<ownershipDocument><schemaVersion>X0101</schemaVersion>    <documentType>4</documentType><periodOfReport>2003-06-26</periodOfReport><notSubjectToSection16>0</notSubjectToSection16><issuer><issuerCik>0000737468</issuerCik><issuerName>WASHINGTON TRUST BANCORP INC</issuerName>        <issuerTradingSymbol>WASH</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>0001212017</rptOwnerCik><rptOwnerName>PERRY HARVEY C II</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>SVP &amp; Secretary</officerTitle><otherText></otherText></reportingOwnerRelationship></reportingOwner><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-06-26</value></transactionDate><transactionCoding><transactionFormType>5</transactionFormType><transactionCode>G</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>150</value></transactionShares><transactionValue><value>0</value></transactionValue><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>9850</value><footnoteId id="F1"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></nonDerivativeSecurity><footnotes><footnote id="F1">The reporting person also holds indirect ownership interests in 9,226 shares held by his wife.  In addition to common stock holdings, the reporting person has the right to purchase 6,683 shares of common stock exercisable at $6.4445 with an expiration date of 6/2/2004, 6,182 shares of common stock exercisable at $7.6297 with an expiration date of 5/12/2005, 7,541 shares of common stock exercisable at $9.7778 with an expiration date of 5/13/2006, 6,750 shares of common stock exercisable at $11.5555 with an expiration date of 5/12/2007, 4,523 shares of common stock exercisable at $18.25 with an expiration date of 12/15/2007, 4,975 shares of common stock exercisable at $17.50 with an expiration date of 5/17/2009, 10,000 shares of common stock exercisable at $15.25 with an expiration date of 5/15/2010, 5,900 shares of common stock exercisable at $17.80 with an expiration date of 4/23/2011, 5,430 shares of common stock exercisable at $20.03 with an expiration date of 4/22/2012 and 5,440 shares of common stock exercisable at $20.00 with an expiration date of 5/12/2013.</footnote></footnotes><ownerSignature><signatureName>David V. Devault EVP, Treas, CFO-POA</signatureName><signatureDate>2003-06-27</signatureDate></ownerSignature></ownershipDocument>
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X0101
4
2003-06-26
0
0000737468
WASHINGTON TRUST BANCORP INC
WASH
0001212017
PERRY HARVEY C II
0
1
0
0
SVP & Secretary
Common Stock
2003-06-26
5
G
0
150
0
D
9850
D
The reporting person also holds indirect ownership interests in 9,226 shares held by his wife.  In addition to common stock holdings, the reporting person has the right to purchase 6,683 shares of common stock exercisable at $6.4445 with an expiration date of 6/2/2004, 6,182 shares of common stock exercisable at $7.6297 with an expiration date of 5/12/2005, 7,541 shares of common stock exercisable at $9.7778 with an expiration date of 5/13/2006, 6,750 shares of common stock exercisable at $11.5555 with an expiration date of 5/12/2007, 4,523 shares of common stock exercisable at $18.25 with an expiration date of 12/15/2007, 4,975 shares of common stock exercisable at $17.50 with an expiration date of 5/17/2009, 10,000 shares of common stock exercisable at $15.25 with an expiration date of 5/15/2010, 5,900 shares of common stock exercisable at $17.80 with an expiration date of 4/23/2011, 5,430 shares of common stock exercisable at $20.03 with an expiration date of 4/22/2012 and 5,440 shares of common stock exercisable at $20.00 with an expiration date of 5/12/2013.
David V. Devault EVP, Treas, CFO-POA
2003-06-27