While acquired Portuguese citizenship (nacionalidade por naturalização), as a rule, can only be transferred to minor children (Art. 2.º, n.º 1, al. d) and Art. 14.º, Lei da Nacionalidade – Lei n.º 37/81), your 30-year-old son would not automatically become Portuguese when you naturalize. However, he can still obtain Portuguese nationality if he qualifies independently under the law. The most common pathways are: Residency route – If he relocates to Portugal and becomes a legal resident for the minimum period (currently 5 years, counted under Art. 6.º, n.º 1, Lei da Nacionalidade, as amended by Lei Orgânica n.º 2/2020), he may then apply for naturalization. Family reunification + residency – As the adult child of a Portuguese citizen, he may apply for a residence permit via family reunification (Art. 98.º and Art. 99.º, Lei de Estrangeiros – Lei n.º 23/2007, as amended). After 5 years of legal residence, he can request nationality under Art. 6.º, n.º 1, Lei da Nacionalidade. Dependency exception – If he is financially dependent on you or has a disability that makes him dependent, the authorities may accept family reunification even as an adult (Art. 99.º, n.º 2, Lei de Estrangeiros), which then leads to the same 5-year residence track. Marriage or de facto union – If he marries or enters into a legally recognized de facto union with a Portuguese citizen, he can apply for nationality after 3 years of marriage/union (Art. 3.º, n.º 1, Lei da Nacionalidade).
