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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2020-08-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001022646</issuerCik>
        <issuerName>ULTRA PETROLEUM CORP</issuerName>
        <issuerTradingSymbol>UPLCQ</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001196791</rptOwnerCik>
            <rptOwnerName>HONEYFIELD DAVID W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ULTRA PETROLEUM CORP.</rptOwnerStreet1>
            <rptOwnerStreet2>116 INVERNESS DRIVE EAST SUITE 400</rptOwnerStreet2>
            <rptOwnerCity>ENGLEWOOD</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80112</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Sr VP, Chief Financial Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-08-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>450990</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.0065</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1025024</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1025024</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.0065 to $0.0066, inclusive. The Reporting Person undertakes to provide to the Company, any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range stated.</footnote>
        <footnote id="F2">Each restricted stock unit represents a contingent right to receive one common share of the Company.</footnote>
        <footnote id="F3">136,352 of such remaining restricted stock units are time-based and will vest, if at all, in two equal annual installments beginning on November 9, 2020. 119,904 of the restricted stock units set forth in box 9 of this Form 4 are time-based and will vest, if at all, in two equal annual installments beginning March 1, 2021. The time-based awards will terminate, and the applicable restricted stock units will not vest, if the Reporting Person is not employed by the Company on the date any portion of the award is scheduled to vest.</footnote>
        <footnote id="F4">(Continued from Footnote 3) 768,768 of the restricted stock units are subject to both performance-based and time-based vesting terms. The performance-based vesting conditions are assessed based on the volume-weighted average price of the Company's common shares as measured over 60 consecutive trading days relative to pre-established price goals. Once a performance-based vesting condition is achieved, the restricted stock units that have become performance vested will time-vest over the two or three-year period following the date on which they became performance vested.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ David W. Honeyfield</signatureName>
        <signatureDate>2020-09-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
