Represents the warrants to acquire shares of common stock in business combination.

No definition available.

Name:	tmc_BusinessCombinationWarrantsToAcquireSharesOfCommonStock
Namespace Prefix:	tmc_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value of financial instrument classified as a liabilities measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

No definition available.

+ Details

Name:	tmc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringAndNonrecurringBasisLiabilityValue
Namespace Prefix:	tmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represent to Information of Settlement Of final Payment.

+ References

No definition available.

+ Details

Name:	tmc_SettlementOfFinalPayment
Namespace Prefix:	tmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The issuance price of additional capital which would trigger an adjustment in the exercise price of the warrant.

+ References

No definition available.

+ Details

Name:	tmc_WarrantExercisePriceAdjustmentTrigger
Namespace Prefix:	tmc_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of consecutive trading days within a specified range when the reported sale price must exceed the specified amount.

+ References

No definition available.

+ Details

Name:	tmc_WarrantRedemptionMeasurementConsecutiveTradingDaysOverSpecifiedAmount
Namespace Prefix:	tmc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of trading days over which the reported sale price is measured when determining the redemption price.

+ References

No definition available.

+ Details

Name:	tmc_WarrantRedemptionMeasurementPeriod
Namespace Prefix:	tmc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

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.

+ References

No definition available.

+ Details

Name:	us-gaap_ClassOfWarrantOrRightLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of securities into which each warrant or right may be converted. For example, but not limited to, each warrant may be converted into two shares.

+ References

No definition available.

+ Details

Name:	us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=126973232&loc=d3e21475-112644

+ Details

Name:	us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of warrants or rights outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_ClassOfWarrantOrRightOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Value of outstanding derivative securities that permit the holder the right to purchase securities (usually equity) from the issuer at a specified price.

+ References

No definition available.

+ Details

Name:	us-gaap_WarrantsAndRightsOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_BusinessAcquisitionAxis=tmc_PmtsAgreementAmendmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=us-gaap_PrivatePlacementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=tmc_PublicWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=tmc_SoacMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=us-gaap_IPOMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=tmc_RedemptionOfWarrantsWhenPricePerShareOfClassCommonStockEqualsOrExceeds18.00Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=tmc_PrivatePlacementWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=tmc_AllseasWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=tmc_PilotMiningTestSystemIsCompletedBySeptember302023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=tmc_PilotMiningTestSystemIsCompletedBySeptember302025Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Warrants (Details) $ / shares in Units, $ in Thousands		9 Months Ended
Warrants (Details) $ / shares in Units, $ in Thousands	Nov. 11, 2022 USD ($)	Sep. 30, 2022 USD ($) D $ / shares shares	Dec. 31, 2021 USD ($) shares
PMTS Agreement Amendment [Member] \| Subsequent event
Class of Warrant or Right:
Settlement Of final Payment \| $	$ 10,000
Private warrants
Class of Warrant or Right:
Fair value of outstanding recorded as warrants liability \| $		$ 2,234	$ 3,126
Public Warrants
Class of Warrant or Right:
Number of warrants outstanding		15,000,000	15,000,000
Outstanding Public Warrants \| $		$ 19,500
Public Warrants \| SOAC \| IPO [Member]
Class of Warrant or Right:
Warrants to acquire shares of common stock		15,000,000
Public Warrants \| Minimum
Class of Warrant or Right:
Trading days for redemption of public warrants \| D		20
Public Warrants \| Maximum [Member]
Class of Warrant or Right:
Consecutive trading days for redemption of public warrants \| D		30
Public Warrants \| Redemption Of Warrants When Price Per Share Of Class Common Stock Equals Or Exceeds 18.00
Class of Warrant or Right:
Issue price per share \| $ / shares		$ 18.00
Private Warrants
Class of Warrant or Right:
Number of warrants outstanding		9,500,000	9,500,000
Number of shares issuable per warrant		0
Private Warrants \| SOAC \| Private warrants
Class of Warrant or Right:
Warrants to acquire shares of common stock		9,500,000
Allseas Warrants \| PMTS Agreement Amendment [Member] \| Subsequent event
Class of Warrant or Right:
Settlement Of final Payment \| $	$ 11,600
Allseas Warrants \| PMTS is completed by September 30, 2023
Class of Warrant or Right:
Number of warrants purchased		11,600,000
Allseas Warrants \| PMTS is completed after September 30, 2025
Class of Warrant or Right:
Number of warrants purchased		5,800,000