Boipeba is less a single beach than a series of ecosystems stitched together by tide. Long reefs run parallel to the shore, breaking the Atlantic swell before it reaches the coconut palms and filling the shallows with warm, clear pools shot through with coral, algae, sea urchins, and starfish. Behind the beach the land changes quickly: dense patches of Atlantic rainforest, then saltmarsh, then mangrove channels reaching inland toward the Inferno River estuary. Sea turtles nest on the quieter stretches, and birders who walk the forest trails pick up armadillo tracks in the sand and the rustle of small reptiles in the leaf litter. The whole island was declared an Area of Environmental Protection by the state of Bahia in June 1992, a designation that the residents themselves helped shape through Amabo, the local Association of Residents and Friends of Boipeba, to keep tourism from doing to their reefs what it has done elsewhere.

There is no ferry straight from Salvador. You catch the ferry across the Baía de Todos-os-Santos to Bom Despacho (about 45 minutes), a bus down the coast to Valença (about two hours), and then a boat for the last leg. The slow boat is the village ferry in all but name - four hours of Brazilian coastline and cargo and conversation. The speedboat does the same run in about 90 minutes. The other way in is more picturesque: from Morro de São Paulo, a 4x4 jeep rattles down the spine of Tinharé before handing you off to a short river crossing by launch. Either way the island meets you the same: a wooden pier, the slap of water, and a welcome committee of guesthouse owners with hand-drawn signs. The village's internal roads are soft sand - cyclists curse them, walkers learn to stick to the harder edges - and the police bike outnumbers the patrol car by one to zero.

The village clusters around the port at Velha Boipeba, and everything gets quieter as you walk south. By the time you reach Moreré the crowds thin to a handful of pousadas; continue past the tide pools, where horse riders lead you across shallow channels at low tide, and you arrive eventually at the beach of Cueira and then Ponta dos Castelhanos at the island's southern tip. Snorkeling is how most visitors meet the reef - there is no scuba operation on the island, so this is a mask-and-fins kind of place. The best mornings start early, when the rising tide still leaves the pools accessible and the sun has not yet turned the sand into a griddle. Watch for bicho-de-pé, the tiny burrowing parasite that prefers bare feet to shoes; a little caution is all the island asks in return for giving you the reef.

Because there are no cars, food on Boipeba arrives by boat and by memory. Restaurants serve family-size portions meant to share - the high tag on a moqueca makes sense once you see the clay pot come out bubbling for three. A beach shack near the main port sells sandwiches for walkers; the Family Guest House delivers wood-oven pizza on weekends, summoned by WhatsApp and carried across the sand on foot. Lodging clusters in two zones: near the port for convenience, near Miereles for quiet. The Abaquar Hostel, run by a Belgian-Portuguese couple named Peter and Fernanda, serves the kind of breakfast - garden eggs, tropical fruit, strong coffee - that is meant to carry you through to sunset. Generators hum in the evenings because the island has no fixed grid. When they switch off, the Milky Way leans down over the reef, and you remember why you came.