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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-05-12</periodOfReport>

    <issuer>
        <issuerCik>0001622577</issuerCik>
        <issuerName>Arowana Inc.</issuerName>
        <issuerTradingSymbol>ARWA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001641004</rptOwnerCik>
            <rptOwnerName>Kwan Kien Khan</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O AROWANA INC.</rptOwnerStreet1>
            <rptOwnerStreet2>LEVEL 11, 153 WALKER STREET</rptOwnerStreet2>
            <rptOwnerCity>NORTH SYDNEY</rptOwnerCity>
            <rptOwnerState>C3</rptOwnerState>
            <rptOwnerZipCode>NSW 2060</rptOwnerZipCode>
            <rptOwnerStateDescription>AUSTRALIA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Ordinary Shares</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>25554</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Ordinary Shares</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2015-05-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>642</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.00</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6043</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Right to Receive Ordinary Share</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F3"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2015-05-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>642</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.00</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Ordinary Share</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>64</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6043</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Redeemable Warrant</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F5"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2015-05-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>642</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.00</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F6"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F7"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Ordinary Share</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>321</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6043</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Represents securities underlying units of the Issuer (&quot;Unit&quot;). Each Unit consists of one ordinary share, one right (&quot;Right&quot;) to receive one-tenth of one ordinary share upon the consummation of the Issuer's initial business combination and one redeemable warrant (&quot;Warrant&quot;) entitling the holder to purchase one-half of one ordinary share.</footnote>
        <footnote id="F2">Represents the price for which 642 Units were purchased, which price includes consideration for the underlying Ordinary Shares, Rights and Warrants. The Reporting Person irrevocably committed to purchase such Units prior to the effective date of the registration statement relating to the Issuer's initial public offering.</footnote>
        <footnote id="F3">Each Right entitles the holder to receive one-tenth (1/10) of one ordinary share upon consummation of the Issuer's initial business combination.</footnote>
        <footnote id="F4">If the Issuer fails to consummate an initial business combination within eighteen (18) months from the closing of the Issuer's initial public offering, the Issuer will be dissolved and the Rights will expire worthless.</footnote>
        <footnote id="F5">Each Warrant entitles the holder thereof to purchase one-half of one ordinary share at a price of $12.50 per full share, exercisable in multiples of two.</footnote>
        <footnote id="F6">Each Warrant will become exercisable on the later of the completion of an initial business combination and April 30, 2016.</footnote>
        <footnote id="F7">Each Warrant will expire five years after the completion of an initial business combination, or earlier upon redemption.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Kien Khan Kwan</signatureName>
        <signatureDate>2015-05-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
