Dual Citizenship in Portugal: Do You Have to Give Up the One You Have?
Portugal generally allows dual nationality. Becoming Portuguese does not carry a general requirement to renounce the nationality you already hold.
That answers the Portuguese side of the question. It does not answer what your other country will do. Before relying on a reassuring example from another family, separate those two legal systems.
Keeping another nationality is not the same as qualifying for Portugal's
The absence of a renunciation requirement does not create eligibility. You still need to satisfy the route through which you apply: a qualifying parent or grandparent, marriage, legal residence or another provision that actually fits your circumstances.
The 2026 amendment changed several eligibility conditions. It did not introduce a general rule that applicants must surrender their other nationality. Nor should a declaration of adherence to Portuguese democratic principles be confused with renunciation of another citizenship.
The other country's rules still matter
Some countries permit multiple nationality broadly. Others attach consequences to voluntary acquisition of a foreign nationality, distinguish nationality acquired at birth from naturalisation, or require a particular procedure before acquisition.
Those questions have to be checked under that country's current law. The answer can depend on how Portuguese nationality is acquired and on the person's age or circumstances. “Portugal allows it” cannot be used as a promise that another nationality will be retained.
Where advice in another jurisdiction is necessary, coordinate it before the legally significant step. Checking only after registration may leave the person trying to repair an avoidable problem.
Why an emigrant grandparent's history needs checking
Today's general acceptance of dual nationality does not prove that a grandparent retained Portuguese nationality under every historical legal regime. If a claim depends on that grandparent, investigate the nationality record and any relevant foreign naturalisation.
For the direct grandchild route, the law refers to a grandparent with Portuguese nationality of origin who did not lose it. A passport remembered by the family is useful background, but the record and the legal history are what establish the position.
Do not assume loss merely because the relative naturalised elsewhere. Do not assume retention merely because that would be the usual result today. The dates matter.
Your other nationality is not irrelevant to the file
Nationality, identity documents and countries of residence can affect the information or evidence required in an application. Differences between names on foreign records may also need to be reconciled. The fact that renunciation is not required does not make every other passport or foreign record immaterial.
The same distinction applies to travel. Which passport or identity document to present can be governed by the entry and exit rules of the countries involved. It is not simply a matter of choosing the more convenient passport at each airport.
What Portuguese nationality changes
Portuguese nationality brings citizenship of the European Union and the rights attached to it. Exercising residence rights in another Member State can still involve conditions and formalities. Nationality is not a blanket exemption from residence registration, tax rules or every requirement affecting family members.
Children's nationality also needs to be considered under the relevant route and family circumstances. It should not be promised that every future generation automatically receives every nationality held by the parent.
The practical sequence
Establish the Portuguese route. Check whether acquiring Portuguese nationality affects the other nationality under that country's law. Review the family and identity records, then organise the application around the rules that actually apply.
On the Portuguese side, there is no general exchange in which one passport must be surrendered to receive another. A reliable answer about keeping both comes from checking both countries, not from treating one country's answer as universal.
Describe the facts and relevant records to assess the next step.
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