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

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2023-07-14</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000748592</issuerCik>
        <issuerName>Eterna Therapeutics Inc.</issuerName>
        <issuerTradingSymbol>ERNA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001955231</rptOwnerCik>
            <rptOwnerName>Freebird Partners LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2800 POST OAK BLVD, SUITE 2000</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77056</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001971406</rptOwnerCik>
            <rptOwnerName>Freebird Investments LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2800 POST OAK BLVD, SUITE 2000</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77056</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001250127</rptOwnerCik>
            <rptOwnerName>HUFF CURTIS W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2800 POST OAK BLVD, SUITE 2000</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77056</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Convertible Note Shares</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>2.86</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2023-07-14</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>262237</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>2.86</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2023-07-14</value>
            </exerciseDate>
            <expirationDate>
                <value>2028-07-14</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock, par value $0.005 per share</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>262237</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>262237</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Common Stock Purchase Warrant</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>2.61</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2023-07-14</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>524474</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2023-07-14</value>
            </exerciseDate>
            <expirationDate>
                <value>2028-07-14</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock, par value $0.005 per share</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>524474</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>949402</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">This report is filed jointly by Freebird Partners LP, a Texas limited partnership (&quot;Freebird Partners&quot;), Freebird Investments LLC, a Texas limited liability company (&quot;Freebird Investments&quot;), and Curtis W. Huff (each a &quot;Reporting Person&quot; and collectively, the &quot;Reporting Persons&quot;) in connection with their respective direct and indirect ownership of common stock, par value $0.005 (&quot;Common Stock&quot;) of Eterna Therapeutics Inc. (the &quot;Company&quot;). These securities of the Company are held of record by Freebird Partners. Freebird Investments serves as the general partner of Freebird Partners. Curtis W. Huff is the sole member of Freebird Investments. By virtue of these relationships, each of Freebird Investments and Mr. Huff may be deemed to share beneficial ownership of the securities held of record by Freebird Partners.</footnote>
        <footnote id="F2">On July 13, 2023, Freebird Partners entered into that certain Securities Purchase Agreement (the &quot;Agreement&quot;), pursuant to which Freebird Partners agreed to purchase, and the Company agreed to sell, for an aggregate purchase price of $750,000, (i) a Senior Convertible Note in the principal amount of $750,000 (the &quot;Note&quot;) with a five (5) year term, and (ii) a warrant to purchase up to 524,474 shares of Common Stock (the &quot;Warrant&quot; and such transactions the &quot;Transactions&quot;. The Transactions closed on July 14, 2023. The Note may be converted at any time and from time to time after July 14, 2023, at the option of the holder, at a conversion price of $2.86 per share of Common Stock. The Warrant becomes exercisable on July 14, 2023, and may be exercised through July 14, 2028, at an exercise price of $2.61 per share of Common Stock.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Freebird Partners LP, By: Freebird Investments LLC, its general partner, By: /s/ Curtis W. Huff, Chairman and President</signatureName>
        <signatureDate>2023-07-17</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Freebird Investments LLC, By: /s/ Curtis W. Huff, Chairman and President</signatureName>
        <signatureDate>2023-07-17</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Curtis W. Huff</signatureName>
        <signatureDate>2023-07-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
