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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2013-03-20</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001504008</issuerCik>
        <issuerName>BankUnited, Inc.</issuerName>
        <issuerTradingSymbol>BKU</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001026610</rptOwnerCik>
            <rptOwnerName>ROSS WILBUR L JR</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>319 CLEMATIS STREET</rptOwnerStreet1>
            <rptOwnerStreet2>ROOM 1000 (10TH FLOOR)</rptOwnerStreet2>
            <rptOwnerCity>WEST PALM BEACH</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33401</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001431791</rptOwnerCik>
            <rptOwnerName>El Vedado, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>319 CLEMATIS STREET</rptOwnerStreet1>
            <rptOwnerStreet2>ROOM 1000 (10TH FLOOR)</rptOwnerStreet2>
            <rptOwnerCity>WEST PALM BEACH</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33401</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001431792</rptOwnerCik>
            <rptOwnerName>WLR/GS Master Co-Investment, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WL ROSS &amp; CO. LLC</rptOwnerStreet1>
            <rptOwnerStreet2>1166 AVENUE OF THE AMERICAS</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001431793</rptOwnerCik>
            <rptOwnerName>WLR Master Co-Investment GP LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WL ROSS &amp; CO. LLC</rptOwnerStreet1>
            <rptOwnerStreet2>1166 AVENUE OF THE AMERICAS</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001422834</rptOwnerCik>
            <rptOwnerName>WLR IV PARALLEL ESC LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WL ROSS &amp; CO. LLC</rptOwnerStreet1>
            <rptOwnerStreet2>1166 AVENUE OF THE AMERICAS</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001429294</rptOwnerCik>
            <rptOwnerName>INVESCO WLR IV Associates LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WL ROSS &amp; CO. LLC</rptOwnerStreet1>
            <rptOwnerStreet2>1166 AVENUE OF THE AMERICAS</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001128452</rptOwnerCik>
            <rptOwnerName>Invesco Private Capital, Inc.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WL ROSS &amp; CO. LLC</rptOwnerStreet1>
            <rptOwnerStreet2>1166 AVENUE OF THE AMERICAS</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001414643</rptOwnerCik>
            <rptOwnerName>WLR Recovery Fund IV LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WL ROSS &amp; CO. LLC</rptOwnerStreet1>
            <rptOwnerStreet2>1166 AVENUE OF THE AMERICAS</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001429295</rptOwnerCik>
            <rptOwnerName>WLR Recovery Associates IV LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WL ROSS &amp; CO. LLC</rptOwnerStreet1>
            <rptOwnerStreet2>1166 AVENUE OF THE AMERICAS</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001431790</rptOwnerCik>
            <rptOwnerName>WL Ross Group, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WL ROSS &amp; CO. LLC</rptOwnerStreet1>
            <rptOwnerStreet2>1166 AVENUE OF THE AMERICAS</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</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, par value $0.01 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2013-03-20</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>721500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>24.745</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8189631</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>100</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Reflects the sale of BankUnited, Inc.'s common stock, par value $0.01 per share (&quot;Common Stock&quot;), consisting of 654,165 shares sold by WLR Recovery Fund IV, L.P., 2,627 shares sold by WLR IV Parallel ESC, L.P. and 64,708 shares sold by WLR/GS Master Co-Investment, L.P. on March 20, 2013 pursuant to the underwriters' full exercise of their option to purchase additional shares of common stock in connection with a secondary offering of BankUnited, Inc.</footnote>
        <footnote id="F2">Each of the reporting persons disclaims beneficial ownership of any securities except to the extent of its pecuniary interest therein.</footnote>
        <footnote id="F3">WLR Recovery Fund IV, L.P. (&quot;Fund IV&quot;) owns 7,425,314 shares of Common Stock of the issuer. Wilbur L. Ross, Jr. is the president and chief executive officer of WL Ross &amp; Co. LLC and the managing member of El Vedado, LLC. El Vedado, LLC is the general partner of WL Ross Group, L.P., which in turn is the managing member of WLR Recovery Associates IV LLC. WLR Recovery Associates IV LLC is the general partner of Fund IV. WL Ross &amp; Co. LLC serves as the investment manager to Fund IV. Accordingly, each of WL Ross &amp; Co. LLC, Wilbur L. Ross, Jr., El Vedado, LLC, WL Ross Group, L.P. and WLR Recovery Associates IV LLC may be deemed to be a beneficial owner of some or all the shares of Common Stock owned by Fund IV.</footnote>
        <footnote id="F4">WLR IV Parallel ESC, L.P. (the &quot;Parallel Fund&quot;) owns 29,821 shares of Common Stock of the issuer. Wilbur L. Ross, Jr. is the managing member of El Vedado, LLC and the chairman and president of Invesco Private Capital, Inc. El Vedado, LLC is the general partner of WL Ross Group, L.P., which in turn is the managing member of WLR Recovery Associates IV LLC. Invesco Private Capital, Inc. is the managing member of INVESCO WLR IV Associates LLC, which in turn is the general partner of the Parallel Fund. INVESCO WLR IV Associates LLC and WLR Recovery Associates IV LLC have entered into a parallel investment agreement pursuant to which WLR Recovery Associates IV LLC has been appointed as representative and attorney of the Parallel Fund to, among other things, exercise all rights, powers and privileges with respect to the Common Stock owned by the Parallel Fund and to take whatever action, including voting such Common Stock, as WLR Recovery Associates IV LLC (continued in footnote 5).</footnote>
        <footnote id="F5">(continued from footnote 4) in its discretion deems fit. Accordingly, each of Wilbur L. Ross, Jr., El Vedado, LLC, WL Ross Group, L.P., WLR Recovery Associates IV LLC, Invesco Private Capital, Inc. and INVESCO WLR IV Associates LLC may be deemed to be a beneficial owner of some or all the shares of Common Stock owned by the Parallel Fund.</footnote>
        <footnote id="F6">WLR/GS Master Co-Investment L.P. (the &quot;Co-Invest Fund&quot;) owns 734,496 shares of Common Stock of the issuer. Wilbur L. Ross, Jr. is the president and chief executive officer of WL Ross &amp; Co. LLC and the managing member of El Vedado, LLC. El Vedado, LLC is the general partner of WL Ross Group, L.P., which in turn is the managing member of WLR Master Co-Investment GP, LLC. WLR Master Co-Investment GP, LLC is the general partner of the Co-Invest Fund. WL Ross &amp; Co. LLC serves as the investment manager to the Co-Invest Fund. Accordingly, each of WL Ross &amp; Co. LLC, Wilbur L. Ross, Jr., El Vedado, LLC, WL Ross Group, L.P. and WLR Master Co-Investment GP, LLC may be deemed to be a beneficial owner of some or all the shares of Common Stock owned by the Co-Invest Fund.</footnote>
    </footnotes>

    <remarks>Due to technical limitations in the number of reporting persons that can be included in a Section 16 filing, this Form 4 is being filed in two separate filings.  Please see exhibit 99.1 (Joint Filer Information) attached hereto.  This is filing no. 1 of 2.  Filing no. 2 is made solely for the purpose of including WL Ross &amp; Co. LLC as a reporting person in this Form 4.</remarks>

    <ownerSignature>
        <signatureName>/s/ Rajinder P. Singh, as Attorney-in-Fact</signatureName>
        <signatureDate>2013-03-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
