e-e14ad8d5e4c2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_ManufacturedProductsMemberMember_019fa40d-86c7-7751-910c-fece3153ffbb" xlink:href="oii-20260930.xsd#oii_ManufacturedProductsMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-86c7-75d1-b08e-e14ad8d5e4c2" xlink:to="loc_oii_ManufacturedProductsMemberMember_019fa40d-86c7-7751-910c-fece3153ffbb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_OffshoreProjectsGroupMember_01a0ef0c-a67e-7b8c-8375-e2eaf6452610" xlink:href="oii-20260930.xsd#oii_OffshoreProjectsGroupMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-86c7-75d1-b08e-e14ad8d5e4c2" xlink:to="loc_oii_OffshoreProjectsGroupMember_01a0ef0c-a67e-7b8c-8375-e2eaf6452610" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019fa40d-86c7-772d-9337-d8f2ba263252" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019fa40d-86c7-7998-87b8-fa2ec960e309" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019fa40d-86c7-772d-9337-d8f2ba263252" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019fa40d-86c7-772d-9337-d8f2ba263252_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019fa40d-86c7-772d-9337-d8f2ba263252" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019fa40d-86c7-772d-9337-d8f2ba263252_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019fa40d-86c7-73cc-a75c-8a7b8b4f54e4" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019fa40d-86c7-772d-9337-d8f2ba263252" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019fa40d-86c7-73cc-a75c-8a7b8b4f54e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MarineServicesEquipmentMember_019fa40d-86c7-7bfa-9e05-551f448f1f40" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MarineServicesEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019fa40d-86c7-73cc-a75c-8a7b8b4f54e4" xlink:to="loc_us-gaap_MarineServicesEquipmentMember_019fa40d-86c7-7bfa-9e05-551f448f1f40" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_ROVMember_019fa40d-86c7-789c-ad6d-ade47d4dc43b" xlink:href="oii-20260930.xsd#oii_ROVMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019fa40d-86c7-73cc-a75c-8a7b8b4f54e4" xlink:to="loc_oii_ROVMember_019fa40d-86c7-789c-ad6d-ade47d4dc43b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_019fa40d-86c7-784f-8b4b-02f86d1ffe3a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019fa40d-86c7-73cc-a75c-8a7b8b4f54e4" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_019fa40d-86c7-784f-8b4b-02f86d1ffe3a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryWriteDown_019fa40d-86c7-7eb1-a2d1-5640217b9043" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryWriteDown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-7d64-919f-4a843b5b7698" xlink:to="loc_us-gaap_InventoryWriteDown_019fa40d-86c7-7eb1-a2d1-5640217b9043" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_019fa40d-86c7-7287-bac7-9fc56fbe8702" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInInventories"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-7d64-919f-4a843b5b7698" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_019fa40d-86c7-7287-bac7-9fc56fbe8702" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryValuationReserves_019fa40d-86c7-75a4-b23e-755365bc592b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryValuationReserves"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-7d64-919f-4a843b5b7698" xlink:to="loc_us-gaap_InventoryValuationReserves_019fa40d-86c7-75a4-b23e-755365bc592b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_019fa40d-86c7-71c4-8f74-dda13441aa04" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-7d64-919f-4a843b5b7698" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_019fa40d-86c7-71c4-8f74-dda13441aa04" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressGross_019fa40d-86c7-721c-bfdf-cec1ddd980f6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConstructionInProgressGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-7d64-919f-4a843b5b7698" xlink:to="loc_us-gaap_ConstructionInProgressGross_019fa40d-86c7-721c-bfdf-cec1ddd980f6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock_019fa40d-86c7-78f0-b94c-46fdfdd901b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fa40d-86c7-7d64-919f-4a843b5b7698" xlink:to="loc_us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock_019fa40d-86c7-78f0-b94c-46fdfdd901b2" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/RevenueDisaggregationofRevenueDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#RevenueDisaggregationofRevenueDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/RevenueDisaggregationofRevenueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-86c7-7f81-96ee-3e63cc898d48" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019fa40d-86c7-7e5e-bff1-1889ca4ea8af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-86c7-7f81-96ee-3e63cc898d48" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019fa40d-86c7-7e5e-bff1-1889ca4ea8af" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-7542-a5ed-f3cb8bf815e8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019fa40d-86c7-7e5e-bff1-1889ca4ea8af" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-7542-a5ed-f3cb8bf815e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-86c7-7542-a5ed-f3cb8bf815e8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-7542-a5ed-f3cb8bf815e8" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-86c7-7542-a5ed-f3cb8bf815e8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-86c7-75f9-8f69-e42b4de42ea9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-7542-a5ed-f3cb8bf815e8" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-86c7-75f9-8f69-e42b4de42ea9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_RovsMember_019fa40d-86c7-74af-891e-2ed0d2bc5747" xlink:href="oii-20260930.xsd#oii_RovsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-86c7-75f9-8f69-e42b4de42ea9" xlink:to="loc_oii_RovsMember_019fa40d-86c7-74af-891e-2ed0d2bc5747" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SubseaProductsMember_019fa40d-86c7-7219-ae21-2e28322822aa" xlink:href="oii-20260930.xsd#oii_SubseaProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-86c7-75f9-8f69-e42b4de42ea9" xlink:to="loc_oii_SubseaProductsMember_019fa40d-86c7-7219-ae21-2e28322822aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SubseaProjectsMember_019fa40d-86c7-734b-afa4-9b59574daee4" xlink:href="oii-20260930.xsd#oii_SubseaProjectsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-86c7-75f9-8f69-e42b4de42ea9" xlink:to="loc_oii_SubseaProjectsMember_019fa40d-86c7-734b-afa4-9b59574daee4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_AssetIntegrityMember_019fa40d-86c7-7112-a52c-76f59dca60c0" xlink:href="oii-20260930.xsd#oii_AssetIntegrityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-86c7-75f9-8f69-e42b4de42ea9" xlink:to="loc_oii_AssetIntegrityMember_019fa40d-86c7-7112-a52c-76f59dca60c0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_AdvancedTechnologiesMember_019fa40d-86c7-72ff-bb65-fd124215bace" xlink:href="oii-20260930.xsd#oii_AdvancedTechnologiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-86c7-75f9-8f69-e42b4de42ea9" xlink:to="loc_oii_AdvancedTechnologiesMember_019fa40d-86c7-72ff-bb65-fd124215bace" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_019fa40d-86c7-7ff4-a1ff-ec9d6061de57" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019fa40d-86c7-7e5e-bff1-1889ca4ea8af" xlink:to="loc_srt_StatementGeographicalAxis_019fa40d-86c7-7ff4-a1ff-ec9d6061de57" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-7ff4-a1ff-ec9d6061de57_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_019fa40d-86c7-7ff4-a1ff-ec9d6061de57" xlink:to="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-7ff4-a1ff-ec9d6061de57_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-716c-87bd-a268b031a71d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_019fa40d-86c7-7ff4-a1ff-ec9d6061de57" xlink:to="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-716c-87bd-a268b031a71d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_BR_019fa40d-86c7-7470-8847-958132344d64" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_BR"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-716c-87bd-a268b031a71d" xlink:to="loc_country_BR_019fa40d-86c7-7470-8847-958132344d64" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonUsMember_019fa40d-86c7-786b-9e8d-bd6a9fa1f9ef" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-716c-87bd-a268b031a71d" xlink:to="loc_us-gaap_NonUsMember_019fa40d-86c7-786b-9e8d-bd6a9fa1f9ef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019fa40d-86c7-7d85-9bef-1055a22cddcf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-86c7-7f81-96ee-3e63cc898d48" xlink:to="loc_us-gaap_Revenues_019fa40d-86c7-7d85-9bef-1055a22cddcf" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/RevenueRevenuebyGeographicAreaDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#RevenueRevenuebyGeographicAreaDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/RevenueRevenuebyGeographicAreaDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_oii_RevenuebyGeographicAreaLineItems_019fa40d-86c7-7d19-b391-6c893fb361df" xlink:href="oii-20260930.xsd#oii_RevenuebyGeographicAreaLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_RevenuebyGeographicAreaTable_019fa40d-86c7-71da-88e1-f5caed7a8465" xlink:href="oii-20260930.xsd#oii_RevenuebyGeographicAreaTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_oii_RevenuebyGeographicAreaLineItems_019fa40d-86c7-7d19-b391-6c893fb361df" xlink:to="loc_oii_RevenuebyGeographicAreaTable_019fa40d-86c7-71da-88e1-f5caed7a8465" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_019fa40d-86c7-7b19-8bbe-ee68d844c35b" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_oii_RevenuebyGeographicAreaTable_019fa40d-86c7-71da-88e1-f5caed7a8465" xlink:to="loc_srt_StatementGeographicalAxis_019fa40d-86c7-7b19-8bbe-ee68d844c35b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-7b19-8bbe-ee68d844c35b_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_019fa40d-86c7-7b19-8bbe-ee68d844c35b" xlink:to="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-7b19-8bbe-ee68d844c35b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-79fd-82b3-57b307b5aec9" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_019fa40d-86c7-7b19-8bbe-ee68d844c35b" xlink:to="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-79fd-82b3-57b307b5aec9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AfricaMember_019fa40d-86c7-7738-b838-c932c147464b" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_AfricaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-79fd-82b3-57b307b5aec9" xlink:to="loc_srt_AfricaMember_019fa40d-86c7-7738-b838-c932c147464b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_GB_019fa40d-86c7-70b9-8054-9f02c92a676e" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_GB"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-79fd-82b3-57b307b5aec9" xlink:to="loc_country_GB_019fa40d-86c7-70b9-8054-9f02c92a676e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_NO_019fa40d-86c7-765c-b7fe-b95c71f8d92b" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_NO"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-79fd-82b3-57b307b5aec9" xlink:to="loc_country_NO_019fa40d-86c7-765c-b7fe-b95c71f8d92b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaPacificMember_019fa40d-86c7-7b77-b451-e35ab8bd8581" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_AsiaPacificMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-79fd-82b3-57b307b5aec9" xlink:to="loc_srt_AsiaPacificMember_019fa40d-86c7-7b77-b451-e35ab8bd8581" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_BR_019fa40d-86c7-7ddb-b12e-8e83e61460d3" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_BR"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-79fd-82b3-57b307b5aec9" xlink:to="loc_country_BR_019fa40d-86c7-7ddb-b12e-8e83e61460d3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_OtherGeographicalMember_019fa40d-86c7-7397-af84-dcb4fcceb1ce" xlink:href="oii-20260930.xsd#oii_OtherGeographicalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-79fd-82b3-57b307b5aec9" xlink:to="loc_oii_OtherGeographicalMember_019fa40d-86c7-7397-af84-dcb4fcceb1ce" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonUsMember_019fa40d-86c7-73d8-ac70-e642a81a7f36" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-79fd-82b3-57b307b5aec9" xlink:to="loc_us-gaap_NonUsMember_019fa40d-86c7-73d8-ac70-e642a81a7f36" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_019fa40d-86c7-76e1-8647-2ad5023c7fe5" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-79fd-82b3-57b307b5aec9" xlink:to="loc_country_US_019fa40d-86c7-76e1-8647-2ad5023c7fe5" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019fa40d-86c7-766b-af85-225ac532f21d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oii_RevenuebyGeographicAreaLineItems_019fa40d-86c7-7d19-b391-6c893fb361df" xlink:to="loc_us-gaap_Revenues_019fa40d-86c7-766b-af85-225ac532f21d" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/RevenueRevenuebyTimingofTransferofGoodsorServicesDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#RevenueRevenuebyTimingofTransferofGoodsorServicesDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/RevenueRevenuebyTimingofTransferofGoodsorServicesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredRevenueArrangementLineItems_019fa40d-86c7-7db3-b476-e8e5dc7a9de1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredRevenueArrangementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredRevenueArrangementByTypeTable_019fa40d-86c7-7fc8-ada9-4b690d27cba5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredRevenueArrangementByTypeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DeferredRevenueArrangementLineItems_019fa40d-86c7-7db3-b476-e8e5dc7a9de1" xlink:to="loc_us-gaap_DeferredRevenueArrangementByTypeTable_019fa40d-86c7-7fc8-ada9-4b690d27cba5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_019fa40d-86c7-7c90-82c7-97d82f3c64dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TimingOfTransferOfGoodOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DeferredRevenueArrangementByTypeTable_019fa40d-86c7-7fc8-ada9-4b690d27cba5" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_019fa40d-86c7-7c90-82c7-97d82f3c64dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_019fa40d-86c7-7c90-82c7-97d82f3c64dc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_019fa40d-86c7-7c90-82c7-97d82f3c64dc" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_019fa40d-86c7-7c90-82c7-97d82f3c64dc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_019fa40d-86c7-7db3-bd70-769dc88ef74d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_019fa40d-86c7-7c90-82c7-97d82f3c64dc" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_019fa40d-86c7-7db3-bd70-769dc88ef74d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferredAtPointInTimeMember_019fa40d-86c7-7576-9f06-87e2bd64e561" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransferredAtPointInTimeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_019fa40d-86c7-7db3-bd70-769dc88ef74d" xlink:to="loc_us-gaap_TransferredAtPointInTimeMember_019fa40d-86c7-7576-9f06-87e2bd64e561" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferredOverTimeMember_019fa40d-86c7-7bc0-95c3-3ad57f9286ff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransferredOverTimeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_019fa40d-86c7-7db3-bd70-769dc88ef74d" xlink:to="loc_us-gaap_TransferredOverTimeMember_019fa40d-86c7-7bc0-95c3-3ad57f9286ff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-7a33-91fd-d8393387317d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DeferredRevenueArrangementByTypeTable_019fa40d-86c7-7fc8-ada9-4b690d27cba5" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-7a33-91fd-d8393387317d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-86c7-7a33-91fd-d8393387317d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-7a33-91fd-d8393387317d" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-86c7-7a33-91fd-d8393387317d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-86c7-749c-b4bc-d45daa079d66" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-86c7-7a33-91fd-d8393387317d" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-86c7-749c-b4bc-d45daa079d66" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_EnergyServicesAndProductsMemberMember_019fa40d-86c7-76a4-84a8-d29da62ad9cd" xlink:href="oii-20260930.xsd#oii_EnergyServicesAndProductsMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-86c7-749c-b4bc-d45daa079d66" xlink:to="loc_oii_EnergyServicesAndProductsMemberMember_019fa40d-86c7-76a4-84a8-d29da62ad9cd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementScenarioAxis_019fa40d-86c7-7f98-83ea-0d0c0ee80191" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementScenarioAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DeferredRevenueArrangementByTypeTable_019fa40d-86c7-7fc8-ada9-4b690d27cba5" xlink:to="loc_srt_StatementScenarioAxis_019fa40d-86c7-7f98-83ea-0d0c0ee80191" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_019fa40d-86c7-7f98-83ea-0d0c0ee80191_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_019fa40d-86c7-7f98-83ea-0d0c0ee80191" xlink:to="loc_srt_ScenarioUnspecifiedDomain_019fa40d-86c7-7f98-83ea-0d0c0ee80191_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_019fa40d-86c7-78da-901a-e5b09772fbe1" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_019fa40d-86c7-7f98-83ea-0d0c0ee80191" xlink:to="loc_srt_ScenarioUnspecifiedDomain_019fa40d-86c7-78da-901a-e5b09772fbe1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioForecastMember_019fa40d-86c7-78c7-9b7c-0a47d3c4bd6b" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScenarioForecastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_019fa40d-86c7-78da-901a-e5b09772fbe1" xlink:to="loc_srt_ScenarioForecastMember_019fa40d-86c7-78c7-9b7c-0a47d3c4bd6b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019fa40d-86c7-7e2a-be1f-a3bffcfd3f69" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DeferredRevenueArrangementByTypeTable_019fa40d-86c7-7fc8-ada9-4b690d27cba5" xlink:to="loc_srt_ConsolidationItemsAxis_019fa40d-86c7-7e2a-be1f-a3bffcfd3f69" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019fa40d-86c7-7e2a-be1f-a3bffcfd3f69_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019fa40d-86c7-7e2a-be1f-a3bffcfd3f69" xlink:to="loc_srt_ConsolidationItemsDomain_019fa40d-86c7-7e2a-be1f-a3bffcfd3f69_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019fa40d-86c7-7637-8891-4529e9cdcaa4" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019fa40d-86c7-7e2a-be1f-a3bffcfd3f69" xlink:to="loc_srt_ConsolidationItemsDomain_019fa40d-86c7-7637-8891-4529e9cdcaa4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_019fa40d-86c7-7628-bbf1-c6d23623abaa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019fa40d-86c7-7637-8891-4529e9cdcaa4" xlink:to="loc_us-gaap_OperatingSegmentsMember_019fa40d-86c7-7628-bbf1-c6d23623abaa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_019fa40d-86c7-7399-a076-322d7ab5ae91" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DeferredRevenueArrangementByTypeTable_019fa40d-86c7-7fc8-ada9-4b690d27cba5" xlink:to="loc_srt_StatementGeographicalAxis_019fa40d-86c7-7399-a076-322d7ab5ae91" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-7399-a076-322d7ab5ae91_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_019fa40d-86c7-7399-a076-322d7ab5ae91" xlink:to="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-7399-a076-322d7ab5ae91_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-7976-a5c0-42a1269512d1" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_019fa40d-86c7-7399-a076-322d7ab5ae91" xlink:to="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-7976-a5c0-42a1269512d1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonUsMember_019fa40d-86c7-7cf2-b720-b4692b7d0e5f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-7976-a5c0-42a1269512d1" xlink:to="loc_us-gaap_NonUsMember_019fa40d-86c7-7cf2-b720-b4692b7d0e5f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AfricaMember_019fa40d-86c7-74fe-9788-9d93453fa8d5" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_AfricaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-7976-a5c0-42a1269512d1" xlink:to="loc_srt_AfricaMember_019fa40d-86c7-74fe-9788-9d93453fa8d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_GB_019fa40d-86c7-7c20-aaa9-9207089f205d" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_GB"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-7976-a5c0-42a1269512d1" xlink:to="loc_country_GB_019fa40d-86c7-7c20-aaa9-9207089f205d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_NO_019fa40d-86c7-7e3f-a9b8-a09fd7e09a55" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_NO"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-7976-a5c0-42a1269512d1" xlink:to="loc_country_NO_019fa40d-86c7-7e3f-a9b8-a09fd7e09a55" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_BR_019fa40d-86c7-7a6f-bb55-b2f3d9e91f90" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_BR"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-7976-a5c0-42a1269512d1" xlink:to="loc_country_BR_019fa40d-86c7-7a6f-bb55-b2f3d9e91f90" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaPacificMember_019fa40d-86c7-7087-b404-488321021e11" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_AsiaPacificMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-7976-a5c0-42a1269512d1" xlink:to="loc_srt_AsiaPacificMember_019fa40d-86c7-7087-b404-488321021e11" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_OtherGeographicalMember_019fa40d-86c7-7236-a037-26c0b8cbf127" xlink:href="oii-20260930.xsd#oii_OtherGeographicalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-7976-a5c0-42a1269512d1" xlink:to="loc_oii_OtherGeographicalMember_019fa40d-86c7-7236-a037-26c0b8cbf127" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_019fa40d-86c7-7bfb-b8c5-8d237ac306c8" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-86c7-7976-a5c0-42a1269512d1" xlink:to="loc_country_US_019fa40d-86c7-7bfb-b8c5-8d237ac306c8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019fa40d-86c7-7cc0-a4f6-e8732e174637" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredRevenueArrangementLineItems_019fa40d-86c7-7db3-b476-e8e5dc7a9de1" xlink:to="loc_us-gaap_Revenues_019fa40d-86c7-7cc0-a4f6-e8732e174637" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_019fa40d-86c7-7ba4-9d40-e565d91f64a4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredRevenueArrangementLineItems_019fa40d-86c7-7db3-b476-e8e5dc7a9de1" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_019fa40d-86c7-7ba4-9d40-e565d91f64a4" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/SelectedBalanceSheetInformationDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#SelectedBalanceSheetInformationDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/SelectedBalanceSheetInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryLineItems_019fa40d-878f-78bc-949b-11e79e425978" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryCurrentTable_019fa40d-878f-796b-a2a2-4cd3c78d384b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryCurrentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_InventoryLineItems_019fa40d-878f-78bc-949b-11e79e425978" xlink:to="loc_us-gaap_InventoryCurrentTable_019fa40d-878f-796b-a2a2-4cd3c78d384b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-878f-729d-915a-dd9e507c7182" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_InventoryCurrentTable_019fa40d-878f-796b-a2a2-4cd3c78d384b" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-878f-729d-915a-dd9e507c7182" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-878f-729d-915a-dd9e507c7182_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-878f-729d-915a-dd9e507c7182" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-878f-729d-915a-dd9e507c7182_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-878f-7e16-9e73-ed92eaf97f5e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-878f-729d-915a-dd9e507c7182" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-878f-7e16-9e73-ed92eaf97f5e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SubseaRoboticsMemberMember_019fa40d-878f-7cb5-9588-60f7e57d25e8" xlink:href="oii-20260930.xsd#oii_SubseaRoboticsMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-7e16-9e73-ed92eaf97f5e" xlink:to="loc_oii_SubseaRoboticsMemberMember_019fa40d-878f-7cb5-9588-60f7e57d25e8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_ManufacturedProductsMemberMember_019fa40d-878f-789c-ad0a-74a74b60c302" xlink:href="oii-20260930.xsd#oii_ManufacturedProductsMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-7e16-9e73-ed92eaf97f5e" xlink:to="loc_oii_ManufacturedProductsMemberMember_019fa40d-878f-789c-ad0a-74a74b60c302" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_019fa40d-878f-71a3-9fe3-e19548effba8" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_InventoryCurrentTable_019fa40d-878f-796b-a2a2-4cd3c78d384b" xlink:to="loc_srt_StatementGeographicalAxis_019fa40d-878f-71a3-9fe3-e19548effba8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019fa40d-878f-71a3-9fe3-e19548effba8_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_019fa40d-878f-71a3-9fe3-e19548effba8" xlink:to="loc_srt_SegmentGeographicalDomain_019fa40d-878f-71a3-9fe3-e19548effba8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019fa40d-878f-7fc8-b21f-8133a4e21884" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_019fa40d-878f-71a3-9fe3-e19548effba8" xlink:to="loc_srt_SegmentGeographicalDomain_019fa40d-878f-7fc8-b21f-8133a4e21884" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerSegmentBenchmarkMember_019fa40d-878f-7422-957c-a292493643ba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerSegmentBenchmarkMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-878f-7fc8-b21f-8133a4e21884" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerSegmentBenchmarkMember_019fa40d-878f-7422-957c-a292493643ba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_AO_019fa40d-878f-7cc8-9f15-da8a90442d29" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_AO"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-878f-7fc8-b21f-8133a4e21884" xlink:to="loc_country_AO_019fa40d-878f-7cc8-9f15-da8a90442d29" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_019fa40d-878f-7a91-ba88-493cd21a8795" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryLineItems_019fa40d-878f-78bc-949b-11e79e425978" xlink:to="loc_us-gaap_InventoryNet_019fa40d-878f-7a91-ba88-493cd21a8795" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseCurrent_019fa40d-878f-7583-b60c-3c603b2ec3ee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrepaidExpenseCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryLineItems_019fa40d-878f-78bc-949b-11e79e425978" xlink:to="loc_us-gaap_PrepaidExpenseCurrent_019fa40d-878f-7583-b60c-3c603b2ec3ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCash_01a0eebd-0505-70d2-988e-1647ae56ea5c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryLineItems_019fa40d-878f-78bc-949b-11e79e425978" xlink:to="loc_us-gaap_RestrictedCash_01a0eebd-0505-70d2-988e-1647ae56ea5c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestments_019fa40d-878f-7d0e-b458-08b49dff6257" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryLineItems_019fa40d-878f-78bc-949b-11e79e425978" xlink:to="loc_us-gaap_ShortTermInvestments_019fa40d-878f-7d0e-b458-08b49dff6257" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsCurrent_019fa40d-878f-771d-ba4c-39ea221f6dc3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryLineItems_019fa40d-878f-78bc-949b-11e79e425978" xlink:to="loc_us-gaap_OtherAssetsCurrent_019fa40d-878f-771d-ba4c-39ea221f6dc3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryGross_019fa40d-878f-7383-8623-209f659d0816" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryLineItems_019fa40d-878f-78bc-949b-11e79e425978" xlink:to="loc_us-gaap_InventoryGross_019fa40d-878f-7383-8623-209f659d0816" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryPartsAndComponentsNetOfReserves_019fa40d-878f-71c3-9a76-40cd32eddf8c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryPartsAndComponentsNetOfReserves"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryLineItems_019fa40d-878f-78bc-949b-11e79e425978" xlink:to="loc_us-gaap_InventoryPartsAndComponentsNetOfReserves_019fa40d-878f-71c3-9a76-40cd32eddf8c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherInventoryNetOfReserves_019fa40d-878f-7558-b5f2-b9f9119df877" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherInventoryNetOfReserves"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryLineItems_019fa40d-878f-78bc-949b-11e79e425978" xlink:to="loc_us-gaap_OtherInventoryNetOfReserves_019fa40d-878f-7558-b5f2-b9f9119df877" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/DebtScheduleofLongTermDebtDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#DebtScheduleofLongTermDebtDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/DebtScheduleofLongTermDebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019fa40d-878f-7dc5-9936-7c471d34a582" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019fa40d-878f-76e0-b5f0-9657ad3d9c02" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fa40d-878f-7dc5-9936-7c471d34a582" xlink:to="loc_us-gaap_DebtInstrumentTable_019fa40d-878f-76e0-b5f0-9657ad3d9c02" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_01a0400a-5a94-73c5-b7a8-f760911d7c78" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019fa40d-878f-76e0-b5f0-9657ad3d9c02" xlink:to="loc_us-gaap_DebtInstrumentAxis_01a0400a-5a94-73c5-b7a8-f760911d7c78" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a0400a-5a94-73c5-b7a8-f760911d7c78_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a0400a-5a94-73c5-b7a8-f760911d7c78" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a0400a-5a94-73c5-b7a8-f760911d7c78_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a0400a-5a94-7462-91ec-1ac047233be6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a0400a-5a94-73c5-b7a8-f760911d7c78" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a0400a-5a94-7462-91ec-1ac047233be6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SeniorNotesdue2028Member_01a0400a-5a94-749d-b1f6-9f9a8dba0bab" xlink:href="oii-20260930.xsd#oii_SeniorNotesdue2028Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a0400a-5a94-7462-91ec-1ac047233be6" xlink:to="loc_oii_SeniorNotesdue2028Member_01a0400a-5a94-749d-b1f6-9f9a8dba0bab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SeniorNotesDue2034Member_01a0400a-d389-700c-b947-75d55e74cdc5" xlink:href="oii-20260930.xsd#oii_SeniorNotesDue2034Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a0400a-5a94-7462-91ec-1ac047233be6" xlink:to="loc_oii_SeniorNotesDue2034Member_01a0400a-d389-700c-b947-75d55e74cdc5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019fa40d-878f-7bb6-bf43-bd36b27b2195" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fa40d-878f-7dc5-9936-7c471d34a582" xlink:to="loc_dei_DocumentPeriodEndDate_019fa40d-878f-7bb6-bf43-bd36b27b2195" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotes_019fa40d-878f-7e9c-9fec-c960dcd9d8a6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorNotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fa40d-878f-7dc5-9936-7c471d34a582" xlink:to="loc_us-gaap_SeniorNotes_019fa40d-878f-7e9c-9fec-c960dcd9d8a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueHedgeAssetsAtFairValue_019fa40d-878f-7392-903f-914f618703d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueHedgeAssetsAtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fa40d-878f-7dc5-9936-7c471d34a582" xlink:to="loc_us-gaap_FairValueHedgeAssetsAtFairValue_019fa40d-878f-7392-903f-914f618703d8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueHedgeLiabilitiesAtFairValue_019fa40d-878f-70a1-acac-04fffca25de8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueHedgeLiabilitiesAtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fa40d-878f-7dc5-9936-7c471d34a582" xlink:to="loc_us-gaap_FairValueHedgeLiabilitiesAtFairValue_019fa40d-878f-70a1-acac-04fffca25de8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnOilAndGasHedgingActivity_019fa40d-878f-7675-a443-44529e48ea99" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnOilAndGasHedgingActivity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fa40d-878f-7dc5-9936-7c471d34a582" xlink:to="loc_us-gaap_GainLossOnOilAndGasHedgingActivity_019fa40d-878f-7675-a443-44529e48ea99" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredGainLossOnDiscontinuationOfFairValueHedge_019fa40d-878f-72ef-8a14-7f34811af503" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredGainLossOnDiscontinuationOfFairValueHedge"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fa40d-878f-7dc5-9936-7c471d34a582" xlink:to="loc_us-gaap_DeferredGainLossOnDiscontinuationOfFairValueHedge_019fa40d-878f-72ef-8a14-7f34811af503" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnamortizedDebtIssuanceExpense_019fa40d-878f-7c3b-8a5c-71e4301e9c24" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UnamortizedDebtIssuanceExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fa40d-878f-7dc5-9936-7c471d34a582" xlink:to="loc_us-gaap_UnamortizedDebtIssuanceExpense_019fa40d-878f-7c3b-8a5c-71e4301e9c24" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_019fa40d-878f-7b0b-9dc3-34944d2d83df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fa40d-878f-7dc5-9936-7c471d34a582" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_019fa40d-878f-7b0b-9dc3-34944d2d83df" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/DebtAdditionalInformationDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#DebtAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/DebtAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_019fa40d-878f-7f90-8834-c534e85d0526" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_019fa40d-878f-7f90-8834-c534e85d0526" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_019fa40d-878f-7a04-bf00-12596535aa71" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentRedemptionPeriodAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019fa40d-878f-7f90-8834-c534e85d0526" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_019fa40d-878f-7a04-bf00-12596535aa71" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_019fa40d-878f-7a04-bf00-12596535aa71_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_019fa40d-878f-7a04-bf00-12596535aa71" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_019fa40d-878f-7a04-bf00-12596535aa71_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_019fa40d-878f-75c4-8508-cfc1f765d084" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_019fa40d-878f-7a04-bf00-12596535aa71" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_019fa40d-878f-75c4-8508-cfc1f765d084" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodOneMember_019fa40d-878f-7526-b33c-ae027cb8b54e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentRedemptionPeriodOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_019fa40d-878f-75c4-8508-cfc1f765d084" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodOneMember_019fa40d-878f-7526-b33c-ae027cb8b54e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodTwoMember_019fa40d-878f-7c16-a04c-0dccf4084754" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentRedemptionPeriodTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_019fa40d-878f-75c4-8508-cfc1f765d084" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodTwoMember_019fa40d-878f-7c16-a04c-0dccf4084754" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_InterestRateComponentAxis_019fa40d-878f-7000-a416-01495430fb0e" xlink:href="oii-20260930.xsd#oii_InterestRateComponentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019fa40d-878f-7f90-8834-c534e85d0526" xlink:to="loc_oii_InterestRateComponentAxis_019fa40d-878f-7000-a416-01495430fb0e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_InterestRateComponentDomain_019fa40d-878f-7000-a416-01495430fb0e_default" xlink:href="oii-20260930.xsd#oii_InterestRateComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_oii_InterestRateComponentAxis_019fa40d-878f-7000-a416-01495430fb0e" xlink:to="loc_oii_InterestRateComponentDomain_019fa40d-878f-7000-a416-01495430fb0e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_InterestRateComponentDomain_019fa40d-878f-7e3c-b2ff-d1746e062b58" xlink:href="oii-20260930.xsd#oii_InterestRateComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_oii_InterestRateComponentAxis_019fa40d-878f-7000-a416-01495430fb0e" xlink:to="loc_oii_InterestRateComponentDomain_019fa40d-878f-7e3c-b2ff-d1746e062b58" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_ApplicableMarginMember_019fa40d-878f-731e-bddf-a2e655c464be" xlink:href="oii-20260930.xsd#oii_ApplicableMarginMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oii_InterestRateComponentDomain_019fa40d-878f-7e3c-b2ff-d1746e062b58" xlink:to="loc_oii_ApplicableMarginMember_019fa40d-878f-731e-bddf-a2e655c464be" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_AdjustedBaseRateMember_019fa40d-878f-7b8b-b27e-6201b371bbe4" xlink:href="oii-20260930.xsd#oii_AdjustedBaseRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oii_InterestRateComponentDomain_019fa40d-878f-7e3c-b2ff-d1746e062b58" xlink:to="loc_oii_AdjustedBaseRateMember_019fa40d-878f-7b8b-b27e-6201b371bbe4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_AdvanceTypeAxis_019fa40d-878f-7cc9-b060-d35078670a3f" xlink:href="oii-20260930.xsd#oii_AdvanceTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019fa40d-878f-7f90-8834-c534e85d0526" xlink:to="loc_oii_AdvanceTypeAxis_019fa40d-878f-7cc9-b060-d35078670a3f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_AdvanceTypeDomain_019fa40d-878f-7cc9-b060-d35078670a3f_default" xlink:href="oii-20260930.xsd#oii_AdvanceTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_oii_AdvanceTypeAxis_019fa40d-878f-7cc9-b060-d35078670a3f" xlink:to="loc_oii_AdvanceTypeDomain_019fa40d-878f-7cc9-b060-d35078670a3f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_AdvanceTypeDomain_019fa40d-878f-74f6-bbc4-60a072abe70f" xlink:href="oii-20260930.xsd#oii_AdvanceTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_oii_AdvanceTypeAxis_019fa40d-878f-7cc9-b060-d35078670a3f" xlink:to="loc_oii_AdvanceTypeDomain_019fa40d-878f-74f6-bbc4-60a072abe70f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_AdjustedBaseRateAdvancesMember_019fa40d-878f-7639-a7fe-37892a081342" xlink:href="oii-20260930.xsd#oii_AdjustedBaseRateAdvancesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oii_AdvanceTypeDomain_019fa40d-878f-74f6-bbc4-60a072abe70f" xlink:to="loc_oii_AdjustedBaseRateAdvancesMember_019fa40d-878f-7639-a7fe-37892a081342" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_EurodollarAdvancesMember_019fa40d-878f-7968-867c-2203c85ebada" xlink:href="oii-20260930.xsd#oii_EurodollarAdvancesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oii_AdvanceTypeDomain_019fa40d-878f-74f6-bbc4-60a072abe70f" xlink:to="loc_oii_EurodollarAdvancesMember_019fa40d-878f-7968-867c-2203c85ebada" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_BaseRateTypeAxis_019fa40d-878f-7ee2-baab-1a96c66d6220" xlink:href="oii-20260930.xsd#oii_BaseRateTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019fa40d-878f-7f90-8834-c534e85d0526" xlink:to="loc_oii_BaseRateTypeAxis_019fa40d-878f-7ee2-baab-1a96c66d6220" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_BaseRateTypeDomain_019fa40d-878f-7ee2-baab-1a96c66d6220_default" xlink:href="oii-20260930.xsd#oii_BaseRateTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_oii_BaseRateTypeAxis_019fa40d-878f-7ee2-baab-1a96c66d6220" xlink:to="loc_oii_BaseRateTypeDomain_019fa40d-878f-7ee2-baab-1a96c66d6220_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_BaseRateTypeDomain_019fa40d-878f-7500-8bec-253c7b43a4fb" xlink:href="oii-20260930.xsd#oii_BaseRateTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_oii_BaseRateTypeAxis_019fa40d-878f-7ee2-baab-1a96c66d6220" xlink:to="loc_oii_BaseRateTypeDomain_019fa40d-878f-7500-8bec-253c7b43a4fb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_FederalFundsRate_019fa40d-878f-7303-82dc-934f3d16b155" xlink:href="oii-20260930.xsd#oii_FederalFundsRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oii_BaseRateTypeDomain_019fa40d-878f-7500-8bec-253c7b43a4fb" xlink:to="loc_oii_FederalFundsRate_019fa40d-878f-7303-82dc-934f3d16b155" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_EurodollarRateMember_019fa40d-878f-7671-8aba-2c7cf52b0f44" xlink:href="oii-20260930.xsd#oii_EurodollarRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oii_BaseRateTypeDomain_019fa40d-878f-7500-8bec-253c7b43a4fb" xlink:to="loc_oii_EurodollarRateMember_019fa40d-878f-7671-8aba-2c7cf52b0f44" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019fa40d-878f-750d-a92e-c416bf6f81e1" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019fa40d-878f-7f90-8834-c534e85d0526" xlink:to="loc_srt_RangeAxis_019fa40d-878f-750d-a92e-c416bf6f81e1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa40d-878f-750d-a92e-c416bf6f81e1_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019fa40d-878f-750d-a92e-c416bf6f81e1" xlink:to="loc_srt_RangeMember_019fa40d-878f-750d-a92e-c416bf6f81e1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa40d-878f-7248-8e9c-eb0f21920dac" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019fa40d-878f-750d-a92e-c416bf6f81e1" xlink:to="loc_srt_RangeMember_019fa40d-878f-7248-8e9c-eb0f21920dac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019fa40d-878f-7bfe-a06a-7c3d5223865d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fa40d-878f-7248-8e9c-eb0f21920dac" xlink:to="loc_srt_MinimumMember_019fa40d-878f-7bfe-a06a-7c3d5223865d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019fa40d-878f-7e07-bc9b-52e5b023af13" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fa40d-878f-7248-8e9c-eb0f21920dac" xlink:to="loc_srt_MaximumMember_019fa40d-878f-7e07-bc9b-52e5b023af13" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019fa40d-878f-759c-962e-bc2750a0ce94" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019fa40d-878f-7f90-8834-c534e85d0526" xlink:to="loc_us-gaap_DebtInstrumentAxis_019fa40d-878f-759c-962e-bc2750a0ce94" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-759c-962e-bc2750a0ce94_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019fa40d-878f-759c-962e-bc2750a0ce94" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-759c-962e-bc2750a0ce94_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-749a-8d3f-3f918a3a7a89" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019fa40d-878f-759c-962e-bc2750a0ce94" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-749a-8d3f-3f918a3a7a89" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019fa40d-878f-7078-98b7-229b93456507" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-749a-8d3f-3f918a3a7a89" xlink:to="loc_us-gaap_LineOfCreditMember_019fa40d-878f-7078-98b7-229b93456507" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_CreditAgreementMember_019fa40d-878f-7f1f-98b2-40349a6b0768" xlink:href="oii-20260930.xsd#oii_CreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-749a-8d3f-3f918a3a7a89" xlink:to="loc_oii_CreditAgreementMember_019fa40d-878f-7f1f-98b2-40349a6b0768" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SeniorNotesdue2028Member_019fa40d-878f-7b0b-ae0e-d7ffab01f42e" xlink:href="oii-20260930.xsd#oii_SeniorNotesdue2028Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-749a-8d3f-3f918a3a7a89" xlink:to="loc_oii_SeniorNotesdue2028Member_019fa40d-878f-7b0b-ae0e-d7ffab01f42e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SeniorNotesdue2024Member_019fa40d-878f-70c2-8d2b-1666e979e669" xlink:href="oii-20260930.xsd#oii_SeniorNotesdue2024Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-749a-8d3f-3f918a3a7a89" xlink:to="loc_oii_SeniorNotesdue2024Member_019fa40d-878f-70c2-8d2b-1666e979e669" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_019fa40d-878f-7f7f-8e06-0b017d355d10" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-749a-8d3f-3f918a3a7a89" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_019fa40d-878f-7f7f-8e06-0b017d355d10" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_019fa40d-878f-7b89-92cf-90fb9f20c422" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-749a-8d3f-3f918a3a7a89" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_019fa40d-878f-7b89-92cf-90fb9f20c422" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_019fa40d-878f-7cd2-b6c8-ee08f580cf52" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-749a-8d3f-3f918a3a7a89" xlink:to="loc_us-gaap_SeniorNotesMember_019fa40d-878f-7cd2-b6c8-ee08f580cf52" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SeniorNotesDue2034Member_019fa40d-878f-7309-94cc-d284ed64f619" xlink:href="oii-20260930.xsd#oii_SeniorNotesDue2034Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-749a-8d3f-3f918a3a7a89" xlink:to="loc_oii_SeniorNotesDue2034Member_019fa40d-878f-7309-94cc-d284ed64f619" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_RevolvingCreditFacilityApr2022Member_01a0eec5-4c3f-7204-903c-93510061665f" xlink:href="oii-20260930.xsd#oii_RevolvingCreditFacilityApr2022Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-749a-8d3f-3f918a3a7a89" xlink:to="loc_oii_RevolvingCreditFacilityApr2022Member_01a0eec5-4c3f-7204-903c-93510061665f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SeniorNotesAndRCFMemberMember_01a15fef-7291-7a56-895e-bfd11b6eff69" xlink:href="oii-20260930.xsd#oii_SeniorNotesAndRCFMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-749a-8d3f-3f918a3a7a89" xlink:to="loc_oii_SeniorNotesAndRCFMemberMember_01a15fef-7291-7a56-895e-bfd11b6eff69" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019fa40d-878f-7c84-8860-a1fe5010913e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019fa40d-878f-7f90-8834-c534e85d0526" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019fa40d-878f-7c84-8860-a1fe5010913e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019fa40d-878f-7c84-8860-a1fe5010913e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019fa40d-878f-7c84-8860-a1fe5010913e" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019fa40d-878f-7c84-8860-a1fe5010913e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019fa40d-878f-7253-bcb1-26de595c10c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019fa40d-878f-7c84-8860-a1fe5010913e" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019fa40d-878f-7253-bcb1-26de595c10c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeMember_019fa40d-878f-7580-ba40-dbd46209dbbd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019fa40d-878f-7253-bcb1-26de595c10c7" xlink:to="loc_us-gaap_DerivativeMember_019fa40d-878f-7580-ba40-dbd46209dbbd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_019fa40d-878f-7b1b-b709-dae10c5b4da6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019fa40d-878f-7f90-8834-c534e85d0526" xlink:to="loc_us-gaap_CreditFacilityAxis_019fa40d-878f-7b1b-b709-dae10c5b4da6" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019fa40d-878f-7b1b-b709-dae10c5b4da6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_019fa40d-878f-7b1b-b709-dae10c5b4da6" xlink:to="loc_us-gaap_CreditFacilityDomain_019fa40d-878f-7b1b-b709-dae10c5b4da6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019fa40d-878f-72fa-abe5-e7c5be6d842f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_019fa40d-878f-7b1b-b709-dae10c5b4da6" xlink:to="loc_us-gaap_CreditFacilityDomain_019fa40d-878f-72fa-abe5-e7c5be6d842f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SublimitMemberMember_019fa40d-878f-7b85-96d9-6876c526aa18" xlink:href="oii-20260930.xsd#oii_SublimitMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019fa40d-878f-72fa-abe5-e7c5be6d842f" xlink:to="loc_oii_SublimitMemberMember_019fa40d-878f-7b85-96d9-6876c526aa18" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_LineOfCreditAmendmentNo.2July2026Member_019fa40d-878f-70e9-8014-3568391aa278" xlink:href="oii-20260930.xsd#oii_LineOfCreditAmendmentNo.2July2026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019fa40d-878f-72fa-abe5-e7c5be6d842f" xlink:to="loc_oii_LineOfCreditAmendmentNo.2July2026Member_019fa40d-878f-70e9-8014-3568391aa278" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_LineOfCreditAmendmentNo.1Sept2023Member_01a14fc8-cea0-736e-aa68-9a8a0741a823" xlink:href="oii-20260930.xsd#oii_LineOfCreditAmendmentNo.1Sept2023Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019fa40d-878f-72fa-abe5-e7c5be6d842f" xlink:to="loc_oii_LineOfCreditAmendmentNo.1Sept2023Member_01a14fc8-cea0-736e-aa68-9a8a0741a823" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementScenarioAxis_019fa40d-878f-79dc-9e5e-8b618e37edf2" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementScenarioAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019fa40d-878f-7f90-8834-c534e85d0526" xlink:to="loc_srt_StatementScenarioAxis_019fa40d-878f-79dc-9e5e-8b618e37edf2" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_019fa40d-878f-79dc-9e5e-8b618e37edf2_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_019fa40d-878f-79dc-9e5e-8b618e37edf2" xlink:to="loc_srt_ScenarioUnspecifiedDomain_019fa40d-878f-79dc-9e5e-8b618e37edf2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_019fa40d-878f-774a-8ea8-775857493a0c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_019fa40d-878f-79dc-9e5e-8b618e37edf2" xlink:to="loc_srt_ScenarioUnspecifiedDomain_019fa40d-878f-774a-8ea8-775857493a0c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioForecastMember_019fa40d-878f-7123-af99-56d01c6e03cd" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScenarioForecastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_019fa40d-878f-774a-8ea8-775857493a0c" xlink:to="loc_srt_ScenarioForecastMember_019fa40d-878f-7123-af99-56d01c6e03cd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_019fa40d-878f-7324-bbd0-da03d418e863" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019fa40d-878f-7f90-8834-c534e85d0526" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_019fa40d-878f-7324-bbd0-da03d418e863" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019fa40d-878f-7324-bbd0-da03d418e863_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019fa40d-878f-7324-bbd0-da03d418e863" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019fa40d-878f-7324-bbd0-da03d418e863_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019fa40d-878f-7b58-9073-05ec2d5ccf6f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019fa40d-878f-7324-bbd0-da03d418e863" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019fa40d-878f-7b58-9073-05ec2d5ccf6f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_019fa40d-878f-7cda-b305-2e8472187097" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_019fa40d-878f-7b58-9073-05ec2d5ccf6f" xlink:to="loc_us-gaap_SubsequentEventMember_019fa40d-878f-7cda-b305-2e8472187097" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotes_019fa40d-878f-756d-a23a-c9717a0609ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorNotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_SeniorNotes_019fa40d-878f-756d-a23a-c9717a0609ac" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019fa40d-878f-75ee-9f42-a4d0cb710f86" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019fa40d-878f-75ee-9f42-a4d0cb710f86" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019fa40d-878f-7f90-8e07-e6ba69849eef" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019fa40d-878f-7f90-8e07-e6ba69849eef" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019fa40d-878f-72bf-a2ad-06a391297473" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_dei_DocumentPeriodEndDate_019fa40d-878f-72bf-a2ad-06a391297473" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_LineOfCreditFacilityAvailableAdditionalBorrowingCapacity_019fa40d-878f-7b8c-84a7-92326d63f913" xlink:href="oii-20260930.xsd#oii_LineOfCreditFacilityAvailableAdditionalBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_oii_LineOfCreditFacilityAvailableAdditionalBorrowingCapacity_019fa40d-878f-7b8c-84a7-92326d63f913" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_019fa40d-878f-73ed-8a03-1cdd82bde5b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_019fa40d-878f-73ed-8a03-1cdd82bde5b4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_LineofCreditFacilityPercentofCommitmentsAffectedbyAmendment_019fa40d-878f-7f58-bdf6-01a29c977d85" xlink:href="oii-20260930.xsd#oii_LineofCreditFacilityPercentofCommitmentsAffectedbyAmendment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_oii_LineofCreditFacilityPercentofCommitmentsAffectedbyAmendment_019fa40d-878f-7f58-bdf6-01a29c977d85" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_LineOfCreditFacilityBasisSpreadOnVariableRate_019fa40d-878f-7f4b-a04b-320363b29b48" xlink:href="oii-20260930.xsd#oii_LineOfCreditFacilityBasisSpreadOnVariableRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_oii_LineOfCreditFacilityBasisSpreadOnVariableRate_019fa40d-878f-7f4b-a04b-320363b29b48" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_019fa40d-878f-7efa-afa0-e0d46372067e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_019fa40d-878f-7efa-afa0-e0d46372067e" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_LineofCreditFacilityMaximumCapitalizationRatio_019fa40d-878f-74c3-96ba-15e3d9592d5f" xlink:href="oii-20260930.xsd#oii_LineofCreditFacilityMaximumCapitalizationRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_oii_LineofCreditFacilityMaximumCapitalizationRatio_019fa40d-878f-74c3-96ba-15e3d9592d5f" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNumberOfInstrumentsHeld_019fa40d-878f-7013-acf0-f3a826c4d72a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeNumberOfInstrumentsHeld"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_DerivativeNumberOfInstrumentsHeld_019fa40d-878f-7013-acf0-f3a826c4d72a" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAmountOfHedgedItem_019fa40d-878f-748d-baf0-cdf3f9c09f2b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeAmountOfHedgedItem"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_DerivativeAmountOfHedgedItem_019fa40d-878f-748d-baf0-cdf3f9c09f2b" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_019fa40d-878f-708a-854c-9d94f5503861" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeFixedInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_DerivativeFixedInterestRate_019fa40d-878f-708a-854c-9d94f5503861" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityNotionalAmount_019fa40d-878f-7fc3-b8bf-410c1d9fefa5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLiabilityNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_DerivativeLiabilityNotionalAmount_019fa40d-878f-7fc3-b8bf-410c1d9fefa5" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeVariableInterestRate_019fa40d-878f-7c3d-b93e-e8567037415f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeVariableInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_DerivativeVariableInterestRate_019fa40d-878f-7c3d-b93e-e8567037415f" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsOwnshareLendingArrangementIssuanceCostsAdjustment_019fa40d-878f-7839-9e28-840d854b7976" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredFinanceCostsOwnshareLendingArrangementIssuanceCostsAdjustment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_DeferredFinanceCostsOwnshareLendingArrangementIssuanceCostsAdjustment_019fa40d-878f-7839-9e28-840d854b7976" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_Amortizationdeferredfinancecost_019fa40d-878f-7a3e-a66d-11a301b72467" xlink:href="oii-20260930.xsd#oii_Amortizationdeferredfinancecost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_oii_Amortizationdeferredfinancecost_019fa40d-878f-7a3e-a66d-11a301b72467" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDebtIssuanceCosts_019fa40d-878f-74da-802e-2f0491cf6d62" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsOfDebtIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_PaymentsOfDebtIssuanceCosts_019fa40d-878f-74da-802e-2f0491cf6d62" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfFinancingCosts_019fa40d-878f-7def-a7d1-397a811ba139" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsOfFinancingCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_PaymentsOfFinancingCosts_019fa40d-878f-7def-a7d1-397a811ba139" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_019fa40d-878f-77f2-b8bb-ae0f5ba28a0b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_DebtInstrumentTerm_019fa40d-878f-77f2-b8bb-ae0f5ba28a0b" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateIncreaseDecrease_019fa40d-878f-7267-9502-bc6f77df36d7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_DebtInstrumentInterestRateIncreaseDecrease_019fa40d-878f-7267-9502-bc6f77df36d7" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_PercentageOfFederalFundsRate_019fa40d-878f-7f75-b915-0cbf9d5e16f4" xlink:href="oii-20260930.xsd#oii_PercentageOfFederalFundsRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_oii_PercentageOfFederalFundsRate_019fa40d-878f-7f75-b915-0cbf9d5e16f4" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019fa40d-878f-798b-91f3-53bf5dc7105d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019fa40d-878f-798b-91f3-53bf5dc7105d" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_019fa40d-878f-77c9-96a2-e1e5d2aa121b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_019fa40d-878f-77c9-96a2-e1e5d2aa121b" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_MaximumPermittedLeverageRatio_019fa40d-878f-7402-8c7e-fb5cac8fc37d" xlink:href="oii-20260930.xsd#oii_MaximumPermittedLeverageRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_oii_MaximumPermittedLeverageRatio_019fa40d-878f-7402-8c7e-fb5cac8fc37d" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_FutureMaximumLeverageRatio_019fa40d-878f-772e-8ef4-88251e175bd6" xlink:href="oii-20260930.xsd#oii_FutureMaximumLeverageRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_oii_FutureMaximumLeverageRatio_019fa40d-878f-772e-8ef4-88251e175bd6" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets_019fa40d-878f-7b36-a587-2adb9218308a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets_019fa40d-878f-7b36-a587-2adb9218308a" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfFinancingCosts_019fa40d-878f-7b93-9adc-71e7de1acde9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AmortizationOfFinancingCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_AmortizationOfFinancingCosts_019fa40d-878f-7b93-9adc-71e7de1acde9" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_LiquidityRatio_019fa40d-878f-7822-b60e-76cb189470ec" xlink:href="oii-20260930.xsd#oii_LiquidityRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_oii_LiquidityRatio_019fa40d-878f-7822-b60e-76cb189470ec" xlink:type="arc" order="28"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNetAssetsPercentage_019fa40d-878f-7b26-8086-4eca7974f0aa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeNetAssetsPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_DerivativeNetAssetsPercentage_019fa40d-878f-7b26-8086-4eca7974f0aa" xlink:type="arc" order="29"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentForAmortization_019fa40d-878f-7500-ba8a-2188a1e82965" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentForAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_AdjustmentForAmortization_019fa40d-878f-7500-ba8a-2188a1e82965" xlink:type="arc" order="30"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscount_019fa40d-878f-7373-9d3a-1c539a602379" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentUnamortizedDiscount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscount_019fa40d-878f-7373-9d3a-1c539a602379" xlink:type="arc" order="31"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfDebtDiscountPremium_019fa40d-878f-78f5-89b9-5e28a0a16263" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AmortizationOfDebtDiscountPremium"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_AmortizationOfDebtDiscountPremium_019fa40d-878f-78f5-89b9-5e28a0a16263" xlink:type="arc" order="32"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_RevolvingCreditFacilityAgeOfNetTangibleAssets_019fa40d-878f-75ef-a65e-5f5aa795098c" xlink:href="oii-20260930.xsd#oii_RevolvingCreditFacilityAgeOfNetTangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_oii_RevolvingCreditFacilityAgeOfNetTangibleAssets_019fa40d-878f-75ef-a65e-5f5aa795098c" xlink:type="arc" order="33"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRepurchaseAmount_019fa40d-878f-7528-a9c7-3e880ae20781" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentRepurchaseAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_DebtInstrumentRepurchaseAmount_019fa40d-878f-7528-a9c7-3e880ae20781" xlink:type="arc" order="34"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRepurchasedFaceAmount_019fa40d-878f-7512-b0fd-7148ee6443f7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentRepurchasedFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_DebtInstrumentRepurchasedFaceAmount_019fa40d-878f-7512-b0fd-7148ee6443f7" xlink:type="arc" order="35"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfDebt_019fa40d-878f-7caa-a8e1-84e0c9ca4adf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfDebt_019fa40d-878f-7caa-a8e1-84e0c9ca4adf" xlink:type="arc" order="36"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherBorrowings_019fa40d-878f-7a9f-9ff6-bc33a385870c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_OtherBorrowings_019fa40d-878f-7a9f-9ff6-bc33a385870c" xlink:type="arc" order="37"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_MaxiumumAmountOfBorrowingUnderIndentureForSeniorDebt_019fa40d-878f-7b55-baac-46b177ff3e61" xlink:href="oii-20260930.xsd#oii_MaxiumumAmountOfBorrowingUnderIndentureForSeniorDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_oii_MaxiumumAmountOfBorrowingUnderIndentureForSeniorDebt_019fa40d-878f-7b55-baac-46b177ff3e61" xlink:type="arc" order="38"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentQuarterlyReport_019fa40d-878f-78a5-840c-3a8cd68adbcb" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentQuarterlyReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_dei_DocumentQuarterlyReport_019fa40d-878f-78a5-840c-3a8cd68adbcb" xlink:type="arc" order="39"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_GrossProceedsFromDebt_019fa40d-878f-7b42-9644-42de6ec7dd1b" xlink:href="oii-20260930.xsd#oii_GrossProceedsFromDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_oii_GrossProceedsFromDebt_019fa40d-878f-7b42-9644-42de6ec7dd1b" xlink:type="arc" order="40"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_01a0eec1-34be-7d99-a3bc-8d0e8a44c31b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_01a0eec1-34be-7d99-a3bc-8d0e8a44c31b" xlink:type="arc" order="41"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_DebtExtinguishmentCostMakeWholePremium_01a0eec3-60ce-7acf-a483-bfa11a6bd373" xlink:href="oii-20260930.xsd#oii_DebtExtinguishmentCostMakeWholePremium"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_oii_DebtExtinguishmentCostMakeWholePremium_01a0eec3-60ce-7acf-a483-bfa11a6bd373" xlink:type="arc" order="42"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WriteOffOfDeferredDebtIssuanceCost_01a0eec6-d17c-77d8-876d-101826900358" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WriteOffOfDeferredDebtIssuanceCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_WriteOffOfDeferredDebtIssuanceCost_01a0eec6-d17c-77d8-876d-101826900358" xlink:type="arc" order="43"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestExpenseOfferingCost_01a14b42-e536-7c0d-9b33-566c99c988e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestExpenseOfferingCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_NoninterestExpenseOfferingCost_01a14b42-e536-7c0d-9b33-566c99c988e3" xlink:type="arc" order="44"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_01a14b4d-eacc-7127-9238-ce0da80a2a80" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_01a14b4d-eacc-7127-9238-ce0da80a2a80" xlink:type="arc" order="45"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDebtNetOfIssuanceCosts_01a14b8f-69a9-739e-932f-4cc54e77718b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromDebtNetOfIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_us-gaap_ProceedsFromDebtNetOfIssuanceCosts_01a14b8f-69a9-739e-932f-4cc54e77718b" xlink:type="arc" order="46"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_DebtSublimit_01a14fc9-75a9-7795-aa81-e9227cccc54f" xlink:href="oii-20260930.xsd#oii_DebtSublimit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_oii_DebtSublimit_01a14fc9-75a9-7795-aa81-e9227cccc54f" xlink:type="arc" order="47"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_DebtInstrumentBaseRateLoanRates_01a14fca-7115-7682-b457-01409024ca9b" xlink:href="oii-20260930.xsd#oii_DebtInstrumentBaseRateLoanRates"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019fa40d-878f-7d3f-aac1-edecbce0a4b2" xlink:to="loc_oii_DebtInstrumentBaseRateLoanRates_01a14fca-7115-7682-b457-01409024ca9b" xlink:type="arc" order="48"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/CommitmentsAndContingenciesNarrativeDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#CommitmentsAndContingenciesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/CommitmentsAndContingenciesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_019fa40d-878f-75c4-8531-c0b2623bad4d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_LossContingenciesTable_019fa40d-878f-75c4-8531-c0b2623bad4d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019fa40d-878f-7c97-bb3c-e6900855502a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_019fa40d-878f-75c4-8531-c0b2623bad4d" xlink:to="loc_us-gaap_DebtInstrumentAxis_019fa40d-878f-7c97-bb3c-e6900855502a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-7c97-bb3c-e6900855502a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019fa40d-878f-7c97-bb3c-e6900855502a" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-7c97-bb3c-e6900855502a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-7fde-9d57-815ab2dd3e1b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019fa40d-878f-7c97-bb3c-e6900855502a" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-7fde-9d57-815ab2dd3e1b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SeniorNotesdue2024Member_019fa40d-878f-70f8-887b-e0519ae246c7" xlink:href="oii-20260930.xsd#oii_SeniorNotesdue2024Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-7fde-9d57-815ab2dd3e1b" xlink:to="loc_oii_SeniorNotesdue2024Member_019fa40d-878f-70f8-887b-e0519ae246c7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_019fa40d-878f-7a28-9ae7-8d7b7020cfaa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_019fa40d-878f-75c4-8531-c0b2623bad4d" xlink:to="loc_us-gaap_VariableRateAxis_019fa40d-878f-7a28-9ae7-8d7b7020cfaa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_019fa40d-878f-7a28-9ae7-8d7b7020cfaa_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_019fa40d-878f-7a28-9ae7-8d7b7020cfaa" xlink:to="loc_us-gaap_VariableRateDomain_019fa40d-878f-7a28-9ae7-8d7b7020cfaa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_019fa40d-878f-73ca-8e39-7af849157090" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_019fa40d-878f-7a28-9ae7-8d7b7020cfaa" xlink:to="loc_us-gaap_VariableRateDomain_019fa40d-878f-73ca-8e39-7af849157090" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019fa40d-878f-7784-a16a-b166afd6e4ec" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_019fa40d-878f-75c4-8531-c0b2623bad4d" xlink:to="loc_srt_RangeAxis_019fa40d-878f-7784-a16a-b166afd6e4ec" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa40d-878f-7784-a16a-b166afd6e4ec_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019fa40d-878f-7784-a16a-b166afd6e4ec" xlink:to="loc_srt_RangeMember_019fa40d-878f-7784-a16a-b166afd6e4ec_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa40d-878f-72a7-a3fb-d3fc3da3b777" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019fa40d-878f-7784-a16a-b166afd6e4ec" xlink:to="loc_srt_RangeMember_019fa40d-878f-72a7-a3fb-d3fc3da3b777" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019fa40d-878f-7c96-a550-be141baa8f61" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fa40d-878f-72a7-a3fb-d3fc3da3b777" xlink:to="loc_srt_MinimumMember_019fa40d-878f-7c96-a550-be141baa8f61" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019fa40d-878f-7f5c-a3c9-4ac42cf2d680" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fa40d-878f-72a7-a3fb-d3fc3da3b777" xlink:to="loc_srt_MaximumMember_019fa40d-878f-7f5c-a3c9-4ac42cf2d680" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_019fa40d-878f-7c52-95e5-ffe43c5c6645" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_019fa40d-878f-75c4-8531-c0b2623bad4d" xlink:to="loc_srt_StatementGeographicalAxis_019fa40d-878f-7c52-95e5-ffe43c5c6645" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019fa40d-878f-7c52-95e5-ffe43c5c6645_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_019fa40d-878f-7c52-95e5-ffe43c5c6645" xlink:to="loc_srt_SegmentGeographicalDomain_019fa40d-878f-7c52-95e5-ffe43c5c6645_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019fa40d-878f-7968-af0e-b9ad094b9173" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_019fa40d-878f-7c52-95e5-ffe43c5c6645" xlink:to="loc_srt_SegmentGeographicalDomain_019fa40d-878f-7968-af0e-b9ad094b9173" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_AOA_019fa40d-878f-783f-b009-bcecb1a5d47b" xlink:href="https://xbrl.sec.gov/currency/2026/currency-2026.xsd#currency_AOA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-878f-7968-af0e-b9ad094b9173" xlink:to="loc_currency_AOA_019fa40d-878f-783f-b009-bcecb1a5d47b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_BRL_019fa40d-878f-724c-b0fa-c6b828d68120" xlink:href="https://xbrl.sec.gov/currency/2026/currency-2026.xsd#currency_BRL"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-878f-7968-af0e-b9ad094b9173" xlink:to="loc_currency_BRL_019fa40d-878f-724c-b0fa-c6b828d68120" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_AO_019fa40d-878f-710c-af8c-30f18f839c31" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_AO"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019fa40d-878f-7968-af0e-b9ad094b9173" xlink:to="loc_country_AO_019fa40d-878f-710c-af8c-30f18f839c31" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fa40d-878f-7ca4-aece-9acebf2a9dc6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_019fa40d-878f-75c4-8531-c0b2623bad4d" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fa40d-878f-7ca4-aece-9acebf2a9dc6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fa40d-878f-7ca4-aece-9acebf2a9dc6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fa40d-878f-7ca4-aece-9acebf2a9dc6" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fa40d-878f-7ca4-aece-9acebf2a9dc6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fa40d-878f-7983-b914-25abebe469a3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fa40d-878f-7ca4-aece-9acebf2a9dc6" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fa40d-878f-7983-b914-25abebe469a3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019fa40d-878f-7f4a-a892-f947d32d4e8f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fa40d-878f-7983-b914-25abebe469a3" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019fa40d-878f-7f4a-a892-f947d32d4e8f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CurrencyAxis_019fa40d-878f-7979-ba15-30e799501d10" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CurrencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_019fa40d-878f-75c4-8531-c0b2623bad4d" xlink:to="loc_srt_CurrencyAxis_019fa40d-878f-7979-ba15-30e799501d10" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_AllCurrenciesDomain_019fa40d-878f-7979-ba15-30e799501d10_default" xlink:href="https://xbrl.sec.gov/currency/2026/currency-2026.xsd#currency_AllCurrenciesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CurrencyAxis_019fa40d-878f-7979-ba15-30e799501d10" xlink:to="loc_currency_AllCurrenciesDomain_019fa40d-878f-7979-ba15-30e799501d10_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_AllCurrenciesDomain_019fa40d-878f-7b9e-a33e-a990c8f3d144" xlink:href="https://xbrl.sec.gov/currency/2026/currency-2026.xsd#currency_AllCurrenciesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CurrencyAxis_019fa40d-878f-7979-ba15-30e799501d10" xlink:to="loc_currency_AllCurrenciesDomain_019fa40d-878f-7b9e-a33e-a990c8f3d144" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_BRL_019fa40d-878f-7cb3-9c81-1c8b7511bef2" xlink:href="https://xbrl.sec.gov/currency/2026/currency-2026.xsd#currency_BRL"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_currency_AllCurrenciesDomain_019fa40d-878f-7b9e-a33e-a990c8f3d144" xlink:to="loc_currency_BRL_019fa40d-878f-7cb3-9c81-1c8b7511bef2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_AOA_019fa40d-878f-7f57-82be-be0ba11d38dd" xlink:href="https://xbrl.sec.gov/currency/2026/currency-2026.xsd#currency_AOA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_currency_AllCurrenciesDomain_019fa40d-878f-7b9e-a33e-a990c8f3d144" xlink:to="loc_currency_AOA_019fa40d-878f-7f57-82be-be0ba11d38dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InformationByCategoryOfDebtSecurityAxis_019fa40d-878f-79bf-b9dd-a118a44c7ec3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InformationByCategoryOfDebtSecurityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_019fa40d-878f-75c4-8531-c0b2623bad4d" xlink:to="loc_us-gaap_InformationByCategoryOfDebtSecurityAxis_019fa40d-878f-79bf-b9dd-a118a44c7ec3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCategoriesOfInvestmentsDomain_019fa40d-878f-79bf-b9dd-a118a44c7ec3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCategoriesOfInvestmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InformationByCategoryOfDebtSecurityAxis_019fa40d-878f-79bf-b9dd-a118a44c7ec3" xlink:to="loc_us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCategoriesOfInvestmentsDomain_019fa40d-878f-79bf-b9dd-a118a44c7ec3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCategoriesOfInvestmentsDomain_019fa40d-878f-73d7-a7c6-9448c3da1af4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCategoriesOfInvestmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InformationByCategoryOfDebtSecurityAxis_019fa40d-878f-79bf-b9dd-a118a44c7ec3" xlink:to="loc_us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCategoriesOfInvestmentsDomain_019fa40d-878f-73d7-a7c6-9448c3da1af4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BondsMember_019fa40d-878f-7588-a7cf-6c2294275f11" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BondsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCategoriesOfInvestmentsDomain_019fa40d-878f-73d7-a7c6-9448c3da1af4" xlink:to="loc_us-gaap_BondsMember_019fa40d-878f-7588-a7cf-6c2294275f11" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeographicDistributionAxis_019fa40d-878f-757d-929a-a5aa90e2d732" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GeographicDistributionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_019fa40d-878f-75c4-8531-c0b2623bad4d" xlink:to="loc_us-gaap_GeographicDistributionAxis_019fa40d-878f-757d-929a-a5aa90e2d732" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeographicDistributionDomain_019fa40d-878f-757d-929a-a5aa90e2d732_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GeographicDistributionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GeographicDistributionAxis_019fa40d-878f-757d-929a-a5aa90e2d732" xlink:to="loc_us-gaap_GeographicDistributionDomain_019fa40d-878f-757d-929a-a5aa90e2d732_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeographicDistributionDomain_019fa40d-878f-7a8d-af6c-dec20e319ba6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GeographicDistributionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GeographicDistributionAxis_019fa40d-878f-757d-929a-a5aa90e2d732" xlink:to="loc_us-gaap_GeographicDistributionDomain_019fa40d-878f-7a8d-af6c-dec20e319ba6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_AO_019fa40d-878f-7400-bcc4-3f1594237440" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_AO"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GeographicDistributionDomain_019fa40d-878f-7a8d-af6c-dec20e319ba6" xlink:to="loc_country_AO_019fa40d-878f-7400-bcc4-3f1594237440" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-878f-7633-a024-4c52f03dd94b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_019fa40d-878f-75c4-8531-c0b2623bad4d" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-878f-7633-a024-4c52f03dd94b" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-878f-7633-a024-4c52f03dd94b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-878f-7633-a024-4c52f03dd94b" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-878f-7633-a024-4c52f03dd94b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-878f-7b74-86ea-069d36e8669a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-878f-7633-a024-4c52f03dd94b" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-878f-7b74-86ea-069d36e8669a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_ManufacturedProductsMemberMember_019fa40d-878f-71c5-9121-2f01fc668c98" xlink:href="oii-20260930.xsd#oii_ManufacturedProductsMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-7b74-86ea-069d36e8669a" xlink:to="loc_oii_ManufacturedProductsMemberMember_019fa40d-878f-71c5-9121-2f01fc668c98" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableFairValueDisclosure_019fa40d-878f-7613-8df1-7b55ec264f15" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesPayableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_NotesPayableFairValueDisclosure_019fa40d-878f-7613-8df1-7b55ec264f15" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNumberOfInstrumentsHeld_019fa40d-878f-7001-af00-8b1d9c14f46c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeNumberOfInstrumentsHeld"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_DerivativeNumberOfInstrumentsHeld_019fa40d-878f-7001-af00-8b1d9c14f46c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAmountOfHedgedItem_019fa40d-878f-7720-a088-e775ff986d5e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeAmountOfHedgedItem"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_DerivativeAmountOfHedgedItem_019fa40d-878f-7720-a088-e775ff986d5e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_019fa40d-878f-7584-a0f5-292aac702ef1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeFixedInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_DerivativeFixedInterestRate_019fa40d-878f-7584-a0f5-292aac702ef1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeVariableInterestRate_019fa40d-878f-74aa-bd3c-f7c89945f829" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeVariableInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_DerivativeVariableInterestRate_019fa40d-878f-74aa-bd3c-f7c89945f829" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityNotionalAmount_019fa40d-878f-765d-95de-34c263d7f46c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLiabilityNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_DerivativeLiabilityNotionalAmount_019fa40d-878f-765d-95de-34c263d7f46c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_019fa40d-878f-7c2c-9345-ca268622eb80" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_019fa40d-878f-7c2c-9345-ca268622eb80" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019fa40d-878f-7960-babc-5a098ea1759a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019fa40d-878f-7960-babc-5a098ea1759a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt_019fa40d-878f-76ad-ad8d-a65aa40a980b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt_019fa40d-878f-76ad-ad8d-a65aa40a980b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_019fa40d-878f-7c10-aa1a-f358507fa428" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_019fa40d-878f-7c10-aa1a-f358507fa428" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsFairValueDisclosure_019fa40d-878f-7fe0-9796-1f2b0ce976b0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_InvestmentsFairValueDisclosure_019fa40d-878f-7fe0-9796-1f2b0ce976b0" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedGain_019fa40d-878f-7429-9025-5253e886afe7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleRealizedGain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedGain_019fa40d-878f-7429-9025-5253e886afe7" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesGrossUnrealizedGain_019fa40d-878f-7536-ae0a-541d692418b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleDebtSecuritiesGrossUnrealizedGain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesGrossUnrealizedGain_019fa40d-878f-7536-ae0a-541d692418b5" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_AccountsReceivableAndContractAssetsContingency_019fa40d-878f-7271-8148-776b7a7d90f6" xlink:href="oii-20260930.xsd#oii_AccountsReceivableAndContractAssetsContingency"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_oii_AccountsReceivableAndContractAssetsContingency_019fa40d-878f-7271-8148-776b7a7d90f6" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyEstimateOfPossibleLoss_019fa40d-878f-7546-8cfb-b257d5e04b16" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingencyEstimateOfPossibleLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_LossContingencyEstimateOfPossibleLoss_019fa40d-878f-7546-8cfb-b257d5e04b16" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyAccrualAtCarryingValue_019fa40d-878f-7e99-9ef6-4f455332a28c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingencyAccrualAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_LossContingencyAccrualAtCarryingValue_019fa40d-878f-7e99-9ef6-4f455332a28c" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyAccrualCarryingValuePeriodIncreaseDecrease_019fa40d-878f-7a66-80fa-5ebe5d514341" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingencyAccrualCarryingValuePeriodIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_LossContingencyAccrualCarryingValuePeriodIncreaseDecrease_019fa40d-878f-7a66-80fa-5ebe5d514341" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_019fa40d-878f-7741-96c5-30d4e1d8bf4b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_019fa40d-878f-7741-96c5-30d4e1d8bf4b" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestments_019fa40d-878f-7690-b8dd-4469e0ea15f7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_ShortTermInvestments_019fa40d-878f-7690-b8dd-4469e0ea15f7" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_019fa40d-878f-7cd6-9842-d04bf76d3b0e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_019fa40d-878f-7cd6-9842-d04bf76d3b0e" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAndHeldToMaturityFairValue_019fa40d-878f-7449-b004-1ccac7edb80c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleAndHeldToMaturityFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019fa40d-878f-7734-9200-95c6ddab10ee" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAndHeldToMaturityFairValue_019fa40d-878f-7449-b004-1ccac7edb80c" xlink:type="arc" order="20"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/EarningsLossPerShareStockBasedCompensationandShareRepurchasePlanDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#EarningsLossPerShareStockBasedCompensationandShareRepurchasePlanDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/EarningsLossPerShareStockBasedCompensationandShareRepurchasePlanDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_oii_ShareholdersEquityEarningsPerShareAndStockBasedCompensationLineItems_019fa40d-878f-7bf4-8d61-a54d1c6e5f45" xlink:href="oii-20260930.xsd#oii_ShareholdersEquityEarningsPerShareAndStockBasedCompensationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_ShareholdersEquityEarningsPerShareAndStockBasedCompensationTable_019fa40d-878f-7263-8ee1-c4ce35c9d748" xlink:href="oii-20260930.xsd#oii_ShareholdersEquityEarningsPerShareAndStockBasedCompensationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_oii_ShareholdersEquityEarningsPerShareAndStockBasedCompensationLineItems_019fa40d-878f-7bf4-8d61-a54d1c6e5f45" xlink:to="loc_oii_ShareholdersEquityEarningsPerShareAndStockBasedCompensationTable_019fa40d-878f-7263-8ee1-c4ce35c9d748" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019fa40d-878f-705e-aff1-2c8e4e1d4715" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_oii_ShareholdersEquityEarningsPerShareAndStockBasedCompensationTable_019fa40d-878f-7263-8ee1-c4ce35c9d748" xlink:to="loc_us-gaap_AwardTypeAxis_019fa40d-878f-705e-aff1-2c8e4e1d4715" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019fa40d-878f-705e-aff1-2c8e4e1d4715_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019fa40d-878f-705e-aff1-2c8e4e1d4715" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019fa40d-878f-705e-aff1-2c8e4e1d4715_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019fa40d-878f-7da0-a83e-c7b29a3dd182" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019fa40d-878f-705e-aff1-2c8e4e1d4715" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019fa40d-878f-7da0-a83e-c7b29a3dd182" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_019fa40d-878f-7e1d-b08a-6f8e74342053" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019fa40d-878f-7da0-a83e-c7b29a3dd182" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_019fa40d-878f-7e1d-b08a-6f8e74342053" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_019fa40d-878f-778c-b722-d7a54f62ab0f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019fa40d-878f-7da0-a83e-c7b29a3dd182" xlink:to="loc_us-gaap_PerformanceSharesMember_019fa40d-878f-778c-b722-d7a54f62ab0f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019fa40d-878f-74ce-bdae-ed578035a476" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_oii_ShareholdersEquityEarningsPerShareAndStockBasedCompensationTable_019fa40d-878f-7263-8ee1-c4ce35c9d748" xlink:to="loc_srt_RangeAxis_019fa40d-878f-74ce-bdae-ed578035a476" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa40d-878f-74ce-bdae-ed578035a476_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019fa40d-878f-74ce-bdae-ed578035a476" xlink:to="loc_srt_RangeMember_019fa40d-878f-74ce-bdae-ed578035a476_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa40d-878f-785e-baf5-085b5f554956" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019fa40d-878f-74ce-bdae-ed578035a476" xlink:to="loc_srt_RangeMember_019fa40d-878f-785e-baf5-085b5f554956" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019fa40d-878f-7933-83ba-ecb641ac6e02" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fa40d-878f-785e-baf5-085b5f554956" xlink:to="loc_srt_MaximumMember_019fa40d-878f-7933-83ba-ecb641ac6e02" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardTermsOfAward_019fa40d-878f-7213-b3fa-bb37c70aadf6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardTermsOfAward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oii_ShareholdersEquityEarningsPerShareAndStockBasedCompensationLineItems_019fa40d-878f-7bf4-8d61-a54d1c6e5f45" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardTermsOfAward_019fa40d-878f-7213-b3fa-bb37c70aadf6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019fa40d-878f-79fb-bbc1-4180e2592423" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oii_ShareholdersEquityEarningsPerShareAndStockBasedCompensationLineItems_019fa40d-878f-7bf4-8d61-a54d1c6e5f45" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019fa40d-878f-79fb-bbc1-4180e2592423" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_019fa40d-878f-707d-bc69-b423e581b160" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oii_ShareholdersEquityEarningsPerShareAndStockBasedCompensationLineItems_019fa40d-878f-7bf4-8d61-a54d1c6e5f45" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_019fa40d-878f-707d-bc69-b423e581b160" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased_019fa40d-878f-7d72-b834-075a4c4aedba" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oii_ShareholdersEquityEarningsPerShareAndStockBasedCompensationLineItems_019fa40d-878f-7bf4-8d61-a54d1c6e5f45" xlink:to="loc_srt_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased_019fa40d-878f-7d72-b834-075a4c4aedba" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_StockRepurchaseProgramTotalNumberofSharesRepurchasedToDate_019fa40d-878f-72b8-a3c1-4eb935b83233" xlink:href="oii-20260930.xsd#oii_StockRepurchaseProgramTotalNumberofSharesRepurchasedToDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oii_ShareholdersEquityEarningsPerShareAndStockBasedCompensationLineItems_019fa40d-878f-7bf4-8d61-a54d1c6e5f45" xlink:to="loc_oii_StockRepurchaseProgramTotalNumberofSharesRepurchasedToDate_019fa40d-878f-72b8-a3c1-4eb935b83233" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_019fa40d-878f-73e5-ac64-af3b4a9578cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oii_ShareholdersEquityEarningsPerShareAndStockBasedCompensationLineItems_019fa40d-878f-7bf4-8d61-a54d1c6e5f45" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_019fa40d-878f-73e5-ac64-af3b4a9578cb" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_019fa40d-878f-7e2e-ba9d-902f605fcdfa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oii_ShareholdersEquityEarningsPerShareAndStockBasedCompensationLineItems_019fa40d-878f-7bf4-8d61-a54d1c6e5f45" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_019fa40d-878f-7e2e-ba9d-902f605fcdfa" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StockRepurchaseProgramAuthorizedAmount1_019fa40d-878f-7816-84d3-dd40fc2d65fa" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StockRepurchaseProgramAuthorizedAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oii_ShareholdersEquityEarningsPerShareAndStockBasedCompensationLineItems_019fa40d-878f-7bf4-8d61-a54d1c6e5f45" xlink:to="loc_srt_StockRepurchaseProgramAuthorizedAmount1_019fa40d-878f-7816-84d3-dd40fc2d65fa" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockSharesAcquired_019fa40d-878f-7542-afa2-04a805790a1f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockSharesAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oii_ShareholdersEquityEarningsPerShareAndStockBasedCompensationLineItems_019fa40d-878f-7bf4-8d61-a54d1c6e5f45" xlink:to="loc_us-gaap_TreasuryStockSharesAcquired_019fa40d-878f-7542-afa2-04a805790a1f" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/IncomeTaxesNarrativeDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#IncomeTaxesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/IncomeTaxesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxContingencyLineItems_019fa40d-878f-736f-9495-5186e8215d28" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxContingencyLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxContingencyTable_019fa40d-878f-79aa-b20a-26178937ebbf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxContingencyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_019fa40d-878f-736f-9495-5186e8215d28" xlink:to="loc_us-gaap_IncomeTaxContingencyTable_019fa40d-878f-79aa-b20a-26178937ebbf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxPeriodAxis_019fa40d-878f-7778-81f6-b5ce26496e44" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TaxPeriodAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxContingencyTable_019fa40d-878f-79aa-b20a-26178937ebbf" xlink:to="loc_us-gaap_TaxPeriodAxis_019fa40d-878f-7778-81f6-b5ce26496e44" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxPeriodDomain_019fa40d-878f-7778-81f6-b5ce26496e44_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TaxPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TaxPeriodAxis_019fa40d-878f-7778-81f6-b5ce26496e44" xlink:to="loc_us-gaap_TaxPeriodDomain_019fa40d-878f-7778-81f6-b5ce26496e44_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxPeriodDomain_019fa40d-878f-7bbd-afc3-fe8b9f06f49c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TaxPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TaxPeriodAxis_019fa40d-878f-7778-81f6-b5ce26496e44" xlink:to="loc_us-gaap_TaxPeriodDomain_019fa40d-878f-7bbd-afc3-fe8b9f06f49c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxYear2014Member_019fa40d-878f-7386-96e1-d98dd9fdfa2c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TaxYear2014Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_019fa40d-878f-7bbd-afc3-fe8b9f06f49c" xlink:to="loc_us-gaap_TaxYear2014Member_019fa40d-878f-7386-96e1-d98dd9fdfa2c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxYear2013Member_019fa40d-878f-70b7-96c9-1d883f7fd093" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TaxYear2013Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_019fa40d-878f-7bbd-afc3-fe8b9f06f49c" xlink:to="loc_us-gaap_TaxYear2013Member_019fa40d-878f-70b7-96c9-1d883f7fd093" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019fa40d-878f-779e-9aab-c5667b515e6f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxContingencyTable_019fa40d-878f-79aa-b20a-26178937ebbf" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019fa40d-878f-779e-9aab-c5667b515e6f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_019fa40d-878f-779e-9aab-c5667b515e6f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019fa40d-878f-779e-9aab-c5667b515e6f" xlink:to="loc_us-gaap_ReceivableTypeDomain_019fa40d-878f-779e-9aab-c5667b515e6f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_019fa40d-878f-795c-b64d-fdc09a72ac46" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019fa40d-878f-779e-9aab-c5667b515e6f" xlink:to="loc_us-gaap_ReceivableTypeDomain_019fa40d-878f-795c-b64d-fdc09a72ac46" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_CARESActTaxRefundMember_019fa40d-878f-7a56-b2a4-162d73b2d451" xlink:href="oii-20260930.xsd#oii_CARESActTaxRefundMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_019fa40d-878f-795c-b64d-fdc09a72ac46" xlink:to="loc_oii_CARESActTaxRefundMember_019fa40d-878f-7a56-b2a4-162d73b2d451" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019fa40d-878f-7231-8b49-7cb64732972d" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_019fa40d-878f-736f-9495-5186e8215d28" xlink:to="loc_dei_DocumentPeriodEndDate_019fa40d-878f-7231-8b49-7cb64732972d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxAdjustmentsSettlementsAndUnusualProvisions_019fa40d-878f-7213-a0f3-adb2fc66b718" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TaxAdjustmentsSettlementsAndUnusualProvisions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_019fa40d-878f-736f-9495-5186e8215d28" xlink:to="loc_us-gaap_TaxAdjustmentsSettlementsAndUnusualProvisions_019fa40d-878f-7213-a0f3-adb2fc66b718" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_UnrecognizedTaxBenefitsExpenseProbabilityThresholdofRealizingforTaxBenefitsExpenseRecognitionMinimumPercentage_019fa40d-878f-75c0-b54a-d8596f849dc8" xlink:href="oii-20260930.xsd#oii_UnrecognizedTaxBenefitsExpenseProbabilityThresholdofRealizingforTaxBenefitsExpenseRecognitionMinimumPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_019fa40d-878f-736f-9495-5186e8215d28" xlink:to="loc_oii_UnrecognizedTaxBenefitsExpenseProbabilityThresholdofRealizingforTaxBenefitsExpenseRecognitionMinimumPercentage_019fa40d-878f-75c0-b54a-d8596f849dc8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_EffectiveincometaxratereconciliationCARESAct_019fa40d-878f-75e4-83f1-4a989dd56e0f" xlink:href="oii-20260930.xsd#oii_EffectiveincometaxratereconciliationCARESAct"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_019fa40d-878f-736f-9495-5186e8215d28" xlink:to="loc_oii_EffectiveincometaxratereconciliationCARESAct_019fa40d-878f-75e4-83f1-4a989dd56e0f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_EffectiveIncomeTaxRateReconciliationUncertainTaxPosition_019fa40d-878f-77fa-9eab-30d4b40a1b2e" xlink:href="oii-20260930.xsd#oii_EffectiveIncomeTaxRateReconciliationUncertainTaxPosition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_019fa40d-878f-736f-9495-5186e8215d28" xlink:to="loc_oii_EffectiveIncomeTaxRateReconciliationUncertainTaxPosition_019fa40d-878f-77fa-9eab-30d4b40a1b2e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount_019fa40d-878f-7f35-8663-03c9ad9b55c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_019fa40d-878f-736f-9495-5186e8215d28" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount_019fa40d-878f-7f35-8663-03c9ad9b55c7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationOtherAdjustments_019fa40d-878f-7257-bbaa-6aecd09a1d70" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxReconciliationOtherAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_019fa40d-878f-736f-9495-5186e8215d28" xlink:to="loc_us-gaap_IncomeTaxReconciliationOtherAdjustments_019fa40d-878f-7257-bbaa-6aecd09a1d70" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIncomeTaxRefunds_019fa40d-878f-7c90-9bb3-a6baffa4163e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIncomeTaxRefunds"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_019fa40d-878f-736f-9495-5186e8215d28" xlink:to="loc_us-gaap_ProceedsFromIncomeTaxRefunds_019fa40d-878f-7c90-9bb3-a6baffa4163e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_NoncashtaxbenefitfromCARESAct_019fa40d-878f-7021-b504-190c97822630" xlink:href="oii-20260930.xsd#oii_NoncashtaxbenefitfromCARESAct"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_019fa40d-878f-736f-9495-5186e8215d28" xlink:to="loc_oii_NoncashtaxbenefitfromCARESAct_019fa40d-878f-7021-b504-190c97822630" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUncertainTaxPositionsNoncurrent_019fa40d-878f-7ba5-a91b-2c3c773fdd60" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilityForUncertainTaxPositionsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_019fa40d-878f-736f-9495-5186e8215d28" xlink:to="loc_us-gaap_LiabilityForUncertainTaxPositionsNoncurrent_019fa40d-878f-7ba5-a91b-2c3c773fdd60" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReceivable_019fa40d-878f-7b8f-9d3d-c2f0f7d49be2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_019fa40d-878f-736f-9495-5186e8215d28" xlink:to="loc_us-gaap_IncomeTaxReceivable_019fa40d-878f-7b8f-9d3d-c2f0f7d49be2" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_NoncashIncomeTaxBenefit_019fa40d-878f-735c-aeda-7090d0d9a5b4" xlink:href="oii-20260930.xsd#oii_NoncashIncomeTaxBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_019fa40d-878f-736f-9495-5186e8215d28" xlink:to="loc_oii_NoncashIncomeTaxBenefit_019fa40d-878f-735c-aeda-7090d0d9a5b4" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_019fa40d-878f-7d28-95d8-5e7dfd76d3aa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_019fa40d-878f-736f-9495-5186e8215d28" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_019fa40d-878f-7d28-95d8-5e7dfd76d3aa" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExaminationLiabilityRefundAdjustmentFromSettlementWithTaxingAuthority_019fa40d-878f-7a7b-a7d3-fff1db63bb77" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExaminationLiabilityRefundAdjustmentFromSettlementWithTaxingAuthority"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_019fa40d-878f-736f-9495-5186e8215d28" xlink:to="loc_us-gaap_IncomeTaxExaminationLiabilityRefundAdjustmentFromSettlementWithTaxingAuthority_019fa40d-878f-7a7b-a7d3-fff1db63bb77" xlink:type="arc" order="13"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/IncomeTaxesSummaryOfEarliestTaxYearsOpenToExaminationDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#IncomeTaxesSummaryOfEarliestTaxYearsOpenToExaminationDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/IncomeTaxesSummaryOfEarliestTaxYearsOpenToExaminationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExaminationLineItems_019fa40d-878f-7756-8509-dbca4edfebe1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExaminationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExaminationTable_019fa40d-878f-7eba-801b-e43306dec416" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExaminationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_019fa40d-878f-7756-8509-dbca4edfebe1" xlink:to="loc_us-gaap_IncomeTaxExaminationTable_019fa40d-878f-7eba-801b-e43306dec416" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_019fa40d-878f-7ad3-8faf-220e4a4cf73f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxAuthorityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxExaminationTable_019fa40d-878f-7eba-801b-e43306dec416" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_019fa40d-878f-7ad3-8faf-220e4a4cf73f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_019fa40d-878f-7ad3-8faf-220e4a4cf73f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_019fa40d-878f-7ad3-8faf-220e4a4cf73f" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_019fa40d-878f-7ad3-8faf-220e4a4cf73f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_019fa40d-878f-7365-b552-38a827c215e0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_019fa40d-878f-7ad3-8faf-220e4a4cf73f" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_019fa40d-878f-7365-b552-38a827c215e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DomesticCountryMember_019fa40d-878f-75e5-a7cc-b4c3a763655d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DomesticCountryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019fa40d-878f-7365-b552-38a827c215e0" xlink:to="loc_us-gaap_DomesticCountryMember_019fa40d-878f-75e5-a7cc-b4c3a763655d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_GB_019fa40d-878f-7580-89bf-7c3fbe9de218" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_GB"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019fa40d-878f-7365-b552-38a827c215e0" xlink:to="loc_country_GB_019fa40d-878f-7580-89bf-7c3fbe9de218" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_NO_019fa40d-878f-753a-b872-f431e9fe59e3" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_NO"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019fa40d-878f-7365-b552-38a827c215e0" xlink:to="loc_country_NO_019fa40d-878f-753a-b872-f431e9fe59e3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_AO_019fa40d-878f-7793-bb92-d81930fa5a7a" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_AO"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019fa40d-878f-7365-b552-38a827c215e0" xlink:to="loc_country_AO_019fa40d-878f-7793-bb92-d81930fa5a7a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_BR_019fa40d-878f-7374-9ee4-2ca04aa78a5f" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_BR"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019fa40d-878f-7365-b552-38a827c215e0" xlink:to="loc_country_BR_019fa40d-878f-7374-9ee4-2ca04aa78a5f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_AU_019fa40d-878f-7c7c-9add-2a36adebae47" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_AU"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019fa40d-878f-7365-b552-38a827c215e0" xlink:to="loc_country_AU_019fa40d-878f-7c7c-9add-2a36adebae47" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OpenTaxYear_019fa40d-878f-77af-8973-2bba7352dd57" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OpenTaxYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_019fa40d-878f-7756-8509-dbca4edfebe1" xlink:to="loc_us-gaap_OpenTaxYear_019fa40d-878f-77af-8973-2bba7352dd57" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/AllowanceforCreditLossesDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#AllowanceforCreditLossesDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/AllowanceforCreditLossesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-878f-74ba-a226-3bc0b208c416" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fa40d-878f-7097-bce1-0011c17ce2d7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-878f-74ba-a226-3bc0b208c416" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fa40d-878f-7097-bce1-0011c17ce2d7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-878f-7764-8f51-86d5cd4b7185" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fa40d-878f-7097-bce1-0011c17ce2d7" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-878f-7764-8f51-86d5cd4b7185" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-878f-7764-8f51-86d5cd4b7185_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-878f-7764-8f51-86d5cd4b7185" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-878f-7764-8f51-86d5cd4b7185_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-878f-74e5-aa0b-4a89f3da3945" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019fa40d-878f-7764-8f51-86d5cd4b7185" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-878f-74e5-aa0b-4a89f3da3945" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableMember_019fa40d-878f-7e8b-b948-b7625417252e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019fa40d-878f-74e5-aa0b-4a89f3da3945" xlink:to="loc_us-gaap_AccountsReceivableMember_019fa40d-878f-7e8b-b948-b7625417252e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestReceivable_019fa40d-878f-7b60-add3-c3dbabd5c29f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-878f-74ba-a226-3bc0b208c416" xlink:to="loc_us-gaap_InterestReceivable_019fa40d-878f-7b60-add3-c3dbabd5c29f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_AccountsReceivableAllowanceforCreditLosses_019fa40d-878f-7740-b4cc-18ef53308408" xlink:href="oii-20260930.xsd#oii_AccountsReceivableAllowanceforCreditLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-878f-74ba-a226-3bc0b208c416" xlink:to="loc_oii_AccountsReceivableAllowanceforCreditLosses_019fa40d-878f-7740-b4cc-18ef53308408" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_019fa40d-878f-79fb-b254-f1fb2117deab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fa40d-878f-74ba-a226-3bc0b208c416" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_019fa40d-878f-79fb-b254-f1fb2117deab" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/IntangibleAssetsGoodwillandOtherDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#IntangibleAssetsGoodwillandOtherDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/IntangibleAssetsGoodwillandOtherDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019fa40d-878f-7d0b-93d2-0fd173681149" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019fa40d-878f-7ff3-a204-b0263638395d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019fa40d-878f-7d0b-93d2-0fd173681149" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019fa40d-878f-7ff3-a204-b0263638395d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019fa40d-878f-7cc0-af2f-8a963231662a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019fa40d-878f-7ff3-a204-b0263638395d" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019fa40d-878f-7cc0-af2f-8a963231662a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019fa40d-878f-7cc0-af2f-8a963231662a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019fa40d-878f-7cc0-af2f-8a963231662a" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019fa40d-878f-7cc0-af2f-8a963231662a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019fa40d-878f-7b16-8c60-bee62d4aebd9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019fa40d-878f-7cc0-af2f-8a963231662a" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019fa40d-878f-7b16-8c60-bee62d4aebd9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019fa40d-878f-7dd0-b538-bee30b049594" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019fa40d-878f-7ff3-a204-b0263638395d" xlink:to="loc_srt_ConsolidationItemsAxis_019fa40d-878f-7dd0-b538-bee30b049594" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019fa40d-878f-7dd0-b538-bee30b049594_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019fa40d-878f-7dd0-b538-bee30b049594" xlink:to="loc_srt_ConsolidationItemsDomain_019fa40d-878f-7dd0-b538-bee30b049594_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019fa40d-878f-7fb3-b022-a1ddbbc32255" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019fa40d-878f-7dd0-b538-bee30b049594" xlink:to="loc_srt_ConsolidationItemsDomain_019fa40d-878f-7fb3-b022-a1ddbbc32255" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-878f-7d03-9783-e0cf60df5c81" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019fa40d-878f-7ff3-a204-b0263638395d" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-878f-7d03-9783-e0cf60df5c81" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-878f-7d03-9783-e0cf60df5c81_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-878f-7d03-9783-e0cf60df5c81" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-878f-7d03-9783-e0cf60df5c81_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-878f-734f-9524-b22002ac04e5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-878f-7d03-9783-e0cf60df5c81" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-878f-734f-9524-b22002ac04e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_ManufacturedProductsMemberMember_019fa40d-878f-76dd-89e1-3d9a8644331f" xlink:href="oii-20260930.xsd#oii_ManufacturedProductsMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-734f-9524-b22002ac04e5" xlink:to="loc_oii_ManufacturedProductsMemberMember_019fa40d-878f-76dd-89e1-3d9a8644331f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_OffshoreProjectsGroupMember_019fa40d-878f-7970-8fd8-88d34f906dbd" xlink:href="oii-20260930.xsd#oii_OffshoreProjectsGroupMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-734f-9524-b22002ac04e5" xlink:to="loc_oii_OffshoreProjectsGroupMember_019fa40d-878f-7970-8fd8-88d34f906dbd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_IntegrityManagementsDigitalSolutionsMemberMember_019fa40d-878f-7118-8ac2-9aa86757c208" xlink:href="oii-20260930.xsd#oii_IntegrityManagementsDigitalSolutionsMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-734f-9524-b22002ac04e5" xlink:to="loc_oii_IntegrityManagementsDigitalSolutionsMemberMember_019fa40d-878f-7118-8ac2-9aa86757c208" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SubseaProductsMember_019fa40d-878f-7893-a42c-e53e743e45e1" xlink:href="oii-20260930.xsd#oii_SubseaProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-734f-9524-b22002ac04e5" xlink:to="loc_oii_SubseaProductsMember_019fa40d-878f-7893-a42c-e53e743e45e1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SubseaProjectsMember_019fa40d-878f-7b75-84b2-e0dc51659688" xlink:href="oii-20260930.xsd#oii_SubseaProjectsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-734f-9524-b22002ac04e5" xlink:to="loc_oii_SubseaProjectsMember_019fa40d-878f-7b75-84b2-e0dc51659688" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_AssetIntegrityMember_019fa40d-878f-7d78-b5c8-e72e45750747" xlink:href="oii-20260930.xsd#oii_AssetIntegrityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-734f-9524-b22002ac04e5" xlink:to="loc_oii_AssetIntegrityMember_019fa40d-878f-7d78-b5c8-e72e45750747" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SubseaRoboticsMemberMember_019fa40d-878f-7f72-a30f-19efbf6e7629" xlink:href="oii-20260930.xsd#oii_SubseaRoboticsMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-734f-9524-b22002ac04e5" xlink:to="loc_oii_SubseaRoboticsMemberMember_019fa40d-878f-7f72-a30f-19efbf6e7629" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SubseaProjectsMember_019fa40d-878f-76a3-b52f-22f5f6b0c4bf" xlink:href="oii-20260930.xsd#oii_SubseaProjectsMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_AdvancedTechnologiesMember_019fa40d-878f-797d-9cfc-5a1a70da3cd7" xlink:href="oii-20260930.xsd#oii_AdvancedTechnologiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-734f-9524-b22002ac04e5" xlink:to="loc_oii_AdvancedTechnologiesMember_019fa40d-878f-797d-9cfc-5a1a70da3cd7" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019fa40d-878f-7682-97bc-8adebb16eb8f" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019fa40d-878f-7ff3-a204-b0263638395d" xlink:to="loc_srt_RangeAxis_019fa40d-878f-7682-97bc-8adebb16eb8f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa40d-878f-7682-97bc-8adebb16eb8f_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019fa40d-878f-7682-97bc-8adebb16eb8f" xlink:to="loc_srt_RangeMember_019fa40d-878f-7682-97bc-8adebb16eb8f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa40d-878f-7ff8-8f32-0df06e9db170" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019fa40d-878f-7682-97bc-8adebb16eb8f" xlink:to="loc_srt_RangeMember_019fa40d-878f-7ff8-8f32-0df06e9db170" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019fa40d-878f-73ad-bd41-aab6c5639573" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fa40d-878f-7ff8-8f32-0df06e9db170" xlink:to="loc_srt_MinimumMember_019fa40d-878f-73ad-bd41-aab6c5639573" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019fa40d-878f-760b-9a4f-16a82198d047" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fa40d-878f-7ff8-8f32-0df06e9db170" xlink:to="loc_srt_MaximumMember_019fa40d-878f-760b-9a4f-16a82198d047" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_019fa40d-878f-7762-93d3-16c5f7a8205a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019fa40d-878f-7ff3-a204-b0263638395d" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_019fa40d-878f-7762-93d3-16c5f7a8205a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_019fa40d-878f-7762-93d3-16c5f7a8205a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_019fa40d-878f-7762-93d3-16c5f7a8205a" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_019fa40d-878f-7762-93d3-16c5f7a8205a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_019fa40d-878f-7344-9e83-5d8162db2d74" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_019fa40d-878f-7762-93d3-16c5f7a8205a" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_019fa40d-878f-7344-9e83-5d8162db2d74" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_WeightedaveragememberlowrangeMember_019fa40d-878f-7404-9ddd-be0b01caced8" xlink:href="oii-20260930.xsd#oii_WeightedaveragememberlowrangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019fa40d-878f-7344-9e83-5d8162db2d74" xlink:to="loc_oii_WeightedaveragememberlowrangeMember_019fa40d-878f-7404-9ddd-be0b01caced8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_WeightedAverageMemberHighRangeMember_019fa40d-878f-7d01-9c9a-616a2ba9b262" xlink:href="oii-20260930.xsd#oii_WeightedAverageMemberHighRangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019fa40d-878f-7344-9e83-5d8162db2d74" xlink:to="loc_oii_WeightedAverageMemberHighRangeMember_019fa40d-878f-7d01-9c9a-616a2ba9b262" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputLongTermRevenueGrowthRateMember_019fa40d-878f-7054-8ac0-ede0548fa7b6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputLongTermRevenueGrowthRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019fa40d-878f-7344-9e83-5d8162db2d74" xlink:to="loc_us-gaap_MeasurementInputLongTermRevenueGrowthRateMember_019fa40d-878f-7054-8ac0-ede0548fa7b6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_WeightedaveragememberlowrangeMember_019fa40d-878f-7b8f-a0cf-9b1a53588873" xlink:href="oii-20260930.xsd#oii_WeightedaveragememberlowrangeMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitAxis_019fa40d-878f-7271-b2be-9d1815f74697" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReportingUnitAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019fa40d-878f-7ff3-a204-b0263638395d" xlink:to="loc_us-gaap_ReportingUnitAxis_019fa40d-878f-7271-b2be-9d1815f74697" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitDomain_019fa40d-878f-7271-b2be-9d1815f74697_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReportingUnitDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReportingUnitAxis_019fa40d-878f-7271-b2be-9d1815f74697" xlink:to="loc_us-gaap_ReportingUnitDomain_019fa40d-878f-7271-b2be-9d1815f74697_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitDomain_019fa40d-878f-7b3d-afd0-8e6f922df1d5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReportingUnitDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReportingUnitAxis_019fa40d-878f-7271-b2be-9d1815f74697" xlink:to="loc_us-gaap_ReportingUnitDomain_019fa40d-878f-7b3d-afd0-8e6f922df1d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SDSRosythMember_019fa40d-878f-7392-ae29-0b149ea58205" xlink:href="oii-20260930.xsd#oii_SDSRosythMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportingUnitDomain_019fa40d-878f-7b3d-afd0-8e6f922df1d5" xlink:to="loc_oii_SDSRosythMember_019fa40d-878f-7392-ae29-0b149ea58205" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SDSBrazilMember_019fa40d-878f-7ebf-b0b0-664ca5d41a6a" xlink:href="oii-20260930.xsd#oii_SDSBrazilMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportingUnitDomain_019fa40d-878f-7b3d-afd0-8e6f922df1d5" xlink:to="loc_oii_SDSBrazilMember_019fa40d-878f-7ebf-b0b0-664ca5d41a6a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SubseaProductsAngolaMember_019fa40d-878f-74e6-a15e-c8d6115f1dc9" xlink:href="oii-20260930.xsd#oii_SubseaProductsAngolaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportingUnitDomain_019fa40d-878f-7b3d-afd0-8e6f922df1d5" xlink:to="loc_oii_SubseaProductsAngolaMember_019fa40d-878f-74e6-a15e-c8d6115f1dc9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_ShallowWaterMember_019fa40d-878f-7b59-93a7-f53437704a2d" xlink:href="oii-20260930.xsd#oii_ShallowWaterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportingUnitDomain_019fa40d-878f-7b3d-afd0-8e6f922df1d5" xlink:to="loc_oii_ShallowWaterMember_019fa40d-878f-7b59-93a7-f53437704a2d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_EcosseMember_019fa40d-878f-7777-8973-d5ebf5ff573b" xlink:href="oii-20260930.xsd#oii_EcosseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportingUnitDomain_019fa40d-878f-7b3d-afd0-8e6f922df1d5" xlink:to="loc_oii_EcosseMember_019fa40d-878f-7777-8973-d5ebf5ff573b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_GlobalDataSolutionMember_019fa40d-878f-7079-91e6-501bbd051ad4" xlink:href="oii-20260930.xsd#oii_GlobalDataSolutionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportingUnitDomain_019fa40d-878f-7b3d-afd0-8e6f922df1d5" xlink:to="loc_oii_GlobalDataSolutionMember_019fa40d-878f-7079-91e6-501bbd051ad4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_OceaneeringEntertainmentSystemMember_019fa40d-878f-766a-a66e-4bd663a2f2b3" xlink:href="oii-20260930.xsd#oii_OceaneeringEntertainmentSystemMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportingUnitDomain_019fa40d-878f-7b3d-afd0-8e6f922df1d5" xlink:to="loc_oii_OceaneeringEntertainmentSystemMember_019fa40d-878f-766a-a66e-4bd663a2f2b3" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_OceaneeringAGVSystemMember_019fa40d-878f-754e-aeff-cd88154611f6" xlink:href="oii-20260930.xsd#oii_OceaneeringAGVSystemMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportingUnitDomain_019fa40d-878f-7b3d-afd0-8e6f922df1d5" xlink:to="loc_oii_OceaneeringAGVSystemMember_019fa40d-878f-754e-aeff-cd88154611f6" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_ManufacturedProductsMemberMember_019fa40d-878f-7fc9-8ee2-f490cd0d69e6" xlink:href="oii-20260930.xsd#oii_ManufacturedProductsMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportingUnitDomain_019fa40d-878f-7b3d-afd0-8e6f922df1d5" xlink:to="loc_oii_ManufacturedProductsMemberMember_019fa40d-878f-7fc9-8ee2-f490cd0d69e6" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_OffshoreProjectsGroupMember_019fa40d-878f-7c83-ae4d-2c0c9ad48532" xlink:href="oii-20260930.xsd#oii_OffshoreProjectsGroupMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportingUnitDomain_019fa40d-878f-7b3d-afd0-8e6f922df1d5" xlink:to="loc_oii_OffshoreProjectsGroupMember_019fa40d-878f-7c83-ae4d-2c0c9ad48532" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_IntegrityManagementsDigitalSolutionsMemberMember_019fa40d-878f-7c9d-a9a5-585dabb108e0" xlink:href="oii-20260930.xsd#oii_IntegrityManagementsDigitalSolutionsMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportingUnitDomain_019fa40d-878f-7b3d-afd0-8e6f922df1d5" xlink:to="loc_oii_IntegrityManagementsDigitalSolutionsMemberMember_019fa40d-878f-7c9d-a9a5-585dabb108e0" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AlternativeInvestmentMeasurementInput_019fa40d-878f-77f6-945e-c2d2cebff5a5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AlternativeInvestmentMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019fa40d-878f-7d0b-93d2-0fd173681149" xlink:to="loc_us-gaap_AlternativeInvestmentMeasurementInput_019fa40d-878f-77f6-945e-c2d2cebff5a5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_Impairmentpropertyplantequipment_019fa40d-878f-7f38-bb93-e0023b8df19b" xlink:href="oii-20260930.xsd#oii_Impairmentpropertyplantequipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019fa40d-878f-7d0b-93d2-0fd173681149" xlink:to="loc_oii_Impairmentpropertyplantequipment_019fa40d-878f-7f38-bb93-e0023b8df19b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse_019fa40d-878f-7655-930e-9dada2e40f77" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ImpairmentOfLongLivedAssetsHeldForUse"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019fa40d-878f-7d0b-93d2-0fd173681149" xlink:to="loc_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse_019fa40d-878f-7655-930e-9dada2e40f77" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_019fa40d-878f-79c2-9028-d270e24c678a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_019fa40d-878f-7f23-a56e-e22253284de7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_019fa40d-878f-79c2-9028-d270e24c678a" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_019fa40d-878f-7f23-a56e-e22253284de7" xlink:type="arc" order="2" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019fa40d-878f-7cdc-98a7-be80bfe40edf" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_019fa40d-878f-7f23-a56e-e22253284de7" xlink:to="loc_srt_RangeAxis_019fa40d-878f-7cdc-98a7-be80bfe40edf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa40d-878f-7cdc-98a7-be80bfe40edf_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa40d-878f-797e-88cf-29071b0bcdcf" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019fa40d-878f-7cb3-92a2-453f74015d76" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_019fa40d-878f-7402-af32-df1d4f4d64a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_019fa40d-878f-79c2-9028-d270e24c678a" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_019fa40d-878f-7402-af32-df1d4f4d64a9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AlternativeInvestmentMeasurementInput_019fa40d-878f-75f2-a5e8-595970bbb149" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AlternativeInvestmentMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_019fa40d-878f-79c2-9028-d270e24c678a" xlink:to="loc_us-gaap_AlternativeInvestmentMeasurementInput_019fa40d-878f-75f2-a5e8-595970bbb149" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/SubsequentEventsDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#SubsequentEventsDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/SubsequentEventsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_019fa40d-878f-724c-bc44-13fec8121f55" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_019fa40d-878f-7365-885f-b835b73d6b69" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fa40d-878f-724c-bc44-13fec8121f55" xlink:to="loc_us-gaap_SubsequentEventTable_019fa40d-878f-7365-885f-b835b73d6b69" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019fa40d-878f-7ffd-8e2c-1fdf89fbae2f" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019fa40d-878f-7365-885f-b835b73d6b69" xlink:to="loc_srt_RangeAxis_019fa40d-878f-7ffd-8e2c-1fdf89fbae2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa40d-878f-7ffd-8e2c-1fdf89fbae2f_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019fa40d-878f-7ffd-8e2c-1fdf89fbae2f" xlink:to="loc_srt_RangeMember_019fa40d-878f-7ffd-8e2c-1fdf89fbae2f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa40d-878f-774a-8941-4d2607793276" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019fa40d-878f-7ffd-8e2c-1fdf89fbae2f" xlink:to="loc_srt_RangeMember_019fa40d-878f-774a-8941-4d2607793276" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019fa40d-878f-7293-bbc5-5df4325eb766" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fa40d-878f-774a-8941-4d2607793276" xlink:to="loc_srt_MinimumMember_019fa40d-878f-7293-bbc5-5df4325eb766" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019fa40d-878f-70ec-864c-21ca2f9cf357" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fa40d-878f-774a-8941-4d2607793276" xlink:to="loc_srt_MaximumMember_019fa40d-878f-70ec-864c-21ca2f9cf357" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_019fa40d-878f-76ef-b4e9-39665148d360" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019fa40d-878f-7365-885f-b835b73d6b69" xlink:to="loc_us-gaap_VariableRateAxis_019fa40d-878f-76ef-b4e9-39665148d360" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_019fa40d-878f-76ef-b4e9-39665148d360_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_019fa40d-878f-76ef-b4e9-39665148d360" xlink:to="loc_us-gaap_VariableRateDomain_019fa40d-878f-76ef-b4e9-39665148d360_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_019fa40d-878f-73df-bfcb-1e5ce968a83e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_019fa40d-878f-76ef-b4e9-39665148d360" xlink:to="loc_us-gaap_VariableRateDomain_019fa40d-878f-73df-bfcb-1e5ce968a83e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_019fa40d-878f-761e-a788-b578f097f094" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019fa40d-878f-73df-bfcb-1e5ce968a83e" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_019fa40d-878f-761e-a788-b578f097f094" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BaseRateMember_019fa40d-878f-7b87-b17b-e14d70bb7dd6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BaseRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019fa40d-878f-73df-bfcb-1e5ce968a83e" xlink:to="loc_us-gaap_BaseRateMember_019fa40d-878f-7b87-b17b-e14d70bb7dd6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_019fa40d-878f-7f71-b5b4-c2c2a6700375" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019fa40d-878f-7365-885f-b835b73d6b69" xlink:to="loc_us-gaap_CreditFacilityAxis_019fa40d-878f-7f71-b5b4-c2c2a6700375" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019fa40d-878f-7f71-b5b4-c2c2a6700375_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_019fa40d-878f-7f71-b5b4-c2c2a6700375" xlink:to="loc_us-gaap_CreditFacilityDomain_019fa40d-878f-7f71-b5b4-c2c2a6700375_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019fa40d-878f-7839-9261-77b4c78741e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_019fa40d-878f-7f71-b5b4-c2c2a6700375" xlink:to="loc_us-gaap_CreditFacilityDomain_019fa40d-878f-7839-9261-77b4c78741e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_019fa40d-878f-7bd7-9e99-3420dba1a4e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019fa40d-878f-7839-9261-77b4c78741e1" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_019fa40d-878f-7bd7-9e99-3420dba1a4e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_019fa40d-878f-7607-9ee0-179cbadd7e88" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019fa40d-878f-7839-9261-77b4c78741e1" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_019fa40d-878f-7607-9ee0-179cbadd7e88" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019fa40d-878f-7179-bf9f-dd5e759f9f23" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019fa40d-878f-7839-9261-77b4c78741e1" xlink:to="loc_us-gaap_LineOfCreditMember_019fa40d-878f-7179-bf9f-dd5e759f9f23" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_LineOfCreditAmendmentNo.2July2026Member_019fa40d-878f-775e-895c-acf999c9068d" xlink:href="oii-20260930.xsd#oii_LineOfCreditAmendmentNo.2July2026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019fa40d-878f-7839-9261-77b4c78741e1" xlink:to="loc_oii_LineOfCreditAmendmentNo.2July2026Member_019fa40d-878f-775e-895c-acf999c9068d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_LineOfCreditAmendmentNo.1Sept2023Member_019fa40d-878f-7389-ba95-9ade521aac9e" xlink:href="oii-20260930.xsd#oii_LineOfCreditAmendmentNo.1Sept2023Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019fa40d-878f-7839-9261-77b4c78741e1" xlink:to="loc_oii_LineOfCreditAmendmentNo.1Sept2023Member_019fa40d-878f-7389-ba95-9ade521aac9e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_019fa40d-878f-79b8-8280-46c6167c4ae1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019fa40d-878f-7365-885f-b835b73d6b69" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_019fa40d-878f-79b8-8280-46c6167c4ae1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019fa40d-878f-79b8-8280-46c6167c4ae1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019fa40d-878f-79b8-8280-46c6167c4ae1" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019fa40d-878f-79b8-8280-46c6167c4ae1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019fa40d-878f-764f-b82c-1ee4dd4f7269" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019fa40d-878f-79b8-8280-46c6167c4ae1" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019fa40d-878f-764f-b82c-1ee4dd4f7269" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_019fa40d-878f-7b79-9132-d0210620737b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_019fa40d-878f-764f-b82c-1ee4dd4f7269" xlink:to="loc_us-gaap_SubsequentEventMember_019fa40d-878f-7b79-9132-d0210620737b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019fa40d-878f-7946-906d-5d316a726462" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019fa40d-878f-7365-885f-b835b73d6b69" xlink:to="loc_us-gaap_DebtInstrumentAxis_019fa40d-878f-7946-906d-5d316a726462" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-7946-906d-5d316a726462_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019fa40d-878f-7946-906d-5d316a726462" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-7946-906d-5d316a726462_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-70ce-be24-c6f911510072" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019fa40d-878f-7946-906d-5d316a726462" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-70ce-be24-c6f911510072" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SeniorNotesDue2034Member_019fa40d-878f-7f79-9742-72d23d6e43a8" xlink:href="oii-20260930.xsd#oii_SeniorNotesDue2034Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-70ce-be24-c6f911510072" xlink:to="loc_oii_SeniorNotesDue2034Member_019fa40d-878f-7f79-9742-72d23d6e43a8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_019fa40d-878f-7ebf-9e25-1c36da9d8f34" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-70ce-be24-c6f911510072" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_019fa40d-878f-7ebf-9e25-1c36da9d8f34" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_RevolvingCreditFacilityApr2022Member_019fa40d-878f-7f85-8c41-ffd179ef2911" xlink:href="oii-20260930.xsd#oii_RevolvingCreditFacilityApr2022Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fa40d-878f-70ce-be24-c6f911510072" xlink:to="loc_oii_RevolvingCreditFacilityApr2022Member_019fa40d-878f-7f85-8c41-ffd179ef2911" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019fa40d-878f-7b32-968b-462ba6481082" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fa40d-878f-724c-bc44-13fec8121f55" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019fa40d-878f-7b32-968b-462ba6481082" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_019fa40d-878f-7465-abdb-9fe56c9ab33a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fa40d-878f-724c-bc44-13fec8121f55" xlink:to="loc_us-gaap_DebtInstrumentTerm_019fa40d-878f-7465-abdb-9fe56c9ab33a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019fa40d-878f-745c-9d72-00c886426c64" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fa40d-878f-724c-bc44-13fec8121f55" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019fa40d-878f-745c-9d72-00c886426c64" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_PercentageOfFederalFundsRate_019fa40d-878f-7242-8027-66fa86d23c9a" xlink:href="oii-20260930.xsd#oii_PercentageOfFederalFundsRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fa40d-878f-724c-bc44-13fec8121f55" xlink:to="loc_oii_PercentageOfFederalFundsRate_019fa40d-878f-7242-8027-66fa86d23c9a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_019fa40d-878f-700b-a3fa-0ded86442a6f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fa40d-878f-724c-bc44-13fec8121f55" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_019fa40d-878f-700b-a3fa-0ded86442a6f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets_019fa40d-878f-768d-87fc-8fdb90f18277" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fa40d-878f-724c-bc44-13fec8121f55" xlink:to="loc_us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets_019fa40d-878f-768d-87fc-8fdb90f18277" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BankingRegulationMaximumLeveragePayoutRatio_019fa40d-878f-77bc-8e0d-41524880d4d2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BankingRegulationMaximumLeveragePayoutRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fa40d-878f-724c-bc44-13fec8121f55" xlink:to="loc_us-gaap_BankingRegulationMaximumLeveragePayoutRatio_019fa40d-878f-77bc-8e0d-41524880d4d2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_MaximumPermittedLeverageRatio_019fa40d-878f-7c64-a1e2-61662ef46149" xlink:href="oii-20260930.xsd#oii_MaximumPermittedLeverageRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fa40d-878f-724c-bc44-13fec8121f55" xlink:to="loc_oii_MaximumPermittedLeverageRatio_019fa40d-878f-7c64-a1e2-61662ef46149" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_FutureMaximumLeverageRatio_019fa40d-878f-7429-8ea7-bde9e75fc6e0" xlink:href="oii-20260930.xsd#oii_FutureMaximumLeverageRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fa40d-878f-724c-bc44-13fec8121f55" xlink:to="loc_oii_FutureMaximumLeverageRatio_019fa40d-878f-7429-8ea7-bde9e75fc6e0" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_FederalFundsRate_019fa40d-878f-704e-a93f-222f61f66685" xlink:href="oii-20260930.xsd#oii_FederalFundsRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fa40d-878f-724c-bc44-13fec8121f55" xlink:to="loc_oii_FederalFundsRate_019fa40d-878f-704e-a93f-222f61f66685" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotes_019fa40d-878f-7f27-bcec-2fa5cc604bd8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorNotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fa40d-878f-724c-bc44-13fec8121f55" xlink:to="loc_us-gaap_SeniorNotes_019fa40d-878f-7f27-bcec-2fa5cc604bd8" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_DebtSublimit_019fa40d-878f-73da-b6d4-0975dc199a67" xlink:href="oii-20260930.xsd#oii_DebtSublimit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fa40d-878f-724c-bc44-13fec8121f55" xlink:to="loc_oii_DebtSublimit_019fa40d-878f-73da-b6d4-0975dc199a67" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRepurchasedFaceAmount_019fa40d-878f-7efb-9aeb-dd0c870db9a6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentRepurchasedFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fa40d-878f-724c-bc44-13fec8121f55" xlink:to="loc_us-gaap_DebtInstrumentRepurchasedFaceAmount_019fa40d-878f-7efb-9aeb-dd0c870db9a6" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_DebtInstrumentBaseRateLoanRates_019fa40d-878f-7be2-9783-81630e13e46c" xlink:href="oii-20260930.xsd#oii_DebtInstrumentBaseRateLoanRates"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fa40d-878f-724c-bc44-13fec8121f55" xlink:to="loc_oii_DebtInstrumentBaseRateLoanRates_019fa40d-878f-7be2-9783-81630e13e46c" xlink:type="arc" order="13"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.oceaneering.com/role/SegmentReportingDetails" xlink:type="simple" xlink:href="oii-20260930.xsd#SegmentReportingDetails"/>
  <link:definitionLink xlink:role="http://www.oceaneering.com/role/SegmentReportingDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019fa40d-878f-717f-82bc-1ce19add8c53" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019fa40d-878f-717f-82bc-1ce19add8c53" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-878f-7e24-a3a9-e28f1be1c94c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019fa40d-878f-717f-82bc-1ce19add8c53" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-878f-7e24-a3a9-e28f1be1c94c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-878f-7e24-a3a9-e28f1be1c94c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-878f-7e24-a3a9-e28f1be1c94c" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-878f-7e24-a3a9-e28f1be1c94c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fa40d-878f-7f5c-9233-d201a2c1c261" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fa40d-878f-7e24-a3a9-e28f1be1c94c" xlink:to="loc_us-gaap_SegmentDomain_019fa40d-878f-7f5c-9233-d201a2c1c261" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_SubseaRoboticsMemberMember_019fa40d-878f-7662-8723-89a2b8fe0d7e" xlink:href="oii-20260930.xsd#oii_SubseaRoboticsMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-7f5c-9233-d201a2c1c261" xlink:to="loc_oii_SubseaRoboticsMemberMember_019fa40d-878f-7662-8723-89a2b8fe0d7e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_ManufacturedProductsMemberMember_019fa40d-878f-7cdb-b727-dc34bfb255be" xlink:href="oii-20260930.xsd#oii_ManufacturedProductsMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-7f5c-9233-d201a2c1c261" xlink:to="loc_oii_ManufacturedProductsMemberMember_019fa40d-878f-7cdb-b727-dc34bfb255be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_IntegrityManagementsDigitalSolutionsMemberMember_019fa40d-878f-777f-bf0b-8ca274b01f08" xlink:href="oii-20260930.xsd#oii_IntegrityManagementsDigitalSolutionsMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-7f5c-9233-d201a2c1c261" xlink:to="loc_oii_IntegrityManagementsDigitalSolutionsMemberMember_019fa40d-878f-777f-bf0b-8ca274b01f08" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_OffshoreProjectsGroupMember_019fa40d-878f-7308-95dd-f8d25390bb47" xlink:href="oii-20260930.xsd#oii_OffshoreProjectsGroupMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-7f5c-9233-d201a2c1c261" xlink:to="loc_oii_OffshoreProjectsGroupMember_019fa40d-878f-7308-95dd-f8d25390bb47" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_AerospaceAndDefenseTechnologiesMemberMember_019fa40d-878f-7be8-9dfc-718926b5d650" xlink:href="oii-20260930.xsd#oii_AerospaceAndDefenseTechnologiesMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-7f5c-9233-d201a2c1c261" xlink:to="loc_oii_AerospaceAndDefenseTechnologiesMemberMember_019fa40d-878f-7be8-9dfc-718926b5d650" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_UnallocatedExpensesMember_019fa40d-878f-74ce-aef6-b3b4df2f0f7e" xlink:href="oii-20260930.xsd#oii_UnallocatedExpensesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-7f5c-9233-d201a2c1c261" xlink:to="loc_oii_UnallocatedExpensesMember_019fa40d-878f-74ce-aef6-b3b4df2f0f7e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_oii_AdvancedTechnologiesMember_019fa40d-878f-7aba-8665-8c198ba7ef01" xlink:href="oii-20260930.xsd#oii_AdvancedTechnologiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-7f5c-9233-d201a2c1c261" xlink:to="loc_oii_AdvancedTechnologiesMember_019fa40d-878f-7aba-8665-8c198ba7ef01" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateMember_019fa40d-878f-74dd-868d-d07adad91dbf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fa40d-878f-7f5c-9233-d201a2c1c261" xlink:to="loc_us-gaap_CorporateMember_019fa40d-878f-74dd-868d-d07adad91dbf" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019fa40d-878f-7ef1-819d-09c641307a0b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_Revenues_019fa40d-878f-7ef1-819d-09c641307a0b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_019fa40d-878f-71ed-b7c3-0772fcde7142" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_019fa40d-878f-71ed-b7c3-0772fcde7142" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019fa40d-878f-71a5-a811-26441a8f1171" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019fa40d-878f-71a5-a811-26441a8f1171" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_019fa40d-878f-7f1d-907c-fc4749a05b6e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Depreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_Depreciation_019fa40d-878f-7f1d-907c-fc4749a05b6e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_019fa40d-878f-70e8-81c6-4cf341c0da27" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_019fa40d-878f-70e8-81c6-4cf341c0da27" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_019fa40d-878f-74c0-8c22-1c41629ce785" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_019fa40d-878f-74c0-8c22-1c41629ce785" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentExpenditureAdditionToLongLivedAssets_019fa40d-8790-7b84-a0fb-946155e6d62a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentExpenditureAdditionToLongLivedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_SegmentExpenditureAdditionToLongLivedAssets_019fa40d-8790-7b84-a0fb-946155e6d62a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019fa40d-8790-7a09-b315-3c3b950c1a61" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_OperatingIncomeLoss_019fa40d-8790-7a09-b315-3c3b950c1a61" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_019fa40d-8790-73cf-bf4f-17422da22956" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_NumberOfReportableSegments_019fa40d-8790-73cf-bf4f-17422da22956" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossIncludingPortionAttributableToNoncontrollingInterest_019fa40d-8790-7f8c-9c82-23f6a84ba139" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_IncomeLossIncludingPortionAttributableToNoncontrollingInterest_019fa40d-8790-7f8c-9c82-23f6a84ba139" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInterest_019fa40d-8790-7b2e-96d2-f87ddd745a25" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentIncomeInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_InvestmentIncomeInterest_019fa40d-8790-7b2e-96d2-f87ddd745a25" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_019fa40d-8790-77cb-b586-956a3617ea1f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_InterestExpense_019fa40d-8790-77cb-b586-956a3617ea1f" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019fa40d-8790-7abc-8215-00fb573b0e8a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019fa40d-8790-7abc-8215-00fb573b0e8a" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019fa40d-8790-7bb0-9af8-40e1cf7c07db" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_019fa40d-8790-7bb0-9af8-40e1cf7c07db" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019fa40d-8790-7a47-828e-16e3cc40b10e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_Assets_019fa40d-8790-7a47-828e-16e3cc40b10e" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_019fa40d-8790-7014-b4d0-6b0d980ae514" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_019fa40d-8790-7014-b4d0-6b0d980ae514" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019fa40d-8790-7c47-a195-7fe3e3d37e47" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_Goodwill_019fa40d-8790-7c47-a195-7fe3e3d37e47" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentForAmortization_019fa40d-8790-7dcf-96c0-a75a4144c248" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentForAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_AdjustmentForAmortization_019fa40d-8790-7dcf-96c0-a75a4144c248" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_01a14b5f-bfc2-798f-b068-9a5058076e3d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fa40d-878f-7c77-ae43-45f69f0de745" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_01a14b5f-bfc2-798f-b068-9a5058076e3d" xlink:type="arc" order="18"/>
  </link:definitionLink>
</link:linkbase>
