v3.25.2

Warrants - Class of warrants (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2025	Jun. 30, 2025	Dec. 31, 2024
Class A Warrants
Warrants
Outstanding beginning		6,230,770	3,980,770
Issued			2,250,000
Exercised		(250,000)
Outstanding ending	5,980,770	5,980,770	6,230,770
Class of warrant exercised	1,638,270	1,638,270
Proceeds from warrants to be exercised	$ 3.6
Class B Warrants
Warrants
Outstanding beginning		7,450,000
Issued		2,500,000
Exercised	(6,335,000)	(6,335,000)
Outstanding ending	3,615,000	3,615,000	7,450,000
Class of warrant exercised through cashless		5,035,000
Class of warrants or right, shares issued on cashless exercise		3,533,096

- Definition

Number of warrants are exercised through cashless transaction.

+ References

No definition available.

+ Details

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

- Definition

Number of warrants or rights are exercised.

+ References

No definition available.

+ Details

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

- Definition

Number of shares issued for warrants exercised through cashless transaction.

+ References

No definition available.

+ Details

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

- Definition

The number of warrants issued during the period.

+ References

No definition available.

+ Details

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

- Definition

Represents the number of warrants or rights to be exercised.

+ References

No definition available.

+ Details

Name:	tmc_ClassOfWarrantsOrRightToBeExercised
Namespace Prefix:	tmc_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash inflow associated with the amount received from holders for warrants or right to be exercised.

+ References

No definition available.

+ Details

Name:	tmc_ProceedsFromWarrantOrRightToBeExercised
Namespace Prefix:	tmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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 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

- Details

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

- Details

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

TMC the metals Co Inc. 10-Q