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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2020-01-02</periodOfReport>

    <dateOfOriginalSubmission>2020-01-03</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000712771</issuerCik>
        <issuerName>ConnectOne Bancorp, Inc.</issuerName>
        <issuerTradingSymbol>CNOB</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001393119</rptOwnerCik>
            <rptOwnerName>Sokolich Mark</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CONNECTONE BANCORP, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>301 SLYVAN AVENUE</rptOwnerStreet2>
            <rptOwnerCity>ENGLEWOOD CLIFFS</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07632</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-01-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>67881</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>83131</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Includes 63,672 shares of common stock held jointly with Mr. Sokolich's spouse, and 4,209 shares held in an IRA.</footnote>
        <footnote id="F2">Received pursuant to the merger agreement between Issuer and Bancorp of New Jersey, Inc. (&quot;BKJ&quot;) dated August 15, 2019 (the &quot;Merger Agreement&quot;), pursuant to which BKJ was merged with and into the Issuer on January 2, 2020. At the effective time of the merger, each share of BKJ's common stock converted into the right to receive either (i) $16.25 in cash or (ii) 0.780 of a share of the Issuer's common stock, subject to certain election and proration procedures. Mr. Sokolich elected to receive the Issuer's common stock in exchange for his BKJ shares. On the trading day immediately preceding closing, the closing price of BKJ's common stock was $17.89 per share, and the closing price of Issuer's common stock was $25.72 per share.</footnote>
    </footnotes>

    <remarks>On January 3, 2020, Mr. Sokolich filed a Form 4 with respect to acquisition of certain shares of the Issuers common stock in connection with the consummation of the merger agreement between the Issuer and Bancorp of New Jersey, Inc. dated August 15, 2019.  In such report it was noted that the number of shares acquired were estimates and based on certain proration and election procedures.   This Form 4 reflects the final calculation with respect to the shares acquired.</remarks>

    <ownerSignature>
        <signatureName>/s/ Laura Criscione, POA</signatureName>
        <signatureDate>2020-01-30</signatureDate>
    </ownerSignature>
</ownershipDocument>
