Going from Lisbon it is a 40 km drive? Take the A2 South Highway, drive towards Sesimbra, turn right after Fernão Ferro to Algarim. Turn right again to beaches, also known as “Praias” in Portugese.
When you get to the parking lots, then leave your car before the beach. When at the beach turn left and get a nice full body tan anywhere after the first spring.
There is bar and restaurant on the textile area of the beach.