How to Get a NISS for a Baby Born in Portugal (Foreign Parents)

Many immigrant parents are asking how to get a Social Security number (NISS) for a baby born in Portugal, and some say they were turned away at the counter. The answer depends first on one question: is your baby Portuguese or foreign?

What’s happening

Since 19 May 2026, under article 1 of the Nationality Law as amended by Lei Orgânica 1/2026, a child born in Portugal to foreign parents is Portuguese from birth in three cases: a parent was also born in Portugal and lived here at the time of the birth, with or without a residence permit; it is declared that the child wants to be Portuguese and, at the time of birth, one parent had lived legally in Portugal for at least five years (this does not apply if the parents are here in the service of their own country); or the child has no other nationality. In the five-year case, that parent’s ID and a valid residence document are shown when the declaration is made.

Portuguese baby: at a hospital with a Nascer Cidadão desk you can register the birth and request the first Citizen Card, free. When the first card is requested, the NIF, NISS and SNS number are assigned automatically. No separate NISS request.
Foreign baby: the birth is still registered in Portugal (free; at the hospital, online or at a civil registry within 20 days), but the NISS must be requested separately.

What it means for a foreign baby

Social Security’s practical guide on NISS for foreigners (v1.18) says the request is made online only, on seg-social.pt under Ajuda → Número de Identificação de Segurança Social (NISS) → Atribuição de Número de Identificação de Segurança Social (NISS), then Pedido do NISS. A parent applies as the child’s legal representative. A NISS needs a link to Social Security; for a child, that is usually a benefit such as abono de família. The guide asks for:

a signed declaration (compromisso de honra) explaining why the NISS is needed and for which support;
ID of the person applying and of those with parental responsibility;
proof of the residence-permit application of the parents and of the child. For abono de família, the parents’ application receipt alone can be enough. If the parents’ permit is already approved, send proof of that approval;
if no Social Security benefit is involved, a declaration from the body that needs the NISS (for example, a school).

Parents’ residence still pending? The guide accepts proof that a residence application was made. Separately, the baby’s own residence permit is requested through AIMA’s contact form, under Autorização de Residência → Pedido agendamento Bebés/menores estrangeiros nascidos Portugal – Art. 124. AIMA’s notice of 18 May 2026 (republished by the Ordem dos Solicitadores e dos Agentes de Execução) says this route is for children of parents who hold a residence permit. Under article 124 of the Foreigners Law, a parent must apply within six months of the birth registration. AIMA does not say what applies while a parent’s permit is pending. Our AIMA email writer can help you prepare the request.

No passport yet? For the NIF, the AT accepts a birth document plus proof of address for foreign children born here with resident status. The Social Security guide does not say how a baby with no passport or residence card is identified, so confirm with Social Security. The joint NIF/NISS/SNS service, offered for now at 12 Espaços Cidadão, needs the passport (or EU ID card) of the person the numbers are for, and a child must be present, so it may not work for a baby without a passport.

What to do

Register the birth before the mother leaves hospital, or within 20 days.
If a parent was also born in Portugal and lived here at the birth, or one parent had 5+ years’ legal residence at the birth, ask the registry whether your baby is Portuguese (in the five-year case, a declaration is needed).
Otherwise, submit the online NISS form with the documents above and save the request ID.
Track it under Consulta do pedido de NISS (request ID, email and date of birth). Social Security’s guide says you get the NISS proof there after a biometric check or, if that check can’t be completed, through a video appointment booked by phone or at a Social Security office. It doesn’t say how this works for a baby. gov.pt’s NIF and NISS guide (updated 2 September 2026) instead describes a registered letter telling you to collect the NISS at a Social Security office, so follow the instructions you receive.
If a parent holds a residence permit, apply for the baby’s permit through AIMA’s contact form (Pedido agendamento Bebés/menores estrangeiros nascidos Portugal – Art. 124) within six months of the birth registration.

Key contacts

Linha Segurança Social: 210 545 400 / 300 502 502 (working days 9:00–18:00).
Appointments line: 210 548 888 / 300 088 888.
AIMA contact form: contactenos.aima.gov.pt.

Sources

This guide is general information, not legal advice. Last updated: 2 October 2026.

Featured image: Branded graphic: Link in Portugal (no third-party news photos)

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