<ownershipDocument><schemaVersion>X0101</schemaVersion>    <documentType>4</documentType><periodOfReport>2003-05-23</periodOfReport><notSubjectToSection16>0</notSubjectToSection16><issuer><issuerCik>0000737468</issuerCik><issuerName>WASHINGTON TRUST BANCORP INC</issuerName>        <issuerTradingSymbol>WASH</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>0001212014</rptOwnerCik><rptOwnerName>ORSINGER VICTOR J II</rptOwnerName></reportingOwnerId><reportingOwnerAddress><rptOwnerStreet1>  </rptOwnerStreet1><rptOwnerStreet2>  </rptOwnerStreet2><rptOwnerCity>  </rptOwnerCity><rptOwnerState>  </rptOwnerState><rptOwnerZipCode>  </rptOwnerZipCode></reportingOwnerAddress><reportingOwnerRelationship><isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle></officerTitle><otherText></otherText></reportingOwnerRelationship></reportingOwner><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-05-23</value></transactionDate><transactionCoding><transactionFormType>5</transactionFormType><transactionCode>G</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>250</value></transactionShares><transactionValue><value>0</value></transactionValue><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>10491</value><footnoteId id="F1"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>Victor J.Orsinger Living Trust</value></natureOfOwnership></ownershipNature></nonDerivativeSecurity><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-05-23</value></transactionDate><transactionCoding><transactionFormType>5</transactionFormType><transactionCode>G</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>250</value></transactionShares><transactionValue><value>0</value></transactionValue><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>10241</value><footnoteId id="F1"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>Victor J.Orsinger Living Trust</value></natureOfOwnership></ownershipNature></nonDerivativeSecurity><footnotes><footnote id="F1">The reporting person also holds indirect ownership interests in 9,945 shares held by his wife's living trust.  In addition to common stock holdings, the reporting person has the right to purchase 1,688 shares of common stock exercisable at $12.1667 with an expiration date of 4/29/2007, 1,688 shares of common stock exercisable at $21.3333 with an expiration date of 4/28/2008, 1,688 shares of common stock exercisable at $19.50 with an expiration date of 4/27/2009, 2,000 shares of common stock exercisable at $15.50 with an expiration date of 4/25/2010, 2,000 shares of common stock exercisable at $17.85 with an expiration date of 4/24/2011 and 2,000 shares of common stock exercisable at $20.23 with an expiration date of 4/23/2012.</footnote></footnotes><ownerSignature><signatureName>David V. Devault EVP, Treas, CFO-POA</signatureName><signatureDate>2003-06-11</signatureDate></ownerSignature></ownershipDocument>
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X0101
4
2003-05-23
0
0000737468
WASHINGTON TRUST BANCORP INC
WASH
0001212014
ORSINGER VICTOR J II
1
0
0
0
Common Stock
2003-05-23
5
G
0
250
0
D
10491
I
Victor J.Orsinger Living Trust
Common Stock
2003-05-23
5
G
0
250
0
D
10241
I
Victor J.Orsinger Living Trust
The reporting person also holds indirect ownership interests in 9,945 shares held by his wife's living trust.  In addition to common stock holdings, the reporting person has the right to purchase 1,688 shares of common stock exercisable at $12.1667 with an expiration date of 4/29/2007, 1,688 shares of common stock exercisable at $21.3333 with an expiration date of 4/28/2008, 1,688 shares of common stock exercisable at $19.50 with an expiration date of 4/27/2009, 2,000 shares of common stock exercisable at $15.50 with an expiration date of 4/25/2010, 2,000 shares of common stock exercisable at $17.85 with an expiration date of 4/24/2011 and 2,000 shares of common stock exercisable at $20.23 with an expiration date of 4/23/2012.
David V. Devault EVP, Treas, CFO-POA
2003-06-11