Becoming a citizen of Portugal: residence and dual nationality

For many Americans who settle in Portugal, citizenship is the long-term goal: an EU passport, the right to live and work anywhere in the EU, and no more permit renewals. The rules changed in 2026. This guide covers what the current nationality law requires of a US citizen who naturalizes through residence, and how US law treats dual nationality.

The 2026 change to the nationality law

Portugal's Ministry of Justice announced that changes to the Nationality Law entered into force on 19 May 2026. The amending law is Organic Law 1/2026 of 18 May, published in the Diário da República and corrected by Rectification Declaration 17/2026.

Two points from the Ministry's announcement matter most for anyone planning ahead:

• the new rules apply only to applications filed after the law entered into force;
• the law tightens the requirements for naturalization and changes the minimum period of legal residence.

If you filed an application before 19 May 2026, the earlier rules govern it. Anyone filing now applies under the new law.

How many years of residence

Under the amended law, the minimum period of legal residence in Portugal to apply for naturalization is:

• seven years for nationals of Portuguese-speaking countries or EU member states;
• ten years for nationals of other countries.

US citizens fall in the second group, so the requirement for an American is ten years of legal residence. The text of Organic Law 1/2026 adds that, for nationals of other countries, periods of legal residence can be added together as long as they fall within a maximum window of twelve years. A gap in residence does not automatically reset the count, but the years have to fit inside that window.

What counts is legal residence: time on residence permits issued by AIMA. Visitor time under the Schengen 90/180 rule does not count.

The new requirements

According to the Ministry of Justice, Article 6(1) of the Nationality Law now requires applicants for naturalization to show:

• sufficient knowledge of Portuguese culture, national history and national symbols;
• knowledge of the fundamental rights and duties of Portuguese nationality and of the political organisation of the Portuguese state;
• a solemn declaration of adherence to the fundamental principles of the democratic rule of law;
• no effective prison sentence of more than three years for terrorism, violent or especially violent crime, highly organised crime, crimes against state security, or assisting illegal immigration;
• no restrictive measures adopted by the United Nations or the European Union against the applicant.

The law also requires the ability to support yourself. These sit alongside the long-standing requirement of sufficient knowledge of the Portuguese language.

Documents for the application

The application form for naturalization of adults published by IRN, the Institute of Registries and Notaries, lists supporting documents including:

• a birth certificate, legalised where required, with translation if not in Portuguese;
• proof of knowledge of the Portuguese language and the other required knowledge;
• criminal record certificates from the country of birth, the country or countries of nationality, and any countries where you lived after age 16;
• a certified copy of your identification document.

For an American, that means a US birth certificate, an FBI Identity History Summary, and records from any other country you lived in as an adult. Ask IRN how it wants each document legalised and translated, and check that criminal records are recent enough when you file.

Language preparation

Portuguese language skills are both a legal requirement and the thing that makes ten years of residence livable. Starting early pays off: by the time you are eligible to file, everyday Portuguese should be routine rather than a test you cram for. Our guide to learning Portuguese covers courses and exams.

Dual nationality: the Portuguese side

The Ministry of Justice's guide to Portuguese nationality states that Portuguese law allows a Portuguese citizen to hold other nationalities, so you do not need to give up another nationality to acquire Portuguese nationality. It adds that other countries' laws may require you to give up Portuguese nationality to hold theirs.

Dual nationality: the US side

The US State Department explains that US law does not mention dual nationality or require a person to choose one citizenship. It also sets out the point that matters for naturalization abroad: a US citizen who applies for a foreign nationality can lose US citizenship only if they apply voluntarily, by free choice, and with the intention of giving up US citizenship. Intent can be shown by statements or conduct.

Practical consequences the State Department lists for dual nationals:

• you owe allegiance to both countries and must obey the laws of both;
• most US citizens, including dual nationals, must use a US passport to enter and leave the United States;
• the other country may require you to use its passport to enter and leave it, and using that passport does not endanger US citizenship;
• dual nationality can limit the US government's ability to help you while you are in the other country.

Becoming Portuguese also does not change your US tax position. US citizens are taxed on worldwide income wherever they live, and FBAR and Form 8938 reporting continue.

Planning the ten years

• Keep every permit current. A lapse in legal status is time that does not count.
• Keep copies. Save each residence card, renewal receipt and AIMA letter. You will need to prove your history.
• Track time abroad. Long periods outside Portugal can raise questions about whether you were actually resident.
• Start language study early and keep records of courses and certificates.
• Collect US documents in advance. Order a certified birth certificate and plan the FBI check close to filing.

Other routes

The new law also changes routes not based on residence. The Ministry of Justice says it ended the special regime for descendants of Sephardic Jews, removed some routes by descent, and extended nationality by descent to great-grandchildren of Portuguese-born citizens. If you have Portuguese ancestry or a Portuguese spouse, read the Ministry's guide, which organises the routes by profile.

Common questions

How many years does an American need to live in Portugal to naturalize? Ten years of legal residence under the law in force since 19 May 2026. The seven-year period applies to nationals of Portuguese-speaking countries and EU member states.

Do I have to give up US citizenship to become Portuguese? No. The Ministry of Justice says Portuguese law allows multiple nationalities. The State Department says a US citizen loses US citizenship only by applying for a foreign nationality voluntarily and with the intention of giving up US citizenship.

Does the new law apply to applications filed before May 2026? No. The Ministry of Justice states that the new provisions apply only to applications filed after the law entered into force on 19 May 2026.

Which passport do I use when flying to the US as a dual national? The State Department says most US citizens, including dual nationals, must use a US passport to enter and leave the United States.

What if I leave Portugal for a few years in the middle? Organic Law 1/2026 allows periods of legal residence to be added together for nationals of countries outside the Portuguese-speaking world and the EU, as long as they fall within a maximum window of twelve years. Time spent outside Portugal without a valid residence title does not count toward the ten years.

Does becoming Portuguese change my US tax filing? No. US citizens are taxed on worldwide income wherever they live, so the annual US return and foreign account reporting such as FBAR continue after you naturalize.