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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-04-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000773840</rptOwnerCik>
            <rptOwnerName>HONEYWELL INTERNATIONAL INC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>300 SOUTH TRYON STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHARLOTTE</rptOwnerCity>
            <rptOwnerState>NC</rptOwnerState>
            <rptOwnerZipCode>28202</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>May be a member of 10% group</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-04-30</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2896116</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On September 20, 2020, Garrett Motion Inc. (the &quot;Issuer&quot;) and certain of its subsidiaries (collectively, the &quot;Debtors&quot;) each filed voluntary petitions (the &quot;Chapter 11 Cases&quot;) under chapter 11 of title 11 of the United States Code (the &quot;Bankruptcy Code&quot;) in the United States Bankruptcy Court for the Southern District of New York (the &quot;Bankruptcy Court&quot;). On April 26, 2021, the Debtors filed an amended Chapter 11 plan of reorganization (the &quot;Plan&quot;) and on April 9, 2021, the Issuer filed a supplement to the Plan (as amended on April 20, 2021 and April 22, 2021) with the Bankruptcy Court. On April 26, 2021, the Bankruptcy Court entered an order (the &quot;Confirmation Order&quot;) among other things, confirming the Plan, and on April 30, 2021 (the &quot;Effective Date&quot;),</footnote>
        <footnote id="F2">(Continued from footnote 1) the conditions to effectiveness of the Plan were satisfied or waived and the Debtors emerged from bankruptcy. On the Effective Date, and in accordance with the Plan and Confirmation Order, all shares of the Issuer's common stock, par value $0.001 per share, issued and outstanding immediately prior to the Effective Date (the &quot;Existing Common Stock&quot;), and any rights of any holder in respect thereof, were deemed cancelled, discharged and of no further force or effect. Accordingly, all the 2,896,116 shares of Existing Common Stock that Honeywell International Inc. (the &quot;Reporting Person&quot;) owned in the Company were cancelled.</footnote>
    </footnotes>

    <remarks>This filing constitutes a Form 4 exit filing for the Reporting Person, as the Reporting Person is no longer subject to Section 16 of the Securities Exchange Act of 1934, as amended, with respect to the Existing Common Stock as a result of the events reported herein.</remarks>

    <ownerSignature>
        <signatureName>/s/ Anna T. Madden, Senior Vice President and General Counsel of Honeywell International Inc.</signatureName>
        <signatureDate>2021-05-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
