Historically cut off from Lisbon, this narrow isthmus south of the Tagus is wild and rugged as well as lush. In different places, the strip of land plummets toward the sea, stretches along miles of sandy beaches, and rolls through groves heavy with the odors of ripening oranges. With craggy cliffs and coves in the background, the crystalline Atlantic is ideal for swimming, skin-diving, or fishing for tuna, swordfish, and bass.
The area has enjoyed an upsurge of interest since the construction of the Ponte do 25 de Abril, a long suspension bridge that makes it possible to cross the Tagus in minutes -- though traditionalists prefer taking the ferry from Praça do Comércio in Lisbon and docking in Cacilhas. Whichever way of crossing you prefer, once you get to Lisbon's left bank, good roads will help you head rapidly through pine groves to the apex of the triangle known as The Land of the Three Castles: Sesimbra, Setúbal, and Palmela.
The land south of the Tagus River retains vivid reminders of its past, reflected in its Moorish architecture, Roman ruins and roads, Phoenician imprints, and Spanish fortresses. The region's proximity to Lisbon (Setúbal is only 40km/25 miles southeast of the capital) makes it perfect for a 1-day excursion. Though train travel is very limited, the area has an extensive network of ferry connections as well as bus services from Lisbon. You'll find driving to be the ideal way to explore the district at your leisure. Otherwise, you can take a bus from Lisbon to the beaches at Caparica in about 45 minutes.
If you take a ferry from Lisbon's Praça do Comércio to Cacilhas, you can catch a bus there for the beaches of Caparica. If you're visiting the peninsula by bus, use Setúbal as your hub; from there you can take local buses to Palmela and Sesimbra.
In summer, a narrow-gauge railway runs for 8km (5 miles) along the Costa da Caparica, making 20 stops at beaches along the way. If you go by rail to the peninsula, service is from Lisbon to Setúbal. From there, you must rely on buses to visit the fishing villages along the southern coast.