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

    <schemaVersion>X0304</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-12-20</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000775662</issuerCik>
        <issuerName>VIST FINANCIAL CORP</issuerName>
        <issuerTradingSymbol>VIST</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001225232</rptOwnerCik>
            <rptOwnerName>HOPKINS CHARLES J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1240 BROADCASTING ROAD PO BOX 6219</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>WHOMISSING</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>19610</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>2011-12-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>334</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.45</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>70133</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>COMMON STOCK</value>
            </securityTitle>
            <transactionDate>
                <value>2011-12-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>666</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.45</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>70799</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The transaction represents the grant of restricted stock award to the reporting person under the Issuer's 2007 Incentive Plan.  As required by the Interim Final Rule on TARP Standards for Compensation and Corporate Governance on June 15, 2009 (the Rule), the resticted stock will not vest until the second anniversary on the date of grant, provided the executive remains continuously employed with the Issuer and, once vested as otherwise described herein, the shares may not be sold or transferred by the executive except to the extent the issuer has repaid its financial obligation to the US Dept of the Treasury (the Treasury) or under the Rule or other guidance that may be issued by the Treasury or other government agency.</footnote>
        <footnote id="F2">Subject to Footnote (1), the restricted stock award will vest in three equal installments beginning on December 20, 2012 and continuing each anniversary thereafter through December 20, 2014.</footnote>
        <footnote id="F3">Subject to Footnote (1), 50% of the restricted stock award will vest in three equal installments based on the satisfaction of certain corporate-wide performance criteria for the fiscal year ending December 31, 2012.  The balance will vest in three equal installments based on the satisfaction of certain individual performance criteria for the fiscal year ending December 31, 2012.  If the relevant criteria are achieved, 1/3 will vest on January 29, 2013, 1/3 will vest on December 20,2013, and 1/3 will vest on December 20, 2014.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>JENETTE L ECK, ATTORNEY-IN-FACT</signatureName>
        <signatureDate>2011-12-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
