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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-09-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001752836</issuerCik>
        <issuerName>COVETRUS, INC.</issuerName>
        <issuerTradingSymbol>CVET</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001624514</rptOwnerCik>
            <rptOwnerName>CD&amp;R Investment Associates IX, Ltd.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O M+C CORPORATE SERVICES LIMITED</rptOwnerStreet1>
            <rptOwnerStreet2>P.O. BOX 309 UGLAND HSE, SOUTH CHURCH ST</rptOwnerStreet2>
            <rptOwnerCity>GEORGE TOWN</rptOwnerCity>
            <rptOwnerState>E9</rptOwnerState>
            <rptOwnerZipCode>KY1-1104</rptOwnerZipCode>
            <rptOwnerStateDescription>CAYMAN ISLANDS</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001766983</rptOwnerCik>
            <rptOwnerName>CD&amp;R VFC Holdings L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O M+C CORPORATE SERVICES LIMITED</rptOwnerStreet1>
            <rptOwnerStreet2>P.O. BOX 309 UGLAND HSE, SOUTH CHURCH ST</rptOwnerStreet2>
            <rptOwnerCity>GEORGE TOWN</rptOwnerCity>
            <rptOwnerState>E9</rptOwnerState>
            <rptOwnerZipCode>KY1-1104</rptOwnerZipCode>
            <rptOwnerStateDescription>CAYMAN ISLANDS</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>2019-09-30</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>198720</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>43.05</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11066478</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By affiliate</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Series A Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>11.10</value>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2020-05-19</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>250000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
                <footnoteId id="F6"/>
                <footnoteId id="F7"/>
                <footnoteId id="F8"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F5"/>
                <footnoteId id="F6"/>
                <footnoteId id="F7"/>
                <footnoteId id="F8"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>250000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>250000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By affiliate</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">CD&amp;R VFC Holdings, L.P. (&quot;CD&amp;R Stockholder&quot;) directly owns 11,066,478 shares of common stock (the &quot;Common Stock&quot;) of Covetrus, Inc.  (the &quot;Issuer&quot;). CD&amp;R Stockholder acquired 11,265,198 shares of Common Stock on February 7, 2019 pursuant to the agreement and plan of merger (the &quot;Merger Agreement&quot;), dated April 20, 2018, by and among Henry Schein, Inc., a Delaware corporation (&quot;Henry Schein&quot;), HS Merger Sub, Inc., a Delaware corporation and wholly-owned subsidiary of the Issuer (&quot;Merger Sub&quot;), and Direct Vet Marketing, Inc., a Delaware corporation (&quot;Vets First Choice&quot;), pursuant to which the Issuer merged with and into Vets First Choice, with Vets First Choice surviving the merger as a wholly-owned subsidiary of the Issuer (the &quot;Merger&quot;). Of the 11,265,198 shares of Common Stock issued to CD&amp;R Stockholder in the Merger, 554,651 shares were held in escrow in respect of purchase price adjustments relating to certain tax indemnity payments.</footnote>
        <footnote id="F2">On September 30, 2019, pursuant to the terms of the Merger Agreement, 198,720 of such shares held in escrow were released to the Issuer and cancelled, with the remaining 355,931 shares of Common Stock released back to CD&amp;R Stockholder.</footnote>
        <footnote id="F3">CD&amp;R Investment Associates IX, Ltd., as the general partner of CD&amp;R Stockholder, may be deemed to beneficially own the shares of Common Stock and 7.5% Series A Preferred Stock (the &quot;Preferred Stock&quot;) held by CD&amp;R Stockholder. CD&amp;R Investment Associates IX, Ltd. expressly disclaims beneficial ownership of the shares of Common Stock and Preferred Stock held by CD&amp;R Stockholder, except to the extent of its pecuniary interest therein.</footnote>
        <footnote id="F4">CD&amp;R Stockholder directly owns 250,000 shares of Preferred Stock of the Issuer, which are convertible into shares of Common Stock at a price per share of $11.10, which is subject to anti-dilution adjustments, including in the event of any stock split, stock dividend, recapitalization of similar event.</footnote>
        <footnote id="F5">The Series A Preferred Stock is convertible at any time at the option of the holder and has no expiration date. Unless certain stockholder approval is obtained, no holder may convert any share of Series A Preferred Stock if the conversion of such share would result in such holder beneficially owning more than 19.99% of the then-outstanding stockholder voting power of the Issuer.</footnote>
        <footnote id="F6">The Issuer may, at its option, require conversion of all (but not less than all) of the outstanding shares of Series A Preferred Stock to shares of the Common Stock if (i) at any time, the Issuer satisfies certain financial metrics or (ii) the volume weighted average price of the Common Stock on any trading day (a) until (but not including) the date that is two years from the issuance date, exceeds 200%, (b) from the date that is two years from the issuance date until (but not including) the date that is two years and six months from the issuance date, exceeds 195%, (c) from the date that is two years and six months from the issuance date until (but not including) the date that is three years from the issuance date, exceeds 190%, (d) from the date that is three years from the issuance date until (but not including) the date that is three years and six months from the issuance date, exceeds 185%, (continued next footnote)</footnote>
        <footnote id="F7">(e) from the date that is three years and six months from the issuance date until (but not including) the date that is four years from the issuance date, exceeds 180%, and (f) at any time thereafter, exceeds 175%, in each case, of the then-effective conversion price for at least 20 out of the 30 trailing trading days. The Series A Preferred Stock accrues dividends at a rate of 7.50% per annum, payable in cash or in additional shares of Series A Preferred Stock.</footnote>
        <footnote id="F8">Holders of Series A Preferred Stock are also entitled to receive certain dividends declared or paid on the Common Stock on an as-converted basis.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>CD&amp;R Investment Associates IX, Ltd., By: Theresa A. Gore, CFO, Treas. and Sec.</signatureName>
        <signatureDate>2020-05-20</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>CD&amp;R VFC Holdings, L.P., By: CD&amp;R Investment Associates IX, Ltd, general partner; By: /s/ Theresa A. Gore, CFO, Treas. and Sec.</signatureName>
        <signatureDate>2020-05-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
