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

    <schemaVersion>X0407</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2023-04-17</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 SREET, 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 SREET, 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>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2023-04-17</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>110104</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>8.17</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9946538</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2023-04-18</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>74912</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.96</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9871626</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The price reported in column 4 is a weighted average price.  These shares were sold in multiple transactions at prces ranging from $8.05 to $8.335.</footnote>
        <footnote id="F2">The price reported in column 4 is a weighted average price.  These shares were sold in multiple transactions at prces ranging from $7.90 to $8.12.</footnote>
        <footnote id="F3">The securities reported herein 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 the securities, 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., PJ A Capital 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 (collectively, the &quot;Reporting Persons&quot;).</footnote>
        <footnote id="F4">(Continued from footnote 3) Each of the Reporting Persons disclaims beneficial ownership of any securities reported by any person except to the extent of their pecuniary interest therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>STEPHEN C. FREIDHEIM, By: /s/ Stephen C. Freidheim</signatureName>
        <signatureDate>2023-04-19</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>2023-04-19</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>2023-04-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
