The Serra da Arrábida is about the coast. Praia do Portinho, Galápos and Figueirinha sit right under the mountain, the water shifts from green to deep blue, and the light on the N379 ridge road is best in the late afternoon.
Part of the coastal road is closed to cars, so the easiest way to reach the hidden coves and sea caves is by boat, and the viewpoints buses can't reach are covered by off-road jeep tours. In summer the beaches fill up early — come before midday or arrive from the water.
Before leaving Lisbon or Setúbal, check
which bus reaches each Arrábida beach and where the free 4477 shuttle begins.