Built in 1676, after the end of the Restoration War, its mission was to reinforce the defense of the coast between the Santiago de Sesimbra Fort and the Santiago do Outão Fort.
It is in this building that the Luís Saldanha Oceanographic Museum is housed.
The Santa Maria Fort is also sometimes referred to as “Forte de Nossa Senhora da Arrábida”, “Forte da Arrábida” or “Forte do Portinho da Arrábida”.