Fuga das Ilhas — Barra do Sahy

Boats ferry thousands of swimmers offshore to an isolated rocky outpost, where the only way back to Barra do Sahy is a direct stroke across open Atlantic water. Known as Fuga das Ilhas, this open water swimming race takes place in the sea off Barra do Sahy, in the municipality of São Sebastião along the northern coastline of São Paulo state in Brazil. Organized by Norte Marketing Esportivo, the event is held in late November, serving as a signature crossing within the Circuito Aqua, widely recognized as the largest open water swimming circuit in Brazil. The core challenge spans a direct 1,500-meter crossing from the rocky islet back to the mainland shore, while past editions have gathered as many as 3,000 swimmers covering a 2,000-meter course through clear sea.

Competitors board shuttle boats for the trip out to the island, diving into the waters. Out in the open passage between the rock and the mainland bay, swimmers regularly encounter rolling ocean swells, long wavelength surface waves that can lift the field and challenge rhythmic breathing. Under these open water conditions, sighting and navigation emerge as the primary hurdles for swimmers learning to hold an efficient line toward the mainland.

The volcanic archipelago and waters of São Sebastião

The scattered islands and dramatic rock formations rising along this coastline were sculpted by ancient volcanic activity. Just off Praia da Baleia, about two and a half kilometers long and endowed with one of the most extensive stretches of Atlantic Forest on the São Paulo coast, sits a small island shaped like a whale that gives that stretch of shore its name. Further offshore, Ilha Montão de Trigo stands out as the only permanently inhabited island in the municipality, home to an isolated community of 52 caiçara residents. These waters host other open water traditions as well, including the Volta do Parcel, a competition starting and finishing at nearby Juqueí beach that loops swimmers around an unnamed skerry.

Along neighboring headlands, coastal topography varies markedly: Praia Preta, nestled between Juqueí and Barra do Saí, offers dark, firm sand alongside transparent, sheltered waters favored by small boats, with the lookout of Morro da Prainha rising just meters away to reveal views across the entire coastal region. Beyond the sheltered pockets, the open coast reveals the raw power of the Atlantic. At beaches like Boiçucanga, the sea is often calm along thick, yellowish sand and crystal turquoise water. At Maresias, a five-kilometer expanse of soft, yellowish sand discovered by surfers in 1974, the ocean regularly generates massive waves and strong currents. Breaking waves can surge across the open ocean whenever wave amplitude grows steep enough, and plunging waves crash over reefs or sudden shallow banks.

Where rip currents develop, narrow and powerful channels of water flow straight back out from the breaking surf. Swimmers who encounter such currents avoid fighting the seaward pull directly, staying calm and swimming parallel to the shoreline until they escape the grip of the flow. At Guaecá beach, conditions continually alternate between placid flat water and heavy currents, with trails at its southern point leading to secluded coves where swimming back out through the sea is sometimes the only way home after heavy rainfall.

As Ilhas, the island facing Barra do Sahy

The island called As Ilhas is a single place, despite the plural name, and it faces the beach of Barra do Sahy in São Sebastião. As Ilhas lies about 1.5 km from Barra do Sahy and can be reached only by boat, although some people paddle there by kayak or stand-up paddleboard. The nearest beaches to As Ilhas are Barra do Sahy and Juquehy, and boats that take visitors across to the island leave from both. On As Ilhas the white sand reaches two further beaches of calm, clear water and a natural pool, and the Ilha dos Gatos can be seen right next to it. At Praia de Fora on As Ilhas, near a rock wall, underwater visibility reaches down to 10 metres, with octopuses and corals, and stingrays and turtles along the sides. The Fuga das Ilhas is one of the three stages of the Circuito Aqua, together with the Volta do Parcel in Juquehy and the Travessia Maravilhosa in Rio de Janeiro.

Serra do Mar and the Alcatrazes sanctuary

The Serra do Mar mountain range features dense Atlantic Forest that rolls down steep slopes to meet the ocean with coastal rivers and cascading waterfalls. The sheer volume of water cascading from these mountains can be staggering, exemplified on February 18, 2023, when the South Coast of São Sebastião recorded a historic rainfall of 682 millimeters. Yet despite these mountain torrents, coastal waters at spots like Praia da Baleia maintain excellent sanitary quality for open water swimming. Farther out in open water lies the Alcatrazes Archipelago, fully protected within the Tupinambás Ecological Station, where all fishing and diving are strictly prohibited to preserve marine biodiversity.

The island of Alcatrazes provides a sanctuary for endemic wildlife that evolved in complete isolation, including two frog species, Cycloramphus faustoi and Ololygon alcatraz. The island is also the only home of the Alcatrazes lancehead, a small pit viper that grows to about 50 centimeters and lives exclusively within the low Atlantic Forest vegetation of the distant island. Care for the coastline extends directly to the mainland shores that frame the race course. In 2016, a proposal was advanced to expand a one-square-kilometer protected area near Barra do Saí to over three square kilometers to halt real estate development and preserve native coastal vegetation. Similar lush greenery crowns the hills rising behind the homes at Guaecá, and organized walking trails wind through the Atlantic Forest canopy above Maresias, keeping the coastal ecosystem vibrant and protected.

Barra do Sahy: the estuary, suspension bridge, and sand-floor life

The crossing concludes upon the sands of Barra do Sahy, where the Saí River empties directly into the sea. The river mouth forms a calm, shallow lagoon that splits the beach in two, creating a tranquil left bank where the freshwater joins the ocean over gentle shallows. In sharp contrast, the right side of the beach, known locally as Canto Bravo, features stronger waves and opens the way to a small bay framed by rocks. At the left corner where the river reaches the sea, a wooden suspension bridge spans the water, connecting the shore to a small chapel. The Vielinha do Sahy is a charming alleyway celebrated for its walls adorned with artistic expressions and philosophical phrases.

After exiting the surf, swimmers unwind in casual seaside restaurants, some featuring traditional sand floors, serving chilled refreshments alongside plates of fried fish and fresh seafood. Sitting barefoot by the mouth of the Saí lagoon provides the perfect finish to a swim across the waters of São Sebastião.