<SUBMISSION>
<ACCESSION-NUMBER>0001216709-03-000002
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20030505
<FILING-DATE>20030528
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>OLSON RICHARD A
<CIK>0001216709
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-16335
<FILM-NUMBER>03721200
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>C/O WILLIAMS CO INC
<STREET2>ONE WILLIAMS CENTER 720-A
<CITY>TULSA
<STATE>OK
<ZIP>74172
<PHONE>9185733602
</BUSINESS-ADDRESS>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>WILLIAMS ENERGY PARTNERS L P
<CIK>0001126975
<ASSIGNED-SIC>4610
<IRS-NUMBER>731599053
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>ONE WILLIAMS CENTER
<CITY>TULSA
<STATE>OK
<ZIP>74172
<PHONE>9185732000
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>ONE WILLIAMS CENTER
<CITY>TULSA
<STATE>OK
<ZIP>74171
</MAIL-ADDRESS>
</ISSUER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0101</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-05-05</periodOfReport>
    <issuer>
        <issuerCik>0001126975</issuerCik>
        <issuerName>WILLIAMS ENERGY PARTNERS L P</issuerName>
        <issuerTradingSymbol>WEG</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId>
            <rptOwnerCik>0001216709</rptOwnerCik>
            <rptOwnerName>OLSON RICHARD A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Vice President</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeSecurity><securityTitle><value>Common Units</value></securityTitle><transactionDate><value>2003-05-05</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>P</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>500</value></transactionShares><transactionValue><value>41.99</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>500</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></nonDerivativeSecurity><nonDerivativeSecurity><securityTitle><value>Common Units</value></securityTitle><transactionDate><value>2003-05-07</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>P</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>250</value></transactionShares><transactionValue><value>41.25</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>750</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></nonDerivativeSecurity><footnotes/><ownerSignature><signatureName>Richard A. Olson</signatureName><signatureDate>2003-05-28</signatureDate></ownerSignature></ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
