Águas Abertas - etapa Búzios

Águas Abertas - etapa Búzios is an open water sea swimming race held at Praia de Manguinhos, in the coastal resort town of Armação dos Búzios in Rio de Janeiro state, Brazil. Organized by Mksesportes, the race sets up its starting base right where the sand links Manguinhos and Rasa beaches, hosted at Clube Aretê Búzios and Belli Belli Praia. This stretch of coast is an ideal arena for open water navigation. Swimmers can choose between two main distances, with courses laid out over 1,000 meters and 3,000 meters marked by turn buoys in the bay. All finishers earn a commemorative participation medal as they step across the timing line. Previous coastal swims connecting João Fernandes to Praia de Manguinhos have showcased the crystal-clear clarity that characterizes this side of the peninsula.

Third edition, April sea and the Búzios peninsula

The second edition of the Águas Abertas stage in Búzios was held on 24 May 2026, according to the results archive of Mksesportes. The third edition of Águas Abertas, Búzios stage, takes place on 18 April 2027 at Clube Aretê Búzios and Belli Belli Praia, on the Manguinhos-Rasa beach. Sea temperature at Armação de Búzios in April averages 25.3°C (77.5°F), with a range from 24°C (75 °F) to 26.7°C (80 °F), according to seatemperature.org. The Búzios peninsula, where the race is held, is 8 kilometers long and has 23 beaches. Armação dos Búzios lies 173 km east of the city of Rio de Janeiro and 24 km southwest of Cabo Frio. On the peninsula, the west coast beaches offer calm, clear waters, while the east coast beaches face the open sea and draw surfers and water sports enthusiasts.

Praia Azeda and Azedinha in the environmental reserve

Praia Azeda sits safely enclosed within an official Environmental Protection Area. Tucked inside this natural sanctuary, the beach is renowned for its calm and crystalline waters, forming an emerald cove where waves rarely break. The transparent water offers swimmers and snorkelers exceptional visibility right from the shoreline. A narrow strip of dark rocks is all that separates Azeda from its smaller companion, Praia da Azedinha. Because the environmental reserve prohibits any modern construction on Azedinha, there are no kiosks or buildings to interrupt the scenery, leaving an unobstructed panoramic view of lush native forest sloping straight into the water.

Praia dos Ossos: eighteenth-century whalers and fishermen

In 1730, shore-based whaling operations were established here, leaving the sand littered with whale bones that gave the beach its enduring name. Along the shoreline, the original fishermen's houses have been carefully restored, creating a picturesque waterfront where historic cottages stand alongside the Armação de Búzios Yacht Club.

The Una River estuary: hypersalinity and mangrove wetlands

The Una River originates at an elevation of 130 meters on the Igarapiapunha hill in Araruama and draws water from the Araruama lagoon system. From there, it winds across the low plains of the Baixadas mesoregion before discharging into the Atlantic Ocean. During the colonial period, the river served as a vital freight highway, transporting agricultural produce from the historic Fazenda Campos Novos down toward Rio de Janeiro. Navigating its channel was never straightforward; an official report from 1934 documented that its shallow depth allowed boats to pass only during high spring tides. In the 1940s, government engineering works drained vast marshes and swamps in the lowland basin to combat malaria and establish rice fields.

Despite these alterations, the Una estuary remains a crucial wildlife nursery supporting 48 distinct fish species. The surrounding wetlands shelter varied crustacean populations, including native uçá, guaiamum, and aratu crabs. During prolonged dry seasons, strong evaporation in the river reaches extremes, pushing water salinity up to 48 grams per kilogram, which substantially exceeds the Atlantic Ocean's typical 35 grams per kilogram. Mangrove wetlands flourish along the shoreline.

Praia de Manguinhos: fishing colonies, mangroves and Porto da Barra

Praia de Manguinhos is defined by a narrow strip of firm, brownish sand bordered by fringing mangrove vegetation. It remains home to an active traditional fishing colony alongside local nautical clubs, filling the shallow anchorage with wooden skiffs and leisure boats. Walking along the shore reveals historical details rooted in the coastal landscape, including a stone pier constructed in bygone centuries by enslaved workers. A secluded foot trail leads to Praia da Tartaruga. Swimmers looking to explore this walking path must time their journey carefully, as the trail is accessible only at low tide when the sea pulls back from the rocks. Unlike many urban beaches in the state of Rio, Manguinhos has deliberately avoided the clutter of temporary kiosks, rented plastic loungers, and roaming hawkers, so visiting athletes should pack their own ground mats, towels, and water.

Instead, the social life of the beach centers on Porto da Barra, an elegant waterfront dining complex located directly along the sand. After crossing the finish line and packing away goggles and caps, swimmers linger at Porto da Barra's seaside tables to enjoy local dishes while watching what is celebrated as the finest sunset in Búzios, glowing across the water on the left side of the bay.