There are many beaches in the vicinity of Lisbon. My favourite is the Costa Caparica on the south bank of the Tejo. This section of beach is 10 kilometres long and has wonderful spots for surfing, and is also quieter and more idyllic than the busy Carcavelos. It is popular with the locals, and there are nice restaurants on each section of beach serving fresh fish at fair prices. Those without a car can take a bus from the Praca de Espanha. Once in Caparica, there is a small train that travels along the coast in summer. You simply hop out when you get to the right spot. It's the perfect day trip for sun worshippers and surfers.