Desafio 4 Ilhas — Montão de Trigo

Rising ten kilometres off the coast of São Sebastião, the sheer form of Montão de Trigo juts directly from the open ocean without a single strip of sand. This dramatic offshore sentinel sets the stage for Desafio 4 Ilhas — Montão de Trigo, an open water sea challenge held in the waters of São Sebastião, on the northern coast of São Paulo in Brazil. Conceived as an immersive sports tourism journey, the event lets marathon swimmers tackle distances ranging from 2,000 metres up to 12,000 metres, with intermediate courses of 4,000, 6,000, 8,000, and 10,000 metres available to suit different endurance levels. Out on the open water, navigation stays unusually intuitive because the island itself acts as a massive natural lighthouse.

Its conical silhouette dominates the horizon from miles away, giving you an unmistakable sighting mark with every stroke you take through the ocean swells. Throughout the crossing, held during an open water swim camp in November, safety is closely coordinated by A3 Sports. Escort boats and paddlers in kayaks shadow the swimmers across the course, while dedicated hydration stations are anchored every two kilometres to keep you fueled through the rolling coastal currents.

Underwater caverns and volcanic reefs around Montão de Trigo

The seabed surrounding Montão de Trigo tells the story of ancient volcanic eruptions that shaped the coastline. Exposure to relentless sea spray and wind has carved the cliffs into jagged crests, fissures, and overhangs that plunge straight beneath the waves. Water depths around the perimeter drop quickly from 3 metres near the rocks down to 20 metres. Along the northwestern and southern flanks, this underwater terrain opens into cavernous rock formations that make swimming close to the island feel like exploring a sunken mountain. Although the island has no conventional sandy beaches along its perimeter, it conceals a sheltered natural pool with turquoise water and pale sand beneath the surface. The sea here is remarkably transparent, drawing freedivers and surfers, with clarity and water warmth reaching their peak during the Brazilian summer months.

Centuries of Caiçara fishermen on isolated Montão de Trigo

Today, Ilha Montão de Trigo holds the unique distinction of being the only permanently inhabited offshore island in the entire municipality of São Sebastião. A traditional Caiçara community of around fifty residents makes its home here, living in close harmony with the sea and relying almost entirely on artisanal fishing. Reaching the island's interior is an adventure in itself, as there are no piers or sand flats to welcome visitors. Boat access requires careful timing to step directly onto the sea-washed rocks in the swell. From the landing ledge, a steep and demanding footpath climbs through the forest toward the summit, where communication towers provide surprisingly modern connectivity. Swimmers who take on the hike are rewarded with an extraordinary panoramic sweep of the northern São Paulo shoreline and, on clear afternoons, the distant silhouette of Ilhabela rising across the channel.

The Atlantic Forest shorelines of Juqueí and Boiçucanga

Back on the mainland ten kilometres to the north, the starting beaches nestle against the towering coastal ranges of the Serra do Mar State Park. Here, the lush canopy of the Atlantic Forest tumbles straight down the steep slopes to meet the ocean, feeding clear rivers and hidden freshwater waterfalls just behind the surf. Along the beachfront of Juqueí, strict environmental ordinances ban tall high-rises and limit all residential construction to two stories, preserving an unbroken view of the sea and the offshore silhouettes of Montão de Trigo, Ilha das Couves, and Ilha dos Gatos. Just up the coast lies the sweeping, horseshoe-shaped bay of Boiçucanga, flanked by Maresias and Camburi.

While its exposed outer corners catch the open ocean swell, the sea settles into calm shallows on the left where the Boiçucanga River empties out and local artisanal fishermen dock their wooden boats. The right corner of the bay provides one of the region's most celebrated sunset viewpoints, watching the sun sink into the Atlantic with Montão de Trigo framed against the horizon. From the beach, shaded trails lead directly into the forest canopy toward cascades like the Ribeirão do Itu waterfalls.

From Praia da Baleia to the Alcatrazes marine sanctuary

Next door, the Saí River estuary creates a gentle lagoon that splits the beach at Barra do Saí, offering shallow, tranquil waters on its left bank before giving way to rolling surf along the rocky headland of Canto Bravo. Farther out across the horizon lies the wild Alcatrazes Archipelago, a strictly protected scientific sanctuary enclosed within the Tupinambás Ecological Station. The pristine marine boundary of the Alcatrazes Archipelago underscores the wild, untouched character of the São Sebastião coastline.