The Número de Identificação da Segurança Social (NISS) is Portugal's Social Security Identification Number. It identifies individuals within the Portuguese Social Security system and is used for matters such as social security contributions and access to applicable benefits. It is particularly relevant for people working in Portugal, including foreign nationals who need to register with Social Security.
Foreign nationals can apply for a NISS regardless of whether they are EU/EEA/Swiss citizens or citizens of other countries, provided they meet the applicable requirements. Depending on your nationality and circumstances, you may need to provide:
Important: You may also need to provide documents explaining why you need a NISS, such as proof of employment or self-employment. Additional immigration-related documentation may be required, depending on your situation.
The documents depend on your nationality and the reason for your application. They may include:
For third-country nationals, the current Social Security guidance also requires specific documentation concerning their residence or immigration application, subject to the applicable exceptions.
Before submitting your application, check the official checklist to ensure you have the documents required for your individual case.
Foreign nationals who meet the relevant conditions may also be eligible to request a NISS, Portuguese Tax Identification Number (NIF) and National Health Service User Number (NNU) together at certain designated service points.
Be cautious **of **fraudulent SMS messages, emails and websites impersonating Portuguese Social Security. Never click suspicious links or provide bank card details in response to an unexpected message claiming that you are entitled to receive money or benefits.
Find answers to common questions about this service.
Yes, if you are working in Portugal and need to be registered with Social Security, a NISS is generally required. Your employer is responsible for communicating the employment relationship to Social Security.
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