NISS Number Portugal | Social Security Number for Expats | Visas.pt

The NISS (Número de Identificação da Segurança Social — Social Security Identification Number) is assigned by the Instituto da Segurança Social (ISS — Social Security Institute) and is required for anyone who works, is self-employed, or makes social security contributions in Portugal.

When you need a NISS:

• Taking up employment with a Portuguese employer
• Registering as self-employed (trabalhador independente)
• Accessing SNS healthcare services as a contributing resident
• Applying for Portuguese citizenship (NISS is required as part of the naturalisation file)

When you do NOT immediately need a NISS:

• D7 visa holders who are retired and have no Portuguese employment
• D8 visa holders who work entirely for foreign employers (though some apply anyway for completeness)

The NISS is different from the NIF:

• NIF = tax ID (for financial and legal activity)
• NISS = social security number (for employment and contributions)

Most people need the NIF immediately; the NISS is needed when you start working or need it for citizenship. Visas.pt obtains NISS numbers for €140.