{ "version": "2.2", "instance": { "tmc-20260928xex2d01.htm": { "nsprefix": "tmc", "nsuri": "http://tmcmetalscompany.com/20260928", "dts": { "schema": { "local": [ "tmc-20260928.xsd" ], "remote": [ "http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd", "http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd", "http://www.xbrl.org/2003/xl-2003-12-31.xsd", "http://www.xbrl.org/2003/xlink-2003-12-31.xsd", "http://www.xbrl.org/2005/xbrldt-2005.xsd", "http://www.xbrl.org/2014/extensible-enumerations.xsd", "http://www.xbrl.org/lrr/arcrole/esma-arcrole-2018-11-21.xsd", "https://www.xbrl.org/dtr/type/2020-01-21/types.xsd", "https://www.xbrl.org/dtr/type/2024-01-31/types.xsd", "https://xbrl.sec.gov/country/2026/country-2026.xsd", "https://xbrl.sec.gov/country/2026/country-2026_def.xsd", "https://xbrl.sec.gov/dei/2026/dei-2026.xsd", "https://xbrl.sec.gov/rxp/2026/rxp-2026.xsd", "https://xbrl.sec.gov/snj/2026/snj-2026.xsd", "https://xbrl.sec.gov/snj/2026/snj-2026_def.xsd" ] }, "inline": { "local": [ "tmc-20260928xex2d01.htm" ] } }, "keyStandard": 21, "keyCustom": 0, "axisStandard": 4, "axisCustom": 0, "memberStandard": 4, "memberCustom": 8, "hidden": { "total": 79, "http://xbrl.sec.gov/rxp/2026": 75, "http://xbrl.sec.gov/dei/2026": 4 }, "contextCount": 17, "entityCount": 1, "segmentCount": 12, "elementCount": 57, "unitCount": 1, "baseTaxonomies": { "http://xbrl.sec.gov/rxp/2026": 98, "http://xbrl.sec.gov/dei/2026": 6 }, "report": { "R1": { "role": "http://xbrl.sec.gov/dei/role/document/DocumentInformation", "longName": "995200 - Document - Document Information", "shortName": "Document Information", "isDefault": "true", "groupType": "document", "subGroupType": "", "menuCat": "Cover", "order": "1", "firstAnchor": { "contextRef": "Duration_1_1_2025_To_12_31_2025_ZnGJpGFevUypHh5x2sHhiw", "name": "dei:DocumentPeriodEndDate", "unitRef": null, "xsiNil": "false", "lang": "en-US", "decimals": null, "ancestors": [ "p", "div", "div", "body", "html" ], "reportCount": 1, "baseRef": "tmc-20260928xex2d01.htm", "first": true, "unique": true }, "uniqueAnchor": { "contextRef": "Duration_1_1_2025_To_12_31_2025_ZnGJpGFevUypHh5x2sHhiw", "name": "dei:DocumentPeriodEndDate", "unitRef": null, "xsiNil": "false", "lang": "en-US", "decimals": null, "ancestors": [ "p", "div", "div", "body", "html" ], "reportCount": 1, "baseRef": "tmc-20260928xex2d01.htm", "first": true, "unique": true } }, "R2": { "role": "http://xbrl.sec.gov/rxp/role/ByProject", "longName": "995601 - Disclosure - Payments, by Project", "shortName": "Payments, by Project", "isDefault": "false", "groupType": "disclosure", "subGroupType": "", "menuCat": "Notes", "order": "2", "firstAnchor": { "contextRef": "Duration_1_1_2025_To_12_31_2025_rxp_ProjectAxis_tmc_NauruOceanResourcesIncProjectMember_CSFRhLW27UOM0eK2rSBQRw", "name": "rxp:Fees", "unitRef": "Unit_Standard_USD_ReQIodXZzEyiG3C_mn-dUg", "xsiNil": "false", "lang": null, "decimals": "-3", "ancestors": [ "p", "td", "tr", "table", "div", "div", "body", "html" ], "reportCount": 1, "baseRef": "tmc-20260928xex2d01.htm", "first": true, "unique": true }, "uniqueAnchor": { "contextRef": "Duration_1_1_2025_To_12_31_2025_rxp_ProjectAxis_tmc_NauruOceanResourcesIncProjectMember_CSFRhLW27UOM0eK2rSBQRw", "name": "rxp:Fees", "unitRef": "Unit_Standard_USD_ReQIodXZzEyiG3C_mn-dUg", "xsiNil": "false", "lang": null, "decimals": "-3", "ancestors": [ "p", "td", "tr", "table", "div", "div", "body", "html" ], "reportCount": 1, "baseRef": "tmc-20260928xex2d01.htm", "first": true, "unique": true } }, "R3": { "role": "http://xbrl.sec.gov/rxp/role/ByGovernment", "longName": "995602 - Disclosure - Payments, by Government", "shortName": "Payments, by Government", "isDefault": "false", "groupType": "disclosure", "subGroupType": "", "menuCat": "Notes", "order": "3", "firstAnchor": { "contextRef": "Duration_1_1_2025_To_12_31_2025_rxp_CountryAxis_country_NR_rxp_GovernmentAxis_tmc_RepublicOfNaoeroNaoeroSeabedMineralsAuthorityMember_-qKYCMlIM0STQvlW7XcYwQ", "name": "rxp:Fees", "unitRef": "Unit_Standard_USD_ReQIodXZzEyiG3C_mn-dUg", "xsiNil": "false", "lang": null, "decimals": "-3", "ancestors": [ "p", "td", "tr", "table", "div", "div", "body", "html" ], "reportCount": 1, "baseRef": "tmc-20260928xex2d01.htm", "first": true, "unique": true }, "uniqueAnchor": { "contextRef": "Duration_1_1_2025_To_12_31_2025_rxp_CountryAxis_country_NR_rxp_GovernmentAxis_tmc_RepublicOfNaoeroNaoeroSeabedMineralsAuthorityMember_-qKYCMlIM0STQvlW7XcYwQ", "name": "rxp:Fees", "unitRef": "Unit_Standard_USD_ReQIodXZzEyiG3C_mn-dUg", "xsiNil": "false", "lang": null, "decimals": "-3", "ancestors": [ "p", "td", "tr", "table", "div", "div", "body", "html" ], "reportCount": 1, "baseRef": "tmc-20260928xex2d01.htm", "first": true, "unique": true } }, "R4": { "role": "http://xbrl.sec.gov/rxp/role/Detail", "longName": "995603 - Disclosure - Payments, Details", "shortName": "Payments, Details", "isDefault": "false", "groupType": "disclosure", "subGroupType": "", "menuCat": "Notes", "order": "4", "firstAnchor": null, "uniqueAnchor": null } }, "tag": { "rxp_A": { "xbrltype": "monetaryItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "A", "crdr": "debit", "presentation": [ "http://xbrl.sec.gov/rxp/role/Detail" ], "lang": { "en-us": { "role": { "label": "Amount", "terseLabel": "Amount" } } }, "auth_ref": [ "r1" ] }, "country_AllCountriesDomain": { "xbrltype": "domainItemType", "nsuri": "http://xbrl.sec.gov/country/2026", "localname": "AllCountriesDomain", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByGovernment" ], "lang": { "en-us": { "role": { "label": "All Countries [Domain]", "terseLabel": "All Countries" } } }, "auth_ref": [] }, "rxp_AllGovernmentsMember": { "xbrltype": "domainItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "AllGovernmentsMember", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByGovernment" ], "lang": { "en-us": { "role": { "label": "All Governments [Member]", "terseLabel": "All Governments" } } }, "auth_ref": [ "r12", "r13" ] }, "rxp_AllProjectsMember": { "xbrltype": "domainItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "AllProjectsMember", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByProject" ], "lang": { "en-us": { "role": { "label": "All Projects [Member]", "terseLabel": "All Projects" } } }, "auth_ref": [ "r11" ] }, "rxp_AlternativeReportingRegime": { "xbrltype": "alternativeReportingRegimeItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "AlternativeReportingRegime", "presentation": [ "http://xbrl.sec.gov/dei/role/document/DocumentInformation" ], "lang": { "en-us": { "role": { "label": "Alternative Reporting Regime", "terseLabel": "Alternative Reporting Regime" } } }, "auth_ref": [ "r10" ] }, "dei_AmendmentDescription": { "xbrltype": "stringItemType", "nsuri": "http://xbrl.sec.gov/dei/2026", "localname": "AmendmentDescription", "presentation": [ "http://xbrl.sec.gov/dei/role/document/DocumentInformation" ], "lang": { "en-us": { "role": { "label": "Amendment Description", "terseLabel": "Amendment Description", "documentation": "Description of changes contained within amended document." } } }, "auth_ref": [] }, "dei_AmendmentFlag": { "xbrltype": "booleanItemType", "nsuri": "http://xbrl.sec.gov/dei/2026", "localname": "AmendmentFlag", "presentation": [ "http://xbrl.sec.gov/dei/role/document/DocumentInformation" ], "lang": { "en-us": { "role": { "label": "Amendment Flag", "terseLabel": "Amendment", "documentation": "Boolean flag that is true when the XBRL content amends previously-filed or accepted submission." } } }, "auth_ref": [] }, "rxp_Bonuses": { "xbrltype": "monetaryItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "Bonuses", "crdr": "debit", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByCategory", "http://xbrl.sec.gov/rxp/role/ByGovernment", "http://xbrl.sec.gov/rxp/role/ByProject" ], "lang": { "en-us": { "role": { "label": "Bonuses", "terseLabel": "Bonuses" } } }, "auth_ref": [ "r19" ] }, "rxp_Cm": { "xbrltype": "conversionMethodItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "Cm", "presentation": [ "http://xbrl.sec.gov/rxp/role/Detail" ], "lang": { "en-us": { "role": { "label": "Currency Conversion Method", "terseLabel": "Curr. Conv. Method" } } }, "auth_ref": [ "r24" ] }, "rxp_Co": { "xbrltype": "enumerationItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "Co", "presentation": [ "http://xbrl.sec.gov/rxp/role/Detail" ], "lang": { "en-us": { "role": { "label": "Country", "terseLabel": "Country" } } }, "auth_ref": [ "r6" ] }, "rxp_CommunityAndSocial": { "xbrltype": "monetaryItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "CommunityAndSocial", "crdr": "debit", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByCategory", "http://xbrl.sec.gov/rxp/role/ByGovernment", "http://xbrl.sec.gov/rxp/role/ByProject" ], "lang": { "en-us": { "role": { "label": "Community and Social Responsibility", "terseLabel": "Comm. Social Resp." } } }, "auth_ref": [ "r22" ] }, "rxp_CountryAxis": { "xbrltype": "stringItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "CountryAxis", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByGovernment" ], "lang": { "en-us": { "role": { "label": "Country [Axis]", "terseLabel": "Country:" } } }, "auth_ref": [ "r25" ] }, "dei_CoverAbstract": { "xbrltype": "stringItemType", "nsuri": "http://xbrl.sec.gov/dei/2026", "localname": "CoverAbstract", "lang": { "en-us": { "role": { "label": "Cover [Abstract]", "terseLabel": "Cover", "documentation": "Cover page." } } }, "auth_ref": [] }, "rxp_Dividends": { "xbrltype": "monetaryItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "Dividends", "crdr": "debit", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByCategory", "http://xbrl.sec.gov/rxp/role/ByGovernment", "http://xbrl.sec.gov/rxp/role/ByProject" ], "lang": { "en-us": { "role": { "label": "Dividends", "terseLabel": "Dividends" } } }, "auth_ref": [ "r20" ] }, "dei_DocumentInformationLineItems": { "xbrltype": "stringItemType", "nsuri": "http://xbrl.sec.gov/dei/2026", "localname": "DocumentInformationLineItems", "presentation": [ "http://xbrl.sec.gov/dei/role/document/DocumentInformation" ], "lang": { "en-us": { "role": { "label": "Document Information [Line Items]", "terseLabel": "Document Information:", "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table." } } }, "auth_ref": [] }, "dei_DocumentInformationTable": { "xbrltype": "stringItemType", "nsuri": "http://xbrl.sec.gov/dei/2026", "localname": "DocumentInformationTable", "presentation": [ "http://xbrl.sec.gov/dei/role/document/DocumentInformation" ], "lang": { "en-us": { "role": { "label": "Document Information [Table]", "terseLabel": "Document Information", "documentation": "Container to support the formal attachment of each official or unofficial, public or private document as part of a submission package." } } }, "auth_ref": [] }, "dei_DocumentPeriodEndDate": { "xbrltype": "dateItemType", "nsuri": "http://xbrl.sec.gov/dei/2026", "localname": "DocumentPeriodEndDate", "presentation": [ "http://xbrl.sec.gov/dei/role/document/DocumentInformation" ], "lang": { "en-us": { "role": { "label": "Document Period End Date", "terseLabel": "Period End Date", "documentation": "For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD." } } }, "auth_ref": [] }, "dei_DocumentType": { "xbrltype": "submissionTypeItemType", "nsuri": "http://xbrl.sec.gov/dei/2026", "localname": "DocumentType", "presentation": [ "http://xbrl.sec.gov/dei/role/document/DocumentInformation" ], "lang": { "en-us": { "role": { "label": "Document Type", "terseLabel": "Document Type", "documentation": "The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'." } } }, "auth_ref": [] }, "dei_EntityCentralIndexKey": { "xbrltype": "centralIndexKeyItemType", "nsuri": "http://xbrl.sec.gov/dei/2026", "localname": "EntityCentralIndexKey", "presentation": [ "http://xbrl.sec.gov/dei/role/document/DocumentInformation" ], "lang": { "en-us": { "role": { "label": "Entity Central Index Key", "terseLabel": "CIK", "documentation": "A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK." } } }, "auth_ref": [ "r0" ] }, "dei_EntityDomain": { "xbrltype": "domainItemType", "nsuri": "http://xbrl.sec.gov/dei/2026", "localname": "EntityDomain", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByCategory", "http://xbrl.sec.gov/rxp/role/ByGovernment", "http://xbrl.sec.gov/rxp/role/ByProject", "http://xbrl.sec.gov/rxp/role/Detail" ], "lang": { "en-us": { "role": { "label": "All Entities [Member]", "terseLabel": "All Entities", "documentation": "All the names of the entities being reported upon in a document. Any legal structure used to conduct activities or to hold assets. Some examples of such structures are corporations, partnerships, limited liability companies, grantor trusts, and other trusts. This item does not include business and geographical segments which are included in the geographical or business segments domains." } } }, "auth_ref": [] }, "dei_EntityRegistrantName": { "xbrltype": "normalizedStringItemType", "nsuri": "http://xbrl.sec.gov/dei/2026", "localname": "EntityRegistrantName", "presentation": [ "http://xbrl.sec.gov/dei/role/document/DocumentInformation" ], "lang": { "en-us": { "role": { "label": "Entity Registrant Name", "terseLabel": "Registrant Name", "documentation": "The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC." } } }, "auth_ref": [ "r0" ] }, "dei_EntityReportingCurrencyISOCode": { "xbrltype": "currencyItemType", "nsuri": "http://xbrl.sec.gov/dei/2026", "localname": "EntityReportingCurrencyISOCode", "presentation": [ "http://xbrl.sec.gov/dei/role/document/DocumentInformation" ], "lang": { "en-us": { "role": { "label": "Entity Reporting Currency ISO Code", "terseLabel": "Reporting Currency", "documentation": "The three character ISO 4217 code for the currency used for reporting purposes. Example: 'USD'." } } }, "auth_ref": [] }, "rxp_Fees": { "xbrltype": "monetaryItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "Fees", "crdr": "debit", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByCategory", "http://xbrl.sec.gov/rxp/role/ByGovernment", "http://xbrl.sec.gov/rxp/role/ByProject" ], "lang": { "en-us": { "role": { "label": "Fees", "terseLabel": "Fees" } } }, "auth_ref": [ "r17" ] }, "rxp_GovernmentAxis": { "xbrltype": "stringItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "GovernmentAxis", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByGovernment" ], "lang": { "en-us": { "role": { "label": "Government [Axis]", "terseLabel": "Government:" } } }, "auth_ref": [ "r12", "r13" ] }, "rxp_Gv": { "xbrltype": "enumerationItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "Gv", "presentation": [ "http://xbrl.sec.gov/rxp/role/Detail" ], "lang": { "en-us": { "role": { "label": "Government", "terseLabel": "Govt." } } }, "auth_ref": [ "r6" ] }, "rxp_InfrastructureImprovements": { "xbrltype": "monetaryItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "InfrastructureImprovements", "crdr": "debit", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByCategory", "http://xbrl.sec.gov/rxp/role/ByGovernment", "http://xbrl.sec.gov/rxp/role/ByProject" ], "lang": { "en-us": { "role": { "label": "Infrastructure Improvements", "terseLabel": "Infrastructure" } } }, "auth_ref": [ "r21" ] }, "rxp_K": { "xbrltype": "yesItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "K", "presentation": [ "http://xbrl.sec.gov/rxp/role/Detail" ], "lang": { "en-us": { "role": { "label": "In-kind", "terseLabel": "In-kind" } } }, "auth_ref": [ "r23" ] }, "tmc_KingdomOfTongaMinistryOfLandsAndNaturalResourcesMember": { "xbrltype": "domainItemType", "nsuri": "http://tmcmetalscompany.com/20260928", "localname": "KingdomOfTongaMinistryOfLandsAndNaturalResourcesMember", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByGovernment" ], "lang": { "en-us": { "role": { "documentation": "Represents the Kingdom of Tonga, Ministry of Lands and Natural Resources.", "label": "Kingdom of Tonga, Ministry of Lands and Natural Resources [Member]", "terseLabel": "Kingdom of Tonga, Ministry of Lands and Natural Resources" } } }, "auth_ref": [] }, "tmc_KingdomOfTongaTongaSeabedMineralsAuthorityMember": { "xbrltype": "domainItemType", "nsuri": "http://tmcmetalscompany.com/20260928", "localname": "KingdomOfTongaTongaSeabedMineralsAuthorityMember", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByGovernment" ], "lang": { "en-us": { "role": { "documentation": "Represents the Kingdom of Tonga, Tonga Seabed Minerals Authority.", "label": "Kingdom of Tonga, Tonga Seabed Minerals Authority [Member]", "terseLabel": "Kingdom of Tonga, Tonga Seabed Minerals Authority" } } }, "auth_ref": [] }, "rxp_Km": { "xbrltype": "stringItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "Km", "presentation": [ "http://xbrl.sec.gov/rxp/role/Detail" ], "lang": { "en-us": { "role": { "label": "In-kind Value Calculation", "terseLabel": "In-kind Calc." } } }, "auth_ref": [ "r23" ] }, "dei_LegalEntityAxis": { "xbrltype": "stringItemType", "nsuri": "http://xbrl.sec.gov/dei/2026", "localname": "LegalEntityAxis", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByCategory", "http://xbrl.sec.gov/rxp/role/ByGovernment", "http://xbrl.sec.gov/rxp/role/ByProject", "http://xbrl.sec.gov/rxp/role/Detail" ], "lang": { "en-us": { "role": { "label": "Legal Entity [Axis]", "terseLabel": "Legal Entity:", "documentation": "The set of legal entities associated with a report." } } }, "auth_ref": [] }, "rxp_M": { "xbrltype": "extractionMethodItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "M", "presentation": [ "http://xbrl.sec.gov/rxp/role/Detail" ], "lang": { "en-us": { "role": { "label": "Extraction Method", "terseLabel": "Ext. Method" } } }, "auth_ref": [ "r8" ] }, "country_NR": { "xbrltype": "domainItemType", "nsuri": "http://xbrl.sec.gov/country/2026", "localname": "NR", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByGovernment" ], "lang": { "en-us": { "role": { "label": "NAURU", "terseLabel": "Naoero" } } }, "auth_ref": [] }, "tmc_NationalOceanicAndAtmosphericAdministrationNoaaMember": { "xbrltype": "domainItemType", "nsuri": "http://tmcmetalscompany.com/20260928", "localname": "NationalOceanicAndAtmosphericAdministrationNoaaMember", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByGovernment" ], "lang": { "en-us": { "role": { "documentation": "Represents the National Oceanic and Atmospheric Administration (\"NOAA\").", "label": "National Oceanic and Atmospheric Administration (NOAA) [Member]", "terseLabel": "National Oceanic and Atmospheric Administration (\"NOAA\")" } } }, "auth_ref": [] }, "tmc_NauruOceanResourcesIncProjectMember": { "xbrltype": "domainItemType", "nsuri": "http://tmcmetalscompany.com/20260928", "localname": "NauruOceanResourcesIncProjectMember", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByProject" ], "lang": { "en-us": { "role": { "documentation": "Represents the NORI project relates to all payments to the Government of Naoero (formerly Nauru), including the Naoero Seabed Minerals Authority.", "label": "Nauru Ocean Resources Inc Project [Member]", "terseLabel": "NORI Project" } } }, "auth_ref": [] }, "rxp_P": { "xbrltype": "enumerationItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "P", "presentation": [ "http://xbrl.sec.gov/rxp/role/Detail" ], "lang": { "en-us": { "role": { "label": "Payment Type", "terseLabel": "Type" } } }, "auth_ref": [ "r1" ] }, "rxp_PaymentsByCategoryTable": { "xbrltype": "stringItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "PaymentsByCategoryTable", "lang": { "en-us": { "role": { "label": "Payments by Category [Table]", "terseLabel": "Payments:" } } }, "auth_ref": [ "r3" ] }, "rxp_PaymentsByGovernmentTable": { "xbrltype": "stringItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "PaymentsByGovernmentTable", "lang": { "en-us": { "role": { "label": "Payments by Government [Table]", "terseLabel": "Payments, by Government:" } } }, "auth_ref": [ "r2" ] }, "rxp_PaymentsByProjectTable": { "xbrltype": "stringItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "PaymentsByProjectTable", "lang": { "en-us": { "role": { "label": "Payments by Project [Table]", "terseLabel": "Payments, by Project:" } } }, "auth_ref": [ "r1" ] }, "rxp_PaymentsDetailTable": { "xbrltype": "stringItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "PaymentsDetailTable", "lang": { "en-us": { "role": { "label": "Payments Detail [Table]", "terseLabel": "Payments Detail:" } } }, "auth_ref": [ "r1" ] }, "rxp_PaymentsLineItems": { "xbrltype": "stringItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "PaymentsLineItems", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByCategory", "http://xbrl.sec.gov/rxp/role/ByGovernment", "http://xbrl.sec.gov/rxp/role/ByProject", "http://xbrl.sec.gov/rxp/role/Detail" ], "lang": { "en-us": { "role": { "label": "Payments [Line Items]", "terseLabel": "Payments:" } } }, "auth_ref": [ "r1" ] }, "rxp_PmtAxis": { "xbrltype": "stringItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "PmtAxis", "presentation": [ "http://xbrl.sec.gov/rxp/role/Detail" ], "lang": { "en-us": { "role": { "label": "Pmt [Axis]", "terseLabel": "#" } } }, "auth_ref": [ "r14" ] }, "rxp_Pr": { "xbrltype": "enumerationItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "Pr", "presentation": [ "http://xbrl.sec.gov/rxp/role/Detail" ], "lang": { "en-us": { "role": { "label": "Project", "terseLabel": "Project" } } }, "auth_ref": [ "r7" ] }, "rxp_ProductionEntitlements": { "xbrltype": "monetaryItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "ProductionEntitlements", "crdr": "debit", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByCategory", "http://xbrl.sec.gov/rxp/role/ByGovernment", "http://xbrl.sec.gov/rxp/role/ByProject" ], "lang": { "en-us": { "role": { "label": "Production Entitlements", "terseLabel": "Prod. Entitlements" } } }, "auth_ref": [ "r18" ] }, "rxp_ProjectAxis": { "xbrltype": "stringItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "ProjectAxis", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByProject" ], "lang": { "en-us": { "role": { "label": "Project [Axis]", "terseLabel": "Project:" } } }, "auth_ref": [ "r11" ] }, "rxp_R": { "xbrltype": "enumerationItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "R", "presentation": [ "http://xbrl.sec.gov/rxp/role/Detail" ], "lang": { "en-us": { "role": { "label": "Resource", "terseLabel": "Resource" } } }, "auth_ref": [ "r4" ] }, "tmc_RepublicOfNaoeroNaoeroSeabedMineralsAuthorityMember": { "xbrltype": "domainItemType", "nsuri": "http://tmcmetalscompany.com/20260928", "localname": "RepublicOfNaoeroNaoeroSeabedMineralsAuthorityMember", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByGovernment" ], "lang": { "en-us": { "role": { "documentation": "Represents the Republic of Naoero, Naoero Seabed Minerals Authority.", "label": "Republic of Naoero, Naoero Seabed Minerals Authority [Member]", "terseLabel": "Republic of Naoero, Naoero Seabed Minerals Authority" } } }, "auth_ref": [] }, "rxp_Royalties": { "xbrltype": "monetaryItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "Royalties", "crdr": "debit", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByCategory", "http://xbrl.sec.gov/rxp/role/ByGovernment", "http://xbrl.sec.gov/rxp/role/ByProject" ], "lang": { "en-us": { "role": { "label": "Royalties", "terseLabel": "Royalties" } } }, "auth_ref": [ "r16" ] }, "rxp_Sg": { "xbrltype": "enumerationItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "Sg", "presentation": [ "http://xbrl.sec.gov/rxp/role/Detail" ], "lang": { "en-us": { "role": { "label": "Segment", "terseLabel": "Segment" } } }, "auth_ref": [ "r5" ] }, "rxp_Sn": { "xbrltype": "enumerationItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "Sn", "presentation": [ "http://xbrl.sec.gov/rxp/role/Detail" ], "lang": { "en-us": { "role": { "label": "Subnational Jurisdiction", "terseLabel": "Subnat. Juris." } } }, "auth_ref": [ "r9" ] }, "country_TO": { "xbrltype": "domainItemType", "nsuri": "http://xbrl.sec.gov/country/2026", "localname": "TO", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByGovernment" ], "lang": { "en-us": { "role": { "label": "TONGA", "terseLabel": "Tonga" } } }, "auth_ref": [] }, "rxp_Taxes": { "xbrltype": "monetaryItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "Taxes", "crdr": "debit", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByCategory", "http://xbrl.sec.gov/rxp/role/ByGovernment", "http://xbrl.sec.gov/rxp/role/ByProject" ], "lang": { "en-us": { "role": { "label": "Taxes", "terseLabel": "Taxes" } } }, "auth_ref": [ "r15" ] }, "tmc_ThemetalsCompanyUsaLlcaProjectMember": { "xbrltype": "domainItemType", "nsuri": "http://tmcmetalscompany.com/20260928", "localname": "ThemetalsCompanyUsaLlcaProjectMember", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByProject" ], "lang": { "en-us": { "role": { "documentation": "Represents the project of our wholly owned subsidiary Tonga Offshore Mining Limited (\"TOML\") relates to all payments to the Government of Tonga, including the Tonga Seabed Minerals Authority and the Ministry of Lands and Natural Resources", "label": "TheMetals Company USA, LLCA Project [Member]", "terseLabel": "TMC USA-A" } } }, "auth_ref": [] }, "tmc_ThemetalsCompanyUsaLlcbProjectMember": { "xbrltype": "domainItemType", "nsuri": "http://tmcmetalscompany.com/20260928", "localname": "ThemetalsCompanyUsaLlcbProjectMember", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByProject" ], "lang": { "en-us": { "role": { "documentation": "Represents the TMC USA-B project relates to NOAA application fees paid by TMC USA for its DSHMRA application for an exploration license covering the TMC USA-B area of the CCZ.", "label": "TheMetals Company USA, LLCB Project [Member]", "terseLabel": "TMC USA-B" } } }, "auth_ref": [] }, "tmc_TongaOffshoreMiningLimitedProjectMember": { "xbrltype": "domainItemType", "nsuri": "http://tmcmetalscompany.com/20260928", "localname": "TongaOffshoreMiningLimitedProjectMember", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByProject" ], "lang": { "en-us": { "role": { "documentation": "Represents the project of our wholly owned subsidiary Tonga Offshore Mining Limited (\"TOML\") relates to all payments to the Government of Tonga, including the Tonga Seabed Minerals Authority and the Ministry of Lands and Natural Resources", "label": "Tonga Offshore Mining Limited Project [Member]", "terseLabel": "TOML Project" } } }, "auth_ref": [] }, "rxp_TotalPayments": { "xbrltype": "monetaryItemType", "nsuri": "http://xbrl.sec.gov/rxp/2026", "localname": "TotalPayments", "crdr": "debit", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByCategory", "http://xbrl.sec.gov/rxp/role/ByGovernment", "http://xbrl.sec.gov/rxp/role/ByProject" ], "lang": { "en-us": { "role": { "label": "Total Payments", "terseLabel": "Total Payments" } } }, "auth_ref": [ "r14" ] }, "country_US": { "xbrltype": "domainItemType", "nsuri": "http://xbrl.sec.gov/country/2026", "localname": "US", "presentation": [ "http://xbrl.sec.gov/rxp/role/ByGovernment" ], "lang": { "en-us": { "role": { "label": "UNITED STATES", "terseLabel": "United States" } } }, "auth_ref": [] } } } }, "std_ref": { "r0": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Exchange Act", "Number": "240", "Section": "12", "Subsection": "b-2" }, "r1": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "a", "Paragraph": "5" }, "r2": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "a", "Paragraph": "5", "Subparagraph": "ii" }, "r3": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "a", "Paragraph": "5", "Subparagraph": "iii" }, "r4": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "a", "Paragraph": "5", "Subparagraph": "ix" }, "r5": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "a", "Paragraph": "5", "Subparagraph": "vi" }, "r6": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "a", "Paragraph": "5", "Subparagraph": "vii" }, "r7": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "a", "Paragraph": "5", "Subparagraph": "viii" }, "r8": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "a", "Paragraph": "5", "Subparagraph": "x" }, "r9": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "a", "Paragraph": "5", "Subparagraph": "xi" }, "r10": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "c" }, "r11": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "d", "Paragraph": "10" }, "r12": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "d", "Paragraph": "6" }, "r13": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "d", "Paragraph": "7" }, "r14": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "d", "Paragraph": "9" }, "r15": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "d", "Paragraph": "9", "Subparagraph": "iii", "Clause": "A" }, "r16": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "d", "Paragraph": "9", "Subparagraph": "iii", "Clause": "B" }, "r17": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "d", "Paragraph": "9", "Subparagraph": "iii", "Clause": "C" }, "r18": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "d", "Paragraph": "9", "Subparagraph": "iii", "Clause": "D" }, "r19": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "d", "Paragraph": "9", "Subparagraph": "iii", "Clause": "E" }, "r20": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "d", "Paragraph": "9", "Subparagraph": "iii", "Clause": "F" }, "r21": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "d", "Paragraph": "9", "Subparagraph": "iii", "Clause": "G" }, "r22": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "d", "Paragraph": "9", "Subparagraph": "iii", "Clause": "H" }, "r23": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "instruction", "Paragraph": "12" }, "r24": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "instruction", "Paragraph": "2" }, "r25": { "role": "http://www.xbrl.org/2003/role/presentationRef", "Publisher": "SEC", "Name": "Form SD", "Section": "2.01", "Subsection": "instruction", "Paragraph": "3", "Subparagraph": "iii" } } }