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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-01-11</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001248899</rptOwnerCik>
            <rptOwnerName>PEREZ ARNALDO</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>CARNIVAL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>3655 NW 87TH AVE</rptOwnerStreet2>
            <rptOwnerCity>MIAMI</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33178</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>General Counsel &amp; Secretary</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2016-01-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>8898</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>70515.5022</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Grant of restricted stock made pursuant to the Carnival Corporation 2011 Stock Plan.  The restriction on the shares lapse on the third anniversary of the grant date.</footnote>
        <footnote id="F2">The grant was approved by the Compensation Committee as a total value to be received in the form of restricted shares.  The Compensation Committee also approved that the number of shares was to be determined by dividing the value by the closing price on date of grant.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Arnaldo Perez</signatureName>
        <signatureDate>2016-01-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
