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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-02-09</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001819035</issuerCik>
        <issuerName>Metromile, Inc.</issuerName>
        <issuerTradingSymbol>MILE</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001843122</rptOwnerCik>
            <rptOwnerName>Preston Dan</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O METROMILE, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>425 MARKET STREET, SUITE 700</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94105</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Executive Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-02-09</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1700565</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1700565</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Received pursuant to the Agreement and Plan of Merger and Reorganization, dated as of November 24, 2020, as amended January 12, 2021 and further amended February 8, 2021, by and among INSU Acquisition Corp. II (n/k/a Metromile, Inc.) (the &quot;Issuer&quot;), INSU II Merger Sub Corp. and MetroMile, Inc. (n/k/a Metromile Operating Company) (&quot;Legacy Metromile&quot;) (the &quot;Merger Agreement&quot;) pursuant to which, through a series of mergers Legacy Metromile became a direct, wholly-owned subsidiary of the Issuer. Pursuant to the Merger Agreement former securityholders of Legacy Metromile will receive additional shares of the Issuer's common stock (the &quot;Additional Shares&quot;) if the closing sale price of the Issuer's common stock exceeds $15.00 per share for 20 out of any 30 consecutive trading days during the first two years following the closing of the merger.</footnote>
        <footnote id="F2">Includes 330,899 shares subject to restricted stock units (&quot;RSU&quot;) and 203,233 shares to be received as Additional Shares. Each RSU represents a contingent right to receive one share of the Issuer's common stock upon settlement.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Dan Preston</signatureName>
        <signatureDate>2021-02-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
