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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-06-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001215403</rptOwnerCik>
            <rptOwnerName>PAULSEN WILLIAM F</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>2008-06-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2000</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Restricted stock units awarded pursuant to the Issuer's 2005 Long - Term Incentive Plan (the &quot;Plan&quot;) that vest over time and are to be settled in common stcok (&quot;Common Stock&quot;) of Crystal River Capital, Inc. (the &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. All 2000 of such restricted stock units vest on June 10, 2009.</footnote>
        <footnote id="F2">Represents grant of restricted stock units pursuant to the Plan.</footnote>
        <footnote id="F3">Excludes 15,745 shares of Common Stock owned by The Paulsen Foundation, for which the Reporting Person serves as president and in which the Reporting Person has no pecuniary interest. Excludes 15,479 deferred stock units awarded pursuant to the Plan, which deferred stock units are to be settled in Issuer Common Stock on a one-for-one basis on the date on which the Reporting Person ceases to be a director of the Issuer.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ John J. Feeney, Jr., on behalf of William F. Paulsen</signatureName>
        <signatureDate>2008-06-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
