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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2014-03-03</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001328581</issuerCik>
        <issuerName>BOISE CASCADE Co</issuerName>
        <issuerTradingSymbol>BCC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001174463</rptOwnerCik>
            <rptOwnerName>MADIGAN JOHN W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O BOISE CASCADE COMPANY</rptOwnerStreet1>
            <rptOwnerStreet2>1111 WEST JEFFERSON STREET, SUITE 300</rptOwnerStreet2>
            <rptOwnerCity>BOISE</rptOwnerCity>
            <rptOwnerState>ID</rptOwnerState>
            <rptOwnerZipCode>83702</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, par value $0.01</value>
            </securityTitle>
            <transactionDate>
                <value>2014-03-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>14290</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>14290</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On March 3, 2014, Boise Cascade Holdings, L.L.C. (&quot;BC Holdings&quot;) made a pro rata distribution for no consideration of 7,785,938 shares of Boise Cascade Company's common stock, par value $0.01 per share (collectively, the &quot;Shares&quot;), to its members.  Forest Products Holdings, L.L.C. (&quot;FPH&quot;), BC Holdings' controlling equityholder, then made a pro rata distribution for no consideration of 6,228,265 of the Shares to its members, including Mr. Madigan, on the same date.  Mr. Madigan is a non-managing member of FPH.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ John T. Sahlberg, as Attorney in Fact</signatureName>
        <signatureDate>2014-03-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
