A long thin sandbar of pine forest and white-sand beach stretches south from the mouth of the Sado, reached by a regular car-and-passenger ferry from Setúbal's harbour (about 20 minutes crossing). The Atlantic side has miles of empty surf beach; the estuary side is calmer and warmer, with views back across the water to the Arrábida cliffs.
A cluster of modern resort hotels and a casino occupies the tip of the peninsula, but walk a few kilometres south and you are alone on the sand. The Roman ruins of Cetóbriga, a fish-salting town active from the 1st to 5th centuries AD, can be visited at the northern end.