Most Brits who contemplate taking on Portuguese citizenship don’t want to give up their British nationality so the good news is that Portugal permits dual nationality and you can keep your British passport. Other countries, e.g. Spain, do not permit a person to have dual nationality.
Several reasons for taking on Portuguese nationality:
• Lifelong access to state healthcare. Amongst retired UK expats across Europe, access to state healthcare is the most cited reason to move back to the UK.
• Should you become mentally or physically incapacitated you will not have the worry of reapplying for a UK passport or Portuguese permanent residency, both of which only last for 10 years.
• Certainty regarding your status in an EU country after Brexit.
• The ability to move around Europe unhindered after Brexit and enjoy all the benefits of being an EU citizen.
• Being able to vote in national elections.
At the time of writing, (Feb, 2017) there is no agreement in place regarding our future rights when the UK leaves the EU.
Any UK citizen aged 18 or over may apply for naturalisation as a citizen of Portugal once they have resided legally for six or more years in the country. Currently, as an EU citizen, this will require first having the 5 year EU temporary residency from your local Câmara and then applying for permanent residency from your local SEF (O Serviço de Estrangeiros e Fronteiras) office.
NOTE: EU citizens are not required to sit the language test for permanent residency but non-EU citizens are. This means that once the UK departs from the EU, Britons will become non-EU citizens and are likely to be treated as such so if you are considering taking out Portuguese permanent residency do it ASAP and before Brexit.
Citizenship is handled by the IRN (Instituto dos Registos e do Notariado) and advice can be sought from the local Conservatória. However, depending on where you live, you may find that you are the first person to ask and you may not get very far. I found this at my local Conservatória in Ourique, and whilst they were very friendly all they could do was to point me at the IRN website (see link below).
There are a variety of individual situations and therefore there are different forms from which to choose on the IRN website. All are in Portuguese only - visit:
https://irn.justica.gov.pt/Impressos-e-Modelos
You will need to prove you have sufficient command of the language so see HERE for the detailed information on the language test.
HERE is copy of a test paper sent to me before I did my test. No answers I'm afraid but at least anyone can see the standard required.
You must provide a certificate of your criminal record both from the UK and in Portugal. For the UK record you can apply online via:
https://www.acro.police.uk/police_certificates.aspx
Choose the ‘Police Certificates’ tab. Cost £45. It should take around 2 weeks and is sent by first class post.
For Portugal you need to go to your local Tribunal with either your passport or residencia. The cost is 5 euros and it takes around a week.
NOTE: Police record checks are only valid if issued within the 6-months prior to your application. The Portuguese check is only valid for 3-months. Therefore the advice is not to apply for either before you have had the results of your language test, just in case you fail.
Naturalisation by marriage
If you are married to a Portuguese citizen you may obtain Portuguese citizenship after three years as long as you make your declaration while you remain married. If you divorce or the marriage is annulled at a later date your Portuguese citizenship will not be rescinded.
My solicitor explained to me that the three year rule is to ensure that the relationship is stable and is to prevent marriages of convenience to gain citizenship. In the case of two Brits married for longer than three years, only one partner needs to apply and do the language test as the other can apply without the language test as soon as the former has acquired citizenship. There is a different form for this partner. At the time of writing the form is Modelo 3.
Unmarried partners
If you are in a relationship with a Portuguese citizen but not married, you may still obtain citizenship on the basis that you are in a de facto union as long as the union has been officially recognised by a civil court.
There is no required residence period for obtaining citizenship in this way, but you may be required to take Portuguese language test and show integration into Portuguese society.
All documents in English need to be translated into Portuguese and certified.
A payment of €250 must be made by cheque in euros and must be verified by your Portuguese bank (cheque visado). Ask for this at the counter of your local branch.
Once you have all the paperwork assembled and checked (I used a Portuguese solicitor), you should deliver it or post by registered mail to:
Conservatória dos Registos Centrais
Rua Rodrigo da Fonseca, 200
1099-003 Lisboa
Or:
Visit the following Conservatórias do Registo Civil:
Almada, Amadora, Aveiro, Barreiro, Braga, Coimbra, Évora, Faro, Guimarães, Lisboa, Mangualde, Ovar, Pombal, Ponta Delgada, Portalegre, Arquivo Central do Porto, Santarém, Silves, Tondela, Torres Vedras.
The process takes around 3-6 months.
Good luck!
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See also: 'Are you legal in Portugal? Rules on residency for citizens of the EU, EEA and Switzerland'