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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-04-29</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001344705</issuerCik>
        <issuerName>Crystal River Capital, Inc.</issuerName>
        <issuerTradingSymbol>CRZ</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001294561</rptOwnerCik>
            <rptOwnerName>Salvatore Louis P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CRYSTAL RIVER CAPITAL, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>3 WFC, 200 VESEY STREET, 10TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10281-1010</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2008-04-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1226</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>14926</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Deferred stock units awarded pursuant to the Issuer's 2005 Long-Term Incentive Plan (the &quot;Plan&quot;) that are to be settled in common stock (&quot;Common Stock&quot;) of Crystal River Capital, Inc. (th &quot;Issuer&quot;) on a one-for-one basis in one installment that is issued on the date on which the Reporting Person ceases to be a director of the Issuer.</footnote>
        <footnote id="F2">Represents deferred stock units credited to the account of the Reporting Person which converts to shares of Common Stock of the Issuer on a one-for-one basis. The number of shares of Common Stock subject to the deferred stock units credited to the Reporting Person was determined by dividing (1) the product of the number of shares of Common Stock subject to all restricted stock units and deferred stock units held by the Reporting Person on March 31, 2008 and the per share dollar amount of the Common Stock dividend paid by the Issuer on April 29, 2008 by (2) the closing price of the Common Stock on the New York Stock Exchange on April 29, 2008.</footnote>
        <footnote id="F3">Excludes 10,000 shares of CommonStock owned by the Reporting Person. Excludes 2,000 restricted stock units awarded pursuant to the Plan that vest over time and are settled in Issuer deferred stock units upon vesting, which deferred stock units are to be settled in Issuer Common Stock on a one-for-one basis in one installment that is issued on the date on which the Reporting Person ceases to be a director of the Issuer. All 2,000 of such restricted stock units vest on June 12, 2008.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ John J. Feeney, Jr., on behalf of Louis P. Salvatore</signatureName>
        <signatureDate>2008-05-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
