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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-05-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001377630</issuerCik>
        <issuerName>National CineMedia, Inc.</issuerName>
        <issuerTradingSymbol>NCMI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001661466</rptOwnerCik>
            <rptOwnerName>AMC STARPLEX, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE AMC WAY</rptOwnerStreet1>
            <rptOwnerStreet2>11500 ASH STREET</rptOwnerStreet2>
            <rptOwnerCity>LEAWOOD</rptOwnerCity>
            <rptOwnerState>KS</rptOwnerState>
            <rptOwnerZipCode>66211</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000780392</rptOwnerCik>
            <rptOwnerName>AMERICAN MULTI-CINEMA, INC.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE AMC WAY</rptOwnerStreet1>
            <rptOwnerStreet2>11500 ASH STREET</rptOwnerStreet2>
            <rptOwnerCity>LEAWOOD</rptOwnerCity>
            <rptOwnerState>KS</rptOwnerState>
            <rptOwnerZipCode>66211</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001411579</rptOwnerCik>
            <rptOwnerName>AMC ENTERTAINMENT HOLDINGS, INC.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE AMC WAY</rptOwnerStreet1>
            <rptOwnerStreet2>11500 ASH STREET</rptOwnerStreet2>
            <rptOwnerCity>LEAWOOD</rptOwnerCity>
            <rptOwnerState>KS</rptOwnerState>
            <rptOwnerZipCode>66211</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>National Cinemedia, Inc. Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2018-05-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>98000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.4187</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>902000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>National Cinemedia, Inc. Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2018-05-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>902000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.2079</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The price reflected is a weighted average price.  The reporting person undertakes to provide the Issuer, any security holder of the Issuer, or the staff of the Commission, upon request, full information regarding the number of shares sold at each price included in the weighted average price.</footnote>
        <footnote id="F2">The reported securities are held directly by AMC Starplex, LLC (&quot;AMCS&quot;), indirectly by American Multi-Cinema, Inc. (&quot;AMCI&quot;) as the parent of AMCS, and indirectly by AMC Entertainment Holdings, Inc. as the parent of AMCI.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Edwin F. Gladbach, Vice President Legal &amp; Asst Secretary, AMC Starplex, LLC</signatureName>
        <signatureDate>2018-06-01</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Edwin F. Gladbach, Vice President Legal &amp; Asst Secretary, American Multi-Cinema, Inc.</signatureName>
        <signatureDate>2018-06-01</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Edwin F. Gladbach, Vice President Legal &amp; Asst Secretary, AMC Entertainment Holdings, Inc.</signatureName>
        <signatureDate>2018-06-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
