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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2025-03-31</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000351834</issuerCik>
        <issuerName>SunOpta Inc.</issuerName>
        <issuerTradingSymbol>STKL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002062282</rptOwnerCik>
            <rptOwnerName>McCullough Christopher</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>7078 SHADY OAK ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>EDEN PRAIRIE</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55344</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>General Counsel</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Shares</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4962</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Performance Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.00</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Shares</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>8910</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.00</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Shares</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2970</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.00</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Shares</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5497</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>6.35</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2023-07-10</value>
                <footnoteId id="F6"/>
            </exerciseDate>
            <expirationDate>
                <value>2033-07-10</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Shares</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>7756</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>6.55</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2034-04-30</value>
                <footnoteId id="F7"/>
            </exerciseDate>
            <expirationDate>
                <value>2034-04-29</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Shares</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>8528</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The Performance Stock Units (&quot;PSUs&quot;) will vest or expire on April 15, 2026 (&quot;Vesting Date&quot;), depending on the Company's total shareholder return (&quot;TSR&quot;) performance relative to the Russell 3000 Food and Beverage companies during the performance period as described in the award agreement. If none of the hurdles are met, none of the PSUs will vest and the award will expire. If the 25th percentile hurdle is met, 25% of the PSUs will vest. If the 50th percentile hurdle is met, 100% of the PSUs will vest. If the 75th percentile hurdle is met, 125% of the PSUs will vest. If the 90th percentile or above is met, 200% of the PSUs will vest. The number included in column 3 of Table II reflects the target number of PSUs eligible for vesting subject to the reporting person's continued employment with the Company through the Vesting Date.</footnote>
        <footnote id="F2">The Performance Stock Units do not have an expiration date.</footnote>
        <footnote id="F3">The Restricted Stock Units vest in three equal annual installments beginning on July 10, 2024, subject to the continued employment of the reporting person through each such vesting date.</footnote>
        <footnote id="F4">The Restricted Stock Units do not have an expiration date.</footnote>
        <footnote id="F5">The Restricted Stock Units vest in three equal annual installments beginning on April 30, 2025, subject to the continued employment of the reporting person through each such vesting date.</footnote>
        <footnote id="F6">The Stock Options vest in three equal annual installments beginning on July 10, 2024, subject to the continued employment of the reporting person through each such vesting date. These options qualify as incentive stock options.</footnote>
        <footnote id="F7">The Stock Options vest in three equal annual installments beginning on April 30, 2025, subject to the continued employment of the reporting person through each such vesting date. These options qualify as incentive stock options.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Chris McCullough</signatureName>
        <signatureDate>2025-04-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
