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

    <schemaVersion>X0708</schemaVersion>

    <submissionType>D/A</submissionType>

    <testOrLive>LIVE</testOrLive>

    <primaryIssuer>
        <cik>0001797276</cik>
        <entityName>EnCap Energy Transition Fund I-A, L.P.</entityName>
        <issuerAddress>
            <street1>1100 LOUISIANA ST.</street1>
            <street2>STE. 4900</street2>
            <city>HOUSTON</city>
            <stateOrCountry>TX</stateOrCountry>
            <stateOrCountryDescription>TEXAS</stateOrCountryDescription>
            <zipCode>77002</zipCode>
        </issuerAddress>
        <issuerPhoneNumber>(713) 659-6100</issuerPhoneNumber>
        <jurisdictionOfInc>DELAWARE</jurisdictionOfInc>
        <edgarPreviousNameList>
            <previousName>Encap Energy Transition Fund I-A, L.P.</previousName>
        </edgarPreviousNameList>
        <entityType>Limited Partnership</entityType>
        <yearOfInc>
            <withinFiveYears>true</withinFiveYears>
            <value>2019</value>
        </yearOfInc>
    </primaryIssuer>

    <relatedPersonsList>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>(General Partner)</firstName>
                <lastName>EnCap Energy Transition Fund I GP, L.P.</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>1100 Louisiana Street</street1>
                <street2>Suite 4900</street2>
                <city>Houston</city>
                <stateOrCountry>TX</stateOrCountry>
                <stateOrCountryDescription>TEXAS</stateOrCountryDescription>
                <zipCode>77002</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>General Partner of Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Jason</firstName>
                <middleName>M.</middleName>
                <lastName>DeLorenzo</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>1100 Louisiana Street</street1>
                <street2>Suite 4900</street2>
                <city>Houston</city>
                <stateOrCountry>TX</stateOrCountry>
                <stateOrCountryDescription>TEXAS</stateOrCountryDescription>
                <zipCode>77002</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Managing Member of GP of Managing Member of Sole Member of GP of GP of Issuer</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>David</firstName>
                <middleName>B.</middleName>
                <lastName>Miller</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>3811 Turtle Creek Blvd.</street1>
                <street2>Suite 2100</street2>
                <city>Dallas</city>
                <stateOrCountry>TX</stateOrCountry>
                <stateOrCountryDescription>TEXAS</stateOrCountryDescription>
                <zipCode>75219</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Managing Member of GP of Managing Member of Sole Member of GP of GP of Issuer.</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Gary</firstName>
                <middleName>R.</middleName>
                <lastName>Peterson</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>1100 Louisiana Street</street1>
                <street2>Suite 4900</street2>
                <city>Houston</city>
                <stateOrCountry>TX</stateOrCountry>
                <stateOrCountryDescription>TEXAS</stateOrCountryDescription>
                <zipCode>77002</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Managing Member of GP of Managing Member of Sole Member of GP of GP of Issuer.</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>D.</firstName>
                <middleName>Martin</middleName>
                <lastName>Phillips</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>1100 Louisiana Street</street1>
                <street2>Suite 4900</street2>
                <city>Houston</city>
                <stateOrCountry>TX</stateOrCountry>
                <stateOrCountryDescription>TEXAS</stateOrCountryDescription>
                <zipCode>77002</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Managing Member of GP of Managing Member of Sole Member of GP of GP of Issuer.</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Douglas</firstName>
                <middleName>E.</middleName>
                <lastName>Swanson</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>1100 Louisiana Street</street1>
                <street2>Suite 4900</street2>
                <city>Houston</city>
                <stateOrCountry>TX</stateOrCountry>
                <stateOrCountryDescription>TEXAS</stateOrCountryDescription>
                <zipCode>77002</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Managing Member of GP of Managing Member of Sole Member of GP of GP of Issuer.</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Robert</firstName>
                <middleName>L.</middleName>
                <lastName>Zorich</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>1100 Louisiana Street</street1>
                <street2>Suite 4900</street2>
                <city>Houston</city>
                <stateOrCountry>TX</stateOrCountry>
                <stateOrCountryDescription>TEXAS</stateOrCountryDescription>
                <zipCode>77002</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Managing Member of GP of Managing Member of Sole Member of GP of GP of Issuer.</relationshipClarification>
        </relatedPersonInfo>
    </relatedPersonsList>

    <offeringData>
        <industryGroup>
            <industryGroupType>Pooled Investment Fund</industryGroupType>
            <investmentFundInfo>
                <investmentFundType>Venture Capital Fund</investmentFundType>
                <is40Act>false</is40Act>
            </investmentFundInfo>
        </industryGroup>
        <issuerSize>
            <revenueRange>Decline to Disclose</revenueRange>
        </issuerSize>
        <federalExemptionsExclusions>
            <item>06b</item>
            <item>3C</item>
            <item>3C.7</item>
        </federalExemptionsExclusions>
        <typeOfFiling>
            <newOrAmendment>
                <isAmendment>true</isAmendment>
                <previousAccessionNumber>0001797276-19-000003</previousAccessionNumber>
            </newOrAmendment>
            <dateOfFirstSale>
                <value>2019-12-30</value>
            </dateOfFirstSale>
        </typeOfFiling>
        <durationOfOffering>
            <moreThanOneYear>true</moreThanOneYear>
        </durationOfOffering>
        <typesOfSecuritiesOffered>
            <isEquityType>true</isEquityType>
            <isPooledInvestmentFundType>true</isPooledInvestmentFundType>
        </typesOfSecuritiesOffered>
        <businessCombinationTransaction>
            <isBusinessCombinationTransaction>false</isBusinessCombinationTransaction>
            <clarificationOfResponse></clarificationOfResponse>
        </businessCombinationTransaction>
        <minimumInvestmentAccepted>0</minimumInvestmentAccepted>
        <salesCompensationList></salesCompensationList>
        <offeringSalesAmounts>
            <totalOfferingAmount>Indefinite</totalOfferingAmount>
            <totalAmountSold>405113520</totalAmountSold>
            <totalRemaining>Indefinite</totalRemaining>
            <clarificationOfResponse>The total amount sold included here is the aggregate amount sold in the offering as of the date hereof for this partnership and its companion partnerships.</clarificationOfResponse>
        </offeringSalesAmounts>
        <investors>
            <hasNonAccreditedInvestors>false</hasNonAccreditedInvestors>
            <totalNumberAlreadyInvested>23</totalNumberAlreadyInvested>
        </investors>
        <salesCommissionsFindersFees>
            <salesCommissions>
                <dollarAmount>0</dollarAmount>
            </salesCommissions>
            <findersFees>
                <dollarAmount>0</dollarAmount>
            </findersFees>
            <clarificationOfResponse></clarificationOfResponse>
        </salesCommissionsFindersFees>
        <useOfProceeds>
            <grossProceedsUsed>
                <dollarAmount>0</dollarAmount>
            </grossProceedsUsed>
            <clarificationOfResponse></clarificationOfResponse>
        </useOfProceeds>
        <signatureBlock>
            <authorizedRepresentative>false</authorizedRepresentative>
            <signature>
                <issuerName>EnCap Energy Transition Fund I-A, L.P.</issuerName>
                <signatureName>/s/ Jason M. DeLorenzo</signatureName>
                <nameOfSigner>Jason M. DeLorenzo</nameOfSigner>
                <signatureTitle>Mng Mbr of GP of Mng Mbr of Sole Mbr of GP of GP of Issuer</signatureTitle>
                <signatureDate>2020-12-18</signatureDate>
            </signature>
        </signatureBlock>
    </offeringData>
</edgarSubmission>
