Updated on: 08-01-2025

Registration

Allocation of a Portuguese Social Security Identification Number (NISS)

What is the Social Security Identification Number (NISS)?

The Social Security Identification Number (NISS) is the number that allows a unique, precise and accurate identification of citizens towards the Social Security system, at national level.

Request for a Social Security Identification Number (NISS) – Foreign Citizens and National Citizens who are not required to have a Citizen Card

The Social Security Identification Number (NISS) is automatically allocated to national citizens when they apply for the Citizen Card.

The request for the allocation of a Social Security Identification Number (NISS) to a foreign citizen or a national citizen who is not required to have a citizen card is submitted by completing the online form available here: Pedido de NISS – Cidadão Estrangeiro ou Cidadão Nacional sem obrigatoriedade de ter cartão de cidadão (Request for a Social Security Identification Number (NISS) – Foreign Citizens and National Citizens who are not required to have a Citizen Card).

How is the Social Security Identification Number (NISS) allocated to Legal Persons?

The request for the allocation of a Social Security Identification Number to legal persons (registration in the Social Security system) is made automatically to the Social Security Institute whenever the legal persons (companies) are created online.

When the legal persons (companies) are registered at the commercial registry offices, this fact is communicated ex officio, electronically and free of charge by the commercial registry offices to the Social Security Institute.

The legal persons registration is mandatory and it is communicated ex officio through automatic data transmission by the Tax and Customs Authority (AT) to Social Security, on the date of:

the activity beginning communication;
the creation of companies/associations under the special scheme for the immediate creation of companies and associations, the online creation of companies, or the immediate creation of permanent representations of foreign entities;
communication by the registry offices of the employers registered under the commercial scheme and of the employers included in the central registry of companies, in the case of entities not subject to mandatory commercial registration;
admission of the first worker, in the case of natural persons who benefit from the professional activity of third parties, carried out under an employment contract;
the inspection and supervision activities (in the case of entities created without official registration, with workers at their service).

For further information on the allocation of a Social Security Identification Number (NISS) to legal persons, please see the Practical Guide – Registration and Change of Data – Legal Person.

How is the Social Security Identification Number (NISS) allocated to Natural Persons?

NATIONAL CITIZENS WITH A CITIZEN CARD

The Social Security Identification Number (NISS) is automatically allocated to national citizens when they apply for the Citizen Card.

FOREIGN CITIZENS AND NATIONAL CITIZENS WHO ARE NOT REQUIRED TO HAVE A CITIZEN CARD

The request for the allocation of a Social Security Identification Number (NISS) to a foreign citizen or a national citizen who is not required to have a citizen card is made through an online form available on the Social Security Portal; in the Sou Cidadão (I am a Citizen) menu, click on Atribuição de Número de Identificação de Segurança Social (NISS) (Allocation of Social Security Identification Number – NISS) > Formulário para pedido de Número de Identificação de Segurança Social (Social Security Identification Number application form).

Please note: When the application is submitted by the Employer, it is exclusively aimed to the allocation of a Social Security Identification Number to the foreign citizen, being the Employer required to communicate the worker's employment relationship, through the Social Security Online Service (SSD – Segurança Social Direta).

Necessary documents for the NISS application submission by the applicant himself/herself (foreign citizen or national citizen who is not required to have a citizen card)

Copy of the civil identification document of the applicant, valid at the time of the application submission. The accepted ID documents are the following:

In the case of a national citizen without a citizen card, he/she must submit a valid ID card
In the case of a foreign citizen from a third country, i.e., countries that are not members of the European Union (EU) or of the European Economic Area (EEA) - Any country not bound to Portugal by an international agreement or convention on the coordination of social security systems:
- Simple copy of the Passport, or
- Residence Permit, Authorization (Temporary/Permanent)

(simple copies of the documents, whether the application is submitted by the citizen or a legal representative on his/her behalf).

Please note: In accordance with Article 84 of Law no. 23/2007, the residence permit shall replace, for all legal purposes, the ID document, without prejudice to the arrangements provided for by the Treaty of Friendship, Cooperation and Consultation between the Portuguese Republic and the Federative Republic of Brazil, signed in Porto Seguro on 22 April 2000.

In the case of a foreign citizen of another EU/EEA Member State or Switzerland, one of the following documents must be attached to the form:
- Civil identification document of the country of origin, or
- Passport, or
- Residence card.

(simple copies of the documents, whether the application is submitted by the citizen or a legal representative on his/her behalf).

In the case of citizens covered by International Protection (outside the scope of Temporary Protection – Ukraine) and in the case of citizens who do not have another ID document, the following documents shall be considered for identification purposes:
- Proof of the application submission for a temporary residence permit; temporary residence permit; proof of the temporary residence permit extension; proof of residence permit/subsidiary protection granting - refugee; residence permit/subsidiary protection - refugee; proof of the residence permit extension – refugee; proof of the residence permit/subsidiary protection extension; statement of international protection.

Documentary evidence of the reason for the NISS application

In accordance with Article 99 of the Social Security Framework Law as amended, and for the purposes of the Social Security Identification Number (NISS) allocation, in the Documento de Identificação (Identification Document) field, please insert, in a single file, your ID document and the documents required to assess your application:

proof of employment status:
- employment contract (employees or domestic service workers) - (translated into Portuguese), or
- copy of the document attesting the self-employment activity beginning and copy of the receipts/invoices (self-employed persons), or
- company registration certificate issued by the Institute of Registries and Notary (IRN) - permanent commercial certificate (Members of Statutory Bodies), or
- proof of an employment contract with a foreign Employer in the case of Digital Nomads, or
- document attesting that the person concerned is entitled to be covered by the Voluntary Social Insurance Scheme.

Documents required for the application examination

In the case of a foreign citizen from a third country, one of the following documents must be attached to the form:

Residence Permit/Authorization (Temporary/Permanent).
Short-stay visa/temporary stay for seasonal work;
Work/residence visa, such as:
- Residence visa for the exercise of subordinate professional activity;
- Residence visa for self-employed persons or immigrant entrepreneurs;
- Residence visa for teaching, highly qualified or cultural activities;
- Residence visa for highly qualified activities carried out by a subordinate worker;
- Residence visa for professional activities provided remotely for entities outside the national territory;
- Residence visa for research, studies, exchange of secondary school students, internships and voluntary work;
- Residence visa for the purpose of family reunification;
- Temporary stay visa for the transfer of workers;
- Visa for job search;

Proof of application for:

Residence Permit/Authorization (Temporary/Permanent).
Residence Visa for citizens of the Community of Portuguese Speaking Countries (CPLP)
Residence Permit Certificate for citizens of the Community of Portuguese Speaking Countries (CPLP)

Please note: A foreign citizen who is qualified as a Member of Statutory Body (MOE) of a company identified in the Social Security Information System (SISS), and who is residing abroad, may not be required to submit any supporting documents of residence permit or visa application.

Additional documents required when the NISS application is submitted by the Employer or Legal Representative

Valid ID document of the legal representative;
Formal proof of the legal representation (power of attorney – original document);

Form PA-12 - Declaration of Authorisation to Third Parties, and copy of the valid identification document of the represented person.

All the necessary data for the identification of the person concerned (foreign citizen or national citizen who is not required to have a Citizen Card) in the Social Security System must be provided; more specifically, the data included in the application form, such as:

Full name;
Date of Birth;
Gender;
Marital status;
Country of birth;
Place of birth;
Nationality;
Type and number of Civil Identification Document;
Expiry date;
Taxpayer number (if already allocated);
Country of residence;
Address
Address (to be indicated only if the country of residence is ≠ PT);
Mobile phone number
Email
Attachments: copy of valid ID document of the legal representative and of the legal representation document or Form PA-12 - Declaration of Authorisation to Third Parties

NISS document collection by the foreign citizen or national citizen who is not required to have a Citizen Card

The NISS document collection is made by the person to whom the NISS was allocated, with submission of a valid ID document (identity card, passport, residence permit or other civil identification document).

The NISS document may also be delivered to a Lawyer who submits his/her professional certificate and an original power of attorney.

It may also be collected by a third party, provided that he/she submits an original power of attorney or form PA 12 and the respective ID document.

The notification/communication of the NISS allocation, informing that the respective document must be collected at a Social Security Customer Information Service (with prior appointment), is sent to the applicant's address stated in the Application Form, or to the address of the Legal Representative, by Registered Letter without Acknowledgment of Receipt.

In order to avoid queues, you can schedule your appointment to collect the NISS via the 210 548 888 or 300 088 888 Appointments Line, business days from 9:00 a.m. to 6:00 p.m.

Additional information on this theme is available in the Practical Guide – Request for a Social Security Identification Number (NISS) – Foreign Citizens and National Citizens who are not required to have a Citizen Card