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

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2024-10-08</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0000061398</issuerCik>
        <issuerName>TELLURIAN INC. /DE/</issuerName>
        <issuerTradingSymbol>TELL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001697639</rptOwnerCik>
            <rptOwnerName>Sharafeldin Khaled</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1201 LOUISIANA STREET, SUITE 3100</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77002</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Accounting Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2024-10-08</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>769883</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">This amount includes (a) 243,383 shares of common stock of Tellurian Inc. (&quot;Tellurian&quot;) and (b) 526,500 shares of restricted stock of Tellurian that were scheduled to vest upon the affirmative final investment decision by the board of directors of Tellurian with respect to the Driftwood LNG project.</footnote>
        <footnote id="F2">On October 8, 2024, pursuant to the Agreement and Plan of Merger dated as of July 21, 2024 (the &quot;Merger Agreement&quot;) by and among Woodside Energy Holdings (NA) LLC (&quot;Parent&quot;), Woodside Energy (Transitory) Inc. (&quot;Merger Sub&quot;), and Tellurian, Merger Sub merged with and into Tellurian (the &quot;Merger&quot;), with Tellurian surviving the Merger as a direct, wholly-owned subsidiary of Parent. Pursuant to the Merger Agreement, at the effective time of the Merger, the shares of Tellurian's common stock and restricted stock converted into the right to receive $1.00 per share in cash.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Khaled Sharafeldin</signatureName>
        <signatureDate>2024-10-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
