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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-10-19</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001276187</issuerCik>
        <issuerName>Energy Transfer LP</issuerName>
        <issuerTradingSymbol>ET</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001554641</rptOwnerCik>
            <rptOwnerName>Ramsey Matthew S.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>8111 WESTCHESTER DRIVE, SUITE 600</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75225</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Units</value>
            </securityTitle>
            <transactionDate>
                <value>2018-10-19</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>361289</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>425926</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Phantom Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F3"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Units</value>
                    <footnoteId id="F3"/>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>223908</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>223908</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Acquisition in connection with the merger of a wholly owned subsidiary of Energy Transfer Equity, L.P. (&quot;ETE&quot;) with Energy Transfer Partners, L.P. (&quot;ETP&quot;), with ETP continuing as the surviving entity and becoming a wholly owned subsidiary of ETE (the &quot;Merger&quot;).  On October 18, 2018, the last trading day for the ETP common units, the closing price of ETP's common units was $21.47 per unit and the closing price of ETE's common units was $16.82 per unit. Each ETP common unit outstanding was converted into the right to receive 1.28 ETE common units. As part of the Merger, ETE changed its name to &quot;Energy Transfer LP&quot; and its common units began trading on the New York Stock Exchange (&quot;NYSE&quot;) under the &quot;ET&quot; ticker symbol when the market opened on Friday, October 19, 2018.</footnote>
        <footnote id="F2">331,806 of the reported units represent restricted unit awards granted under one of the Energy Transfer LP Long-Term Incentive Plans that vest 60% after three years and 40% after five years.</footnote>
        <footnote id="F3">An award of phantom units granted under the Amended and Restated Energy Transfer LP Long-Term Incentive Plan scheduled to vest 60% on December 5, 2020 and 40% on December 5, 2022 and may vest in Partnership units, cash or other securities.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Peggy J. Harrison, Attorney-in-fact for Mr. Ramsey</signatureName>
        <signatureDate>2018-10-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
