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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-10-20</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000350077</issuerCik>
        <issuerName>WMS INDUSTRIES INC /DE/</issuerName>
        <issuerTradingSymbol>wms</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001204726</rptOwnerCik>
            <rptOwnerName>REDSTONE SUMNER M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity></rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2005-10-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>100000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>25.42</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>100000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3483900</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By National Amusements, Inc.</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7900</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Spouse</value>
                    <footnoteId id="F6"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Share Forward Transaction</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-10-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>X</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F4"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>0.167</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>33.29</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F5"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>100000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">This Report on Form 4 relates to the partial settlement of a share forward transaction (the &quot;Forward Transaction&quot;) that the Reporting Person entered into on June 29, 2004 (the &quot;Trade Date&quot;) with an unrelated third party (the &quot;Buyer&quot;) and with respect to which the Reporting Person filed a Form 4 with the SEC on July 1, 2004. The Forward Transaction covered an aggregate of 600,000 shares of the Issuer and is to be settled in 6 equal tranches, each relating to 100,000 shares (each such amount, the &quot;Reference Amount&quot; for the relevant settlement date). The Forward Transaction specifies a &quot;Contingency Price&quot; of $33.29 per share and a &quot;Forward Floor Price&quot; of $21.62 per share. On each settlement date, the Reporting Person, unless he has elected cash settlement as described in the following sentence, will deliver to Buyer: (i) if the &quot;Settlement Price&quot; (a market-based price as determined under the terms of the Forward Transaction) for such settlement date is greater than the</footnote>
        <footnote id="F2">Contingency Price, a number of shares equal to the Reference Amount; and (ii) if the Settlement Price is less than or equal to the Contingency Price, a number of shares equal to the Reference Amount plus an additional number of shares (the &quot;Contingently Cash-Settled Delivery Amount&quot;) equal to (a) the Reference Amount multiplied by (b) the lesser of (x) the Contingency Price minus the Settlement Price and (y) the excess of the Contingency Price over the Forward Floor Price, divided by (c) the Settlement Price (except that if the Settlement Price is less than or equal to $10.00, the Reporting Person shall deliver the Reference Amount of shares and make a cash payment to the Buyer in respect of the Contingently Cash-Settled Delivery Amount). In lieu of delivering shares, the Reporting Person may elect cash settlement for any tranche. The Reporting Person received a prepayment from Buyer in the amount of $19,974,000 within 3 business days of the Trade Date, which proceeds the</footnote>
        <footnote id="F3">Reporting Person used for investment purposes. Pursuant to the foregoing arrangements, the Reporting Person will deliver to the Buyer 100,000 shares of Common Stock and to make a cash payment of $787,000 within 3 business days of October 20,2005, in connection with the settlement of the sixth tranche of the Forward Transaction. As a result of the above transation, codes S and K also apply to the transaction reported herein</footnote>
        <footnote id="F4">Transaction Code K also applies to this transaction reported herein.</footnote>
        <footnote id="F5">The Transaction will be settled in six equal tranches of 100,000 shares of Common Stock three business days after each of the following: September 8, 2005, September 15, 2005, September 22, 2005, October 6, 2005, October 13, 2005 and October 20, 2005.</footnote>
        <footnote id="F6">Reporting Person(RP) disclaims beneficial Ownership of 7,900 shares owned by his wife at time of marriage. This report shall not be deemed an admission that RP is beneficial owner of such securities for purposes of Section 16 or for any other reasons</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Tad Jankowski, Attorney in Fact for Sumner M.Redstone Power of Attorney</signatureName>
        <signatureDate>2005-10-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
