<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2020-09-25</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001735707</issuerCik>
        <issuerName>Garrett Motion Inc.</issuerName>
        <issuerTradingSymbol>GTX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001166564</rptOwnerCik>
            <rptOwnerName>CYRUS CAPITAL PARTNERS, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>65 EAST 55TH STREET, 35TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001166774</rptOwnerCik>
            <rptOwnerName>CYRUS CAPITAL PARTNERS GP, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CYRUS CAPITAL PARTNERS, L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>65 EAST 55TH STREET, 35TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001251783</rptOwnerCik>
            <rptOwnerName>FREIDHEIM STEPHEN C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CYRUS CAPITAL PARTNERS, L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>65 EAST 55TH STREET, 35TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-09-25</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>514550</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.5578</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10220254</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">These shares of common stock, $0.001 par value per share (the &quot;Shares&quot;), of Garrett Motion Inc. are beneficially owned by (i) Cyrus Capital Partners, L.P. (&quot;Cyrus Capital Partners&quot;), as a result of being the investment manager of certain private investment funds that directly hold Shares, including Cyrus 1740 Master Fund, L.P., Canary SC Master Fund, L.P., Cyrus Opportunities Master Fund II, Ltd., Crescent 1, L.P., CRS Master Fund, L.P., Cyrus Select Opportunities Master Fund, Ltd., Cyrus Select Opportunities Master Fund II, L.P., PC Investors III LLC, and Peterson Capital Investors LLC, (ii) Cyrus Capital Partners GP, L.L.C. (&quot;Cyrus Capital GP&quot;), as a result of being the sole general partner of Cyrus Capital Partners, and (iii) Stephen C. Freidheim, as a result of being the Chief Investment Officer of Cyrus Capital Partners and the sole member and manager of Cyrus Capital GP.</footnote>
    </footnotes>

    <remarks>The Reporting Persons are jointly filing this Form 4.</remarks>

    <ownerSignature>
        <signatureName>STEPHEN C. FREIDHEIM  By: /s/ Stephen C. Freidheim</signatureName>
        <signatureDate>2020-10-06</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>CYRUS CAPITAL PARTNERS GP, L.L.C.  By: /s/ Stephen C. Freidheim, Stephen C. Freidheim its Sole Member/Manager</signatureName>
        <signatureDate>2020-10-06</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>CYRUS CAPITAL PARTNERS, L.P.  By: Cyrus Capital Partners GP, L.L.C., its general partner, By: /s/ Stephen C. Freidheim, Stephen C. Freidheim its Sole Member/Manager</signatureName>
        <signatureDate>2020-10-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
