The beaches along the northern coast of the state of São Paulo are popular among Paulistanos as weekend destinations and are, in my opinion, underrated by the international tourist industry (and I hope they stay that way!). The closest beaches are in Guarujá and the port city of Santos, but these beaches are overcrowded, overdeveloped and somewhat polluted. Keep heading northeast along the coast (the trip, by car, takes between two and four hours without traffic). The first of the nicer beach areas that you will reach is Riviera de São Lourenço, which offers the amenities of a small town in addition to their decent beaches. Personally, I prefer the beaches that lie beyond, starting after Boracéia. The scenic coastline, covering the municipal regions of São Sebastião, Caraguatatuba and Ubatuba, offers sandy beaches framed by mountains and tropical rainforest. Some have comfortable hotels, although at many of the beaches in this area, rustic "pousadas" are the norm. Some beaches even have campsites (but be aware that camping on the beach itself is usually prohibited). Beaches are most crowded between Christmas and New Year’s and during Carnaval; this is also when the nightlife is liveliest.
If you are near the beach of Maresias and enjoy dancing, the nightclub Sirena is worth checking out. Some of São Paulo’s best DJs spin there during the high season, and its open-air, rainforest setting is uniquely fantastic.
Spring and fall, or even weekdays during the summer, allow for a more relaxed experience, and some beaches remain virtually deserted even at the peak of summer. One of the greatest attractions of the northern Paulista coastline is its preserved stretch of Atlantic Rainforest. This forest used to extend up the entire coastline of Brazil, but has been decimated by the expansion of development and agriculture. Much of the remaining forest lies in the state of São Paulo. It is possible to hire a guide who will take you into the jungle on an "eco-tour," where you will learn more about the fauna and flora of this wild and dense rainforest. Also, ask around for trails that lead to mountain waterfalls—the trek through the jungle (ranging in length from five minutes to many hours) will be hot and humid, but the breathtaking beauty and the chance to swim in natural, clear pools in the middle of the rainforest are worth the sweat.
For another paradisiacal experience, hire a boat on a sunny day and go out to a nearby island, where you can snorkel or swim in the emerald-green waters.
Depending on when you go and on the beach you choose, nighttime activities vary in selection and crowdedness. Some beaches are downright deserted, although even these are located near beaches that will have at least a few bars and restaurants. The streets, bars and restaurants of the most popular of the beaches will be thronging with people from the city. Friday night traffic to the coast is often intolerable, as is the Sunday-night return. If you can, avoid these peak hours. The coast can be reached via inter-city buses run by private companies, and these are usually safe and reliable. You’ll want a bus that takes the Rio-Santos highway. When you board, tell the driver what your destination is, and he can let you know when you’ve arrived.