THE sun was blazing at the Tostex beach club in Bahia, Brazil, and the tanned and toned partygoers were lounging on rustic queen-size beds, fighting off the unrelenting mosquitoes on an otherwise lazy day. A scruffy D.J. from S?o Paulo who went by the name Juli?o swayed in his thatch-roofed booth and cranked up a funky remix of Laurent Garnier's saxophone-infused song “The Man With the Red Face.” The sculptured 20 and 30 somethings — models and actors sprinkled in with S?o Paulo's elite professionals — sipped colored martinis and bronzed on leopard-print pillows, as gentle Bahian breezes tickled their skin. Few flinched as a steady stream of private planes and helicopters zipped above the water. It was another picture-perfect day in Trancoso, a former fishing village that has turned into a super-trendy getaway for Brazilians and fashionable jet-setters willing to pay St. Tropez prices for rustic accommodations on an unspoiled beach. Situated on the palm-fringed coast of Brazil's Bahia state, Trancoso still looks like the hippie getaway that first made the town popular 20 years ago, with its uneven cobblestone streets and dirt roads. “Trancoso has an energy all its own,” said Paula Vigorito, 40, the owner of Tostex, as she ushered people into her house, which doubles as a store for chic jewelry and sculptured art, for a warm-up party one evening in early January. Inside, guests drank cocktails from plastic cups and grooved to a D.J. In January, Rodrigo Hilbert and his wife, Fernanda Lima, both Brazilian television actors, were spotted dancing at the Pink Elephant beach club. Francesca Versace and Dimitri Mussard, an heir to the Hermès fortune, party-hopped in Trancoso over the New Year's holidays. And the Brazilian singer Bebel Gilberto tied the knot here in February in an informal wedding with 50 guests, which was fawningly documented by the Brazilian gossip site Glamurama. And then there are the regulars, bold-faced names like Naomi Campbell, Gisele Bündchen and Diane von Furstenberg, who rent or own more secluded summer houses up the beach. The heart of Trancoso's party scene is the Quadrado, a grassy, open field near a cliff overlooking the beach flanked by the town's nicest restaurants and boutiques, in simple one-story houses. During the peak season, which goes from about December through February, Trancoso feels like a vampire town. During the day, the Quadrado is eerily quiet, with most stores and restaurants shuttered until about 3 P.M. But at night, it springs to life: multicolored lights sparkle from low-hanging trees, friends sit at outdoor tables on the dusty edge of the grass, and art galleries stay open well past midnight. Open later are the beach bars and clubs. While a few places feature forr?, traditional Brazilian dance music, Trancoso's night life feels more like an expensive S?o Paulo nightclub — beach style. Paulistanos, as S?o Paulo residents are called, started trickling in during the mid-1970s, mostly college-educated hippies and artists, who created a kind of bohemian village in Bahia. By the 1980s, businessmen arrived and built shiny vacation homes. But it wasn't until 1999, with the building of a new highway linking the region to the commercial airport in Porto Seguro, that Trancoso really took off. Then in 2003, a Club Med opened 10 minutes from the center of town. The last decade has added Terravista, a gated golf course resort, where mansions designed by big-name Brazilian architects like Fabrizio Ceccarelli sell for up to 5 million reals (about $2.8 million). The opening of the private Terravista Airport and helipad between Trancoso and Arraial D'Ajuda allows Gulfstream planes and private helicopters to whisk billionaires to S?o Paulo in around two hours. “Everybody here seems to have a helicopter,” Ms. Vigorito said. For those without beachfront homes, swanky hotels have arrived, catering to well-heeled vacationers. In early 2009, Wilbert Das, the former creative director at Diesel, opened Uxua Casa Hotel, a complex of eight bungalows and a treehouse set amid tropical gardens that features a pool lined with 40,000 pieces of green aventurine quartz. The next hot spot, however, will likely be the Hotel Fasano, the luxe resort that is planning to build 40 bungalows and 25 villas along a private beach, about a mile south of the Quadrado. It is set to open in 2012, said Paula Bezerra de Mello, a spokeswoman for the Hotel Fasano in Rio de Janeiro. Despite star power and wealth, however, Trancoso remains surprisingly mellow. The slow service can even be maddening at times. A grilled cheese sandwich at Tostex can take an hour and 15 minutes on a busy afternoon. A shrimp and pasta dish might be misplaced at the Paradise beach club. The beaches remain pristine. Trancoso rests on a single long beach that fans out to the left and right of the Quadrado. Aside from a few inns and beach clubs like Tostex, there is only a smattering of homes, with most set back from the water. Building restrictions have prevented taller condos and hotels, preserving, for now, the eco-friendly feel. One of the mellowest spots is Espelho Beach, about a half-hour car ride from town, over a winding dirt road, past grazing cows. On a sunny Monday afternoon, a small cluster of beachgoers were lounging on brightly colored pillows at the Pousada e Restaurante do Baiano, a colonial-style inn where the D.J. was playing a down-tempo mix. At the other end of the empty beach, where the water was lukewarm and crystal clear, the rhythms from the inn were drowned out by soft, lapping waves.