Portuguese NISS Explained: Social Security Number for New Residents

The NISS is Portugal’s social security number, and unlike the tax number you cannot simply ask for one because you would like to have it. Portugal issues a NISS only where there is a reason — a job, self-employment, a benefit claim — and the request is made online, from anywhere, at no charge. What trips people up is the evidence of the reason, not the form.

Start with the thing that decides whether you need to do anything at all.

You may already have one

Since 2022, a Portuguese residence visa is issued together with a pré-autorização de residência. Article 58.º, paragraph 6 of Lei n.º 23/2007 provides that this document carries the provisional allocation of tax, social security and national health service numbers.

So if you are arriving on a D7 or remote-work residence visa, check what came with the visa before you request anything. If you are applying separately — because you are taking a job, going self-employed, or because AIMA has asked for a NISS before it will grant you a permit that allows work — read on. Where this sits in the wider move is set out on our Portugal residency service page.

What the NISS is, and who issues it

The Número de Identificação da Segurança Social is described on the official service page as “o número que permite aceder a direitos e cumprir deveres na Segurança Social” — the number that lets you access rights and meet obligations in the social security system. It is issued by the Instituto da Segurança Social, I.P.

The same page notes who does not need to request one: holders of a Portuguese citizen card and Portuguese companies, for whom it is allocated automatically. Foreign nationals, and Portuguese citizens with an old-style lifetime identity card, must ask.

You need a reason — officially, a link to social security

This is the substantive requirement and it is where a request fails if it fails. The Instituto da Segurança Social’s practical guide for foreign citizens (PDF, published 24 September 2025) puts it plainly: for a NISS to be allocated, “é necessário existir uma ligação à Segurança Social” — a link to social security must exist. It then lists what counts:

• An employment contract, as an employee
• Working on your own account, as a self-employed worker
• Being a member of a company’s statutory body
• Any other situation covered by the social security system
• Registration in the voluntary social insurance scheme
• Needing to receive support paid by social security

One consequence catches employees out. Where the link is a job, the guide states that the NISS is allocated only “se a entidade empregadora fizer primeiro um contrato de trabalho com a pessoa em causa” — only if the employer first makes an employment contract with the person. The contract comes before the number, not after it.

The legal basis given on both official sources is Lei n.º 4/2007 of 16 January (Article 99.º), Lei n.º 110/2009 of 16 September — the contributory code — and Decreto Regulamentar n.º 6/2018 of 2 July.

How the request is made: online only

There is no counter route. The Instituto da Segurança Social’s guide answers its own “where to apply” question with “Exclusivamente Online” — exclusively online — through the social security portal’s help menu. The form sits at the NISS request page on seg-social.pt, and that is the link the government service page itself points to.

The sequence, from the official guide:

1. Give an email address and confirm it by entering a code sent to it
2. Pass a “not a robot” check
3. Choose the Motivo — the reason — from a fixed list: professional activity for an employer, independent professional activity, claiming a social security benefit, claiming support through another body, or other
4. Upload the supporting documents
5. Complete the identification and address tabs, and submit

Upload limits are published: a maximum of 3 MB, in PNG, JPG or PDF. The address section accepts a country other than Portugal, so a Dubai address is not a problem in itself.

Progress can be tracked at the request-status page using the request ID, the email address used and the date of birth.

Documents for a third-country national

Here the two official sources differ in strictness, and you should know that before someone tells you one of them is wrong.

The Instituto da Segurança Social guide asks for one identity document — for third-country citizens, a copy of either the passport or the residence permit, temporary or permanent.

Separately, for the documents needed to analyse the request, it asks for one of a list that includes a residence permit, a short-stay or temporary-stay visa for seasonal work, a work or residence visa — and the enumerated options include the residence visa for employed work, the residence visa for working remotely for outside Portugal, the job-seeker visa and the digital nomad visa. That list is the useful part for anyone arriving on the remote-work route: the visa itself is named.

The gov.pt service page asks for all three — passport, work visa, and residence permit or another civil identity document from the country of origin — plus proof of the work situation and proof of the residence permit.

Proof of the reason, per the Instituto’s guide, is the employment contract translated into Portuguese, or the self-employment registration with invoices or receipts, or the company registry certificate, or — for digital nomads specifically — proof of an employment contract with a foreign employer, or the document establishing entitlement to voluntary social insurance.

The translation requirement is easy to miss and expensive to discover late. Our guide on attestation and translation of UAE documents covers how that is handled from this side.

A NIF is not listed as a requirement, but the form captures it, and where the reason chosen is independent professional activity the guide says the NIF must be entered in the identification tab. If you do not have one yet, our guide on getting a Portuguese NIF from Dubai deals with that first step.

Can you get a NISS before you have a residence permit?

Yes, and unusually this is addressed head-on in an official document rather than left to inference.

The Instituto’s guide has a section on exceptional situations for foreign citizens, covering the case where “a AIMA, I.P. … exige que a pessoa já tenha NISS atribuído pela Segurança Social para dar autorização de residência que permita trabalhar” — where AIMA requires a NISS to already have been allocated before it will grant a residence permit allowing work. It names job-seeker visa holders, student visa holders and temporary-stay visa holders as examples.

In those cases, where the applicant cannot produce a residence permit, proof of a residence application or proof of working, the guide says to attach instead the identity documents that apply, plus a declaration or request from AIMA explaining why the NISS is needed.

Read the boundary carefully, though. A qualifying visa, or an AIMA declaration, is what stands in for the permit. We found no official pathway for someone sitting in Dubai with no Portuguese visa and no AIMA involvement at all, and we are not going to invent one.

Cost and timing

It is free. The gov.pt service page answers its own cost question with “É gratuito”.

There is no published processing time, and that is an official position rather than an omission. The same page states: “Depois de submeter o pedido do NISS, o pedido será analisado pelos serviços da Segurança Social. Não existe um prazo definido para a Segurança Social atribuir o NISS.” No defined deadline. Any number of days you have been quoted did not come from Portugal.

On collecting the number, the service page describes a registered letter sent to the address you gave, telling you the NISS can be collected at a social security counter. The Instituto’s guide also describes an online route to obtain proof of the NISS, which requires biometric verification.

If you are already in Portugal, there is a combined service

Worth knowing, because it saves two separate processes. A single service issues the tax number, social security number and national health service user number together, free of charge, at a limited number of Espaços Cidadão. Its conditions are the catch: a Portuguese address, and either having applied for or already holding a residence permit, with authentication through a digital mobile key linked to a passport or European eID. It is for people who have landed, not for people preparing from the UAE.

How we usually handle this — our practice, not a rule

Marked as practice because no official page prescribes it.

We treat the NISS as a downstream step rather than a parallel one, and we do not open a request before the thing that justifies it exists, because the reason is what the request is judged on. Where the reason is employment, we wait for the signed contract and get the Portuguese translation arranged in the same movement rather than as an afterthought. Where a client is on a residence visa, we check what the pre-authorisation already contains before requesting anything, since duplicating a number that was already allocated creates work rather than saving it. And because there is no published processing time, we plan around the absence of one rather than around an estimate.

The step that usually follows all of this is the permit itself: we have a separate guide on the AIMA appointment and the residence permit.

What we could not verify

Two things. Several of the social security portal’s own landing pages for the NISS now redirect to the portal home rather than to content, so the durable official sources are the government service page and the Instituto’s practical guide, which is why we have leaned on those. And we found no official statement that a person with no Portuguese visa and no AIMA involvement can obtain a NISS from abroad; the exceptional route in the Instituto’s guide is built around a qualifying visa or an AIMA declaration.

Frequently asked questions

Can I get a NISS from outside Portugal?

The request itself is made online and the form accepts an address outside Portugal, so the mechanics do not require you to be there. What the request does require is a reason recognised by social security — an employment contract, self-employment, a benefit claim — and supporting documents, which for a third-country national means a passport or residence permit and, in the exceptional route, a qualifying visa or a declaration from AIMA.

Is there a fee for a NISS?

No. The official government service page states that requesting a NISS is free.

How long does a NISS take?

Portugal does not publish a processing time. The official service page states that there is no defined deadline for social security to allocate the number. We would treat any specific figure you have been given as an estimate from the person giving it rather than an official target.

Do I need a residence permit before I can request a NISS?

Not always. The Instituto da Segurança Social’s practical guide sets out an exceptional route for cases where AIMA requires the NISS before it will grant a residence permit that allows work, and in that route a qualifying visa plus a declaration or request from AIMA stands in for the permit. A passport alone, with no Portuguese visa and no AIMA involvement, is not a route we found in any official source.

Does my employment contract need translating?

Yes, where it is the proof of your reason for needing a NISS. The Instituto’s guide lists the employment contract as needing to be translated into Portuguese.

Is the NISS the same as the NIF?

No. The NIF is the tax number issued by the tax authority; the NISS is the social security number issued by the Instituto da Segurança Social. They are requested separately, through different bodies, and for different reasons — although a Portuguese residence visa now comes with both allocated provisionally.

My employer says they will get the NISS for me. Is that possible?

The government service page lists employers contracting a foreign national, and legal representatives acting in a foreign national’s name, among those who may make the request. Where a representative acts, the page asks for an original power of attorney or a third-party authorisation declaration, plus the representative’s own valid identity document.