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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-04-14</periodOfReport>

    <issuer>
        <issuerCik>0000815097</issuerCik>
        <issuerName>CARNIVAL CORP</issuerName>
        <issuerTradingSymbol>CCL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001489421</rptOwnerCik>
            <rptOwnerName>BAND SIR JONATHON</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>33 AUCKLAND ROAD EAST</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HAMPSHIRE</rptOwnerCity>
            <rptOwnerState>X0</rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription>UNITED KINGDOM</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2016-04-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>3102</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>23898.937</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Issued pursuant to the Carnival Corporation 2011 Stock Plan. The restriction on the shares lapses on the third anniversary of the grant date.</footnote>
        <footnote id="F2">The Board of Directors approved a value of $160,000 to be awarded to the reporting person in the form of restricted shares.  The number of shares was determined by dividing the closing price of a share of Carnival Corporation common stock on April 14, 2016 and dividing it into $160,000, then rounding down to the nearest whole share.</footnote>
        <footnote id="F3">Includes shares acquired pursuant to the dividend reinvestment feature of the reporting person's brokerage account.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Sir Jonathon Band</signatureName>
        <signatureDate>2016-04-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
