<ownershipDocument><schemaVersion>X0101</schemaVersion>    <documentType>4</documentType><periodOfReport>2003-06-17</periodOfReport><notSubjectToSection16>0</notSubjectToSection16><issuer><issuerCik>0000737468</issuerCik><issuerName>WASHINGTON TRUST BANCORP INC</issuerName>        <issuerTradingSymbol>WASH</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>0001212011</rptOwnerCik><rptOwnerName>HOXSIE KATHERINE W</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>2003-06-17</value></transactionDate><transactionCoding><transactionFormType>5</transactionFormType><transactionCode>G</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>1000</value></transactionShares><transactionValue><value>0</value></transactionValue><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>92453</value><footnoteId id="F1"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>Joseph J. Kirby (spouse)</value></natureOfOwnership></ownershipNature></nonDerivativeSecurity><footnotes><footnote id="F1">The reporting person also holds direct ownership interests in 13,670 shares and indirect ownership interests in 36,982 shares held by trust.  In addition to common stock holdings, the reporting person has the right to purchase 5,063 shares of common stock exercisable at $6.7407 with an expiration date of 4/25/2005, 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,  2,000 shares of common stock exercisable at $20.23 with an expiration date of 4/23/2012 and  2,000 shares of common stock exercisable at $20.62 with an expiration date of 4/29/2013.</footnote></footnotes><ownerSignature><signatureName>David V. Devault EVP, Treas, CFO-POA</signatureName><signatureDate>2003-06-19</signatureDate></ownerSignature></ownershipDocument>
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X0101
4
2003-06-17
0
0000737468
WASHINGTON TRUST BANCORP INC
WASH
0001212011
HOXSIE KATHERINE W
1
0
0
0
Common Stock
2003-06-17
5
G
0
1000
0
D
92453
I
Joseph J. Kirby (spouse)
The reporting person also holds direct ownership interests in 13,670 shares and indirect ownership interests in 36,982 shares held by trust.  In addition to common stock holdings, the reporting person has the right to purchase 5,063 shares of common stock exercisable at $6.7407 with an expiration date of 4/25/2005, 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,  2,000 shares of common stock exercisable at $20.23 with an expiration date of 4/23/2012 and  2,000 shares of common stock exercisable at $20.62 with an expiration date of 4/29/2013.
David V. Devault EVP, Treas, CFO-POA
2003-06-19