If your child was born in Brazil and has a parent whose Portuguese citizenship is registered, the child can apply for Portuguese nationality by attribution under article 1(1)(c) of the Nationality Law. Before 18, this application has two advantages adults do not have: no IRN registration fee, and a priority review queue.
These advantages matter in practice. The difference in waiting time between minors and adults can be years. The earlier the application is filed, the sooner the child has the document. Since the nationality applies back to birth, there is no downside to registering early.
What the law requires for the child path
Paragraph (c) requires that the father or mother be Portuguese. They do not need to be Portuguese by origin, as on the grandchild path, but they must be registered as Portuguese. If the parent is entitled to Portuguese citizenship but never formalized it, the child cannot rely on that parent until the registration happens. The parent must actually be Portuguese, with a birth record in the Portuguese civil register.
Four documents form the core of the application: - The child's full-text birth certificate from the Brazilian registry office, with a Hague apostille - The Portuguese parent's birth record, issued in Portugal - Form Modelo 1C for minors, available at irn.justica.gov.pt - Photo ID of the legal representative who signs
Who signs the declaration
The child signs nothing. The declaration that the child wishes to be Portuguese is made by the legal representatives, usually both parents. The signatures must be notarized at a registry office or made in person at a Portuguese consulate. Form Modelo 1C shows which fields each representative fills in. Children under 14 do not have to present their own ID.
The fee exemption
Minors are exempt from the registration fee the IRN charges for nationality by attribution. Adult children of Portuguese citizens pay it. The current amount is at irn.justica.gov.pt/Custos-dos-servicos, because the Government updates the fee tables. The exemption for minors is set by law and applies wherever the application is filed.
The priority queue
The IRN gives priority to applications for minors. The review time is much shorter than for adults on the same path. Current figures are in the service status table at irn.justica.gov.pt, by type of application and by office. If the child turns 18 before the case is decided, it moves to the adult queue and loses priority. That is why filing while the child is still a minor makes a real difference.
Felipe is 7 and lives in Recife. His mother was born in Lisbon and her Portuguese citizenship is registered. His parents ordered Felipe's full-text birth certificate at the registry office and had it apostilled the same day. His mother ordered her own birth record through the IRN's Civil Online. With both documents in hand, they filled in Form Modelo 1C, had their signatures notarized, and filed the application. Felipe went into the minors' queue.
If the application is not made before 18, the person can still apply as an adult under the same paragraph (c). There is no deadline. But they lose the fee exemption and move to the adult queue, which takes much longer. Waiting has a practical cost.
Linha Reta drafts the declaration of intent and the complete list of documents for your case. You order the records at the Brazilian registry office and in Portugal, get the apostilles, and file the application with the IRN.