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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2014-11-25</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001508171</issuerCik>
        <issuerName>Solar Senior Capital Ltd.</issuerName>
        <issuerTradingSymbol>SUNS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001240586</rptOwnerCik>
            <rptOwnerName>SPOHLER BRUCE J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SOLAR SENIOR CAPITAL LTD.</rptOwnerStreet1>
            <rptOwnerStreet2>500 PARK AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Operating Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2014-11-26</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>44500</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>476652</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F5"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2014-11-25</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F6"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>15748.487</value>
                    <footnoteId id="F5"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F5"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock, par value $0.01 per share</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>15748.487</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>15748.487</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">In-kind distribution without consideration to non-reporting person.</footnote>
        <footnote id="F2">In-kind distribution of 44,500 shares of common stock of Solar Senior Capital Ltd. (the &quot;Issuer&quot;) to other holders of membership interests of Solar Senior Capital Investors, LLC (&quot;Solar Senior Investors&quot;). Such in-kind distribution did not result in any change in pecuniary interest of the reporting person.</footnote>
        <footnote id="F3">Includes 455,500 shares held by Solar Senior Investors and 100 shares held by Solar Capital Management, LLC (&quot;Solar Management&quot;), a portion of both of which may be deemed to be beneficially owned by Mr. Spohler and by Mr. Gross by virtue of their collective ownership interest therein. Also includes 21,052 shares held by Solar Capital Partners Employee Stock Plan LLC (the &quot;SCP Plan&quot;), which is controlled by Solar Capital Partners LLC (&quot;Solar Capital Partners&quot;). Mr. Spohler and Mr. Gross may be deemed to beneficially own a portion of the shares held by the SCP Plan by virtue of their collective ownership interest in Solar Capital Partners.</footnote>
        <footnote id="F4">(Continued from Footnote 3) Mr. Spohler disclaims beneficial ownership of any of the Issuer's securities directly held by Solar Senior Investors, Solar Management or the SCP Plan except to the extent of his pecuniary interest therein, and this report shall not be deemed an admission that Mr. Spohler is the beneficial owner of such securities for purposes of Section 16 or any other purpose.</footnote>
        <footnote id="F5">Grants of Restricted Stock Units (&quot;RSUs&quot;) with respect to 15,748.4870 shares held by the SCP Plan, which is controlled by Solar Capital Partners, to certain of its employees pursuant to Restricted Stock Unit Agreements, dated November 25, 2014.  Mr. Spohler and Michael S. Gross may be deemed to beneficially own the shares held by SCP Plan by virtue of their collective ownership interest in Solar Capital Partners.  Shares of the Issuer's common stock underlying the RSUs are scheduled to vest in installments of 50% on March 1, 2016 and 50% on March 1, 2017.  Upon settlement, the RSUs will become payable on a one-for-one basis in shares of the Issuer's common stock or the cash value thereof at the election of the SCP Plan administrators, Messrs. Spohler and Gross.</footnote>
        <footnote id="F6">Pursuant to the SEC staff no-action letter to Babson Capital Management LLC (pub. avail. Dec. 14, 2006), an employee benefit plan sponsored by an investment adviser (or an affiliated person of an investment adviser) to a closed-end investment company regulated under the Investment Company Act of 1940, as amended, that offers plan participants equity securities of such investment company is considered an &quot;employee benefit plan sponsored by the issuer&quot; for the purposes of Rule 16b-3 under the Securities Exchange Act of 1934, as amended.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Bruce J. Spohler</signatureName>
        <signatureDate>2014-11-26</signatureDate>
    </ownerSignature>
</ownershipDocument>
