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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-02-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000790816</issuerCik>
        <issuerName>BRANDYWINE REALTY TRUST</issuerName>
        <issuerTradingSymbol>BDN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000944673</rptOwnerCik>
            <rptOwnerName>SWEENEY GERARD H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2929 WALNUT ST.</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1700</rptOwnerStreet2>
            <rptOwnerCity>PHILADELPHIA</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>19104</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President and CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Shares of Beneficial Interest</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2019-02-01</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>89097</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>14.96</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1253256</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Shares of Beneficial Interest</value>
                <footnoteId id="F4"/>
            </securityTitle>
            <transactionDate>
                <value>2019-02-01</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>33398</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>14.96</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1219858</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Reflects the delivery of common shares under the reporting person's 2016-2018 Restricted Performance Share Unit Award.</footnote>
        <footnote id="F2">This filing also reports in the ending balance of shares owned, 1,868 additional common shares acquired under the Company's Employee Share Purchase Plan (ESPP). The ESPP shares were purchased following the Reporting Person's last Section 16 filing. Under the ESPP, 888 shares were acquired on September 10, 2018 at a transaction price of $14.08 per share and 980 shares were acquired on December 6, 2018 at a transaction price of $12.75 per share. The ESPP provides for the purchase of fractional shares. The numbers reported herein are rounded to the nearest whole number.</footnote>
        <footnote id="F3">This filing also reports in the ending balance 2,356.38 additional common shares acquired under the Company's Dividend Reinvestment Plan (DRIP). Under the DRIP, 688.80 shares were acquired on July 24, 2018 at a transaction price of $16.33 per share, 789.86 shares were acquired on October 22, 2018 at a transaction price of $14.60 and 877.73 shares were acquired on January 24, 2019 at a transaction price of $14.25 per share.</footnote>
        <footnote id="F4">Reflects common shares withheld to satisfy payroll taxes due upon delivery of common shares under the reporting person's 2016-2018 Restricted Performance Share Unit Award.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Gerard H. Sweeney</signatureName>
        <signatureDate>2019-02-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
