If you are a national of a European Union country, Iceland, Liechtenstein, Norway or Switzerland and you remain in Portugal for a period of more than three months, you must request a Registration Certificate (Certificado de Registo) from the City Council of your area of residence. This document formalises your right to reside in Portugal.
After you have held a registration certificate for five consecutive years, you may request a Permanent Residence Certificate (Certificado de Residência Permanente) from the Foreigners and Borders Service (Serviço de Estrageiros e Fronteiras). Contact the Foreigners and Borders Service for more details about the requirements necessary for making this request.
If you are a citizen of a third state (all other situations), and you wish to become resident in Portugal, you must hold a residency visa that is suitable for the purpose of your stay. This visa allows you to enter Portuguese territory for the purpose of requesting a residence permit from the Foreigners and Borders Service.
Notwithstanding any special legal provisions that may apply, the temporary residence permit is valid for a period of one year from the date on which the document is issued. It may be renewed for successive two year periods. After five years of temporary residence, holders of this document may request a permanent residency permit.
Please note that you must make an appointment before going to one of the offices of the Foreigners and Borders Service, either over the phone or through its website.
THIS INFORMATION IS NOT INTENDED TO BE A SUBSTITUTE FOR CONSULTING THE APPLICABLE LEGISLATION
Source: Ministry of Foreign Affairs - Directorate General of Consular Affairs and Portuguese Communities