The Serra da Arrábida runs along the coast between Setúbal and Sesimbra: a low limestone ridge of dense Mediterranean scrub dropping straight into clear turquoise water. The road through the park, the EN379-1, is one of the great drives in southern Portugal — switchbacks, viewpoints, and pull-outs above hidden coves.
The two best beaches inside the park, Portinho da Arrábida and Galápos, are small white-sand bays sheltered by cliffs. Both fill up in July and August (a shuttle bus operates from Setúbal in season) but feel almost abandoned in spring or autumn. The convent of Arrábida, halfway along the ridge, can be visited by guided tour booked through the park office.