v3.26.3
Cover
Sep. 23, 2026
Cover [Abstract]  
Document Type 8-K
Amendment Flag false
Document Period End Date Sep. 23, 2026
Entity File Number 001-39281
Entity Registrant Name TMC the metals Co Inc.
Entity Central Index Key 0001798562
Entity Tax Identification Number 00-0000000
Entity Incorporation, State or Country Code A1
Entity Address, Address Line One 1111 West Hastings Street
Entity Address, Address Line Two 15th Floor
Entity Address, City or Town Vancouver
Entity Address, State or Province BC
Entity Address, Postal Zip Code V6E 2J3
City Area Code 888
Local Phone Number 458-3420
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Title of 12(b) Security TMC Common Shares without par value
Trading Symbol TMC
Security Exchange Name NASDAQ
Entity Emerging Growth Company false