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        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001798562</identifier>
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        <period>
            <startDate>2022-09-27</startDate>
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    <unit id="USD">
        <measure>iso4217:USD</measure>
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    <unit id="Shares">
        <measure>shares</measure>
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        <divide>
            <unitNumerator>
                <measure>iso4217:USD</measure>
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                <measure>shares</measure>
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    <dei:EntityCentralIndexKey contextRef="From2022-09-27to2022-09-27">0001798562</dei:EntityCentralIndexKey>
    <dei:AmendmentFlag contextRef="From2022-09-27to2022-09-27">true</dei:AmendmentFlag>
    <dei:EntityRegistrantName contextRef="From2022-09-27to2022-09-27" id="xdx2ixbrl0012">TMC the metals Co Inc.</dei:EntityRegistrantName>
    <dei:EntityTaxIdentificationNumber contextRef="From2022-09-27to2022-09-27" id="xdx2ixbrl0015">00-0000000</dei:EntityTaxIdentificationNumber>
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    <dei:Security12bTitle contextRef="From2022-09-272022-09-27_custom_RedeemablewarrantseachwholewarrantexercisableforoneTMCCommonShareeachatanexercisepriceofdollar1150pershareMember">Redeemable warrants, each whole warrant exercisable for one TMC Common Share, each at an exercise price of $11.50 per share</dei:Security12bTitle>
    <dei:TradingSymbol contextRef="From2022-09-272022-09-27_custom_RedeemablewarrantseachwholewarrantexercisableforoneTMCCommonShareeachatanexercisepriceofdollar1150pershareMember">TMCWW</dei:TradingSymbol>
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    <dei:EntityEmergingGrowthCompany contextRef="From2022-09-27to2022-09-27">true</dei:EntityEmergingGrowthCompany>
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    <dei:AmendmentDescription contextRef="From2022-09-27to2022-09-27">This current report on Form 8-K/A (the &#x201c;Amendment&#x201d;) amends
the current report on Form 8-K filed by TMC the metals company Inc. (the &#x201c;Company&#x201d;) with the U.S. Securities and Exchange
Commission on October 3, 2022 (the &#x201c;Original Form 8-K&#x201d;). The Original Form 8-K reported the appointment of Andrew C. Greig
to the Board of Directors of the Company (the &#x201c;Board&#x201d;), effective September 29, 2022, for a term to continue until the 2023
annual meeting of the Company&#x2019;s shareholders or until his earlier death, resignation or removal. At the time of the filing of the
Original Form 8-K, no determination had been made with respect to the appointment of Mr. Greig to any committees of the Board. This Amendment
is being filed solely to report that on November 10, 2022, upon the recommendation of the Nominating and Corporate Governance Committee
of the Board, the Board appointed Mr. Greig to the Compensation Committee of the Board, effective immediately, and Mr. Greig&#x2019;s appointment as Lead Independent Director on November 11, 2022. No other changes have been
made to the Original Form 8-K.</dei:AmendmentDescription>
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