Apply for a Social Security Identification Number (NISS)

You can apply for the NISS by filling in the form available on the Social Security website. You must attach the valid civil identification documents to the form, as required.

Foreign nationals

Foreign nationals must submit three types of document: ID, work status and proof of residence permit.

• Citizens of the European Union, the European Economic Area or Switzerland must submit one of the following documents (valid and scanned):
  • national identification document from your country of origin and an uncertified copy thereof;
  • passport;
  •  residence card.
• Persons from third countries must submit all of the following documents:
  •  passport;
  • work visa;
  • residence permit (temporary or permanent) or other civil identification document from their country of origin.
• Persons covered by international protection (not including temporary protection for persons coming from Ukraine) or without any other identification document may present one of the following documents:
  • provisional residence permit (ARP)
  • proof of an application for an ARP
  • proof of renewal of an ARP
  • refugee residence permit – subsidiary protection
  • proof of the granting of a refugee or subsidiary protection residence permit
  • proof of renewal of a refugee residence permit
  • proof of renewal of a residence permit – subsidiary protection
  • declaration of international protection.

Documents relating to the reason for being assigned an NISS

Proof of employment status

Foreign nationals must provide one of the following pieces of evidence of their employment situation:

• employment contract
• copy of registration as self-employed and copy of receipts/invoices
• company registration certificate from the Institute of Registries and Notaries (IRN)
• permanent trading certificate (MOE)
• proof of employment contract with an EEA company in the case of digital nomads
• proof of eligibility for registration for voluntary Social Security contributions (SSV).

Proof of residence permit

Foreign nationals must provide one of the following pieces of evidence of their application for residence:

• proof of application for a residence permit
• proof of application for a residence visa for citizens of the Community of Portuguese Language Countries (CPLP)
• proof of application for a residence authorisation certificate for CPLP citizens.

Application by the employer or legal representative of the foreign national

The following must be submitted:

• a power of attorney (original document) or Declaration of authorisation for third parties – PA12;
• valid civil identification document of the legal representative (passport, work visa, residence permit or other civil identification document from the country of origin).

The employer acts as the employee’s legal representative. This application is intended solely for the assignation of an NISS. Employers must report their employee’s employment relationship on Social Security Direct (SSD).

Portuguese nationals without a Citizen Card

Copy of their lifetime ID card.

Portuguese nationals with a Citizen Card

The NISS is assigned to persons with Portuguese citizenship when the Citizen Card is requested.

It is free of charge.

After the request for the NISS is submitted, it will be analyzed by the Social Security services, and there is no set deadline for the NISS to be assigned.