Praia do Sul Biological Reserve, Biological reserve in Ilha Grande, Brazil

Praia do Sul Biological Reserve is a protected area on Ilha Grande island comprising Atlantic Forest sections alongside coastal wetlands, rocky shores, and shallow lagoons. The reserve combines terrestrial and marine protection zones that support distinct ecological communities across several thousand hectares.

The reserve was created by decree 4,972 of 2 December 1981 on Praia do Sul, in the municipality of Angra dos Reis, to preserve the natural ecosystems and their native flora and fauna. It lies within the Tamoios Environmental Protection Area (1982) and the Bocaina Mosaic (2006), and in 1990 was joined to the 1,312-hectare Aventureiro Marine State Park. On 28 May 2014 its area was cut by 2.7% to accommodate the Vila do Aventureiro, leaving about 3,502 hectares.

The reserve protects sambaquis and archaeological sites of the region's early inhabitants, called the "axe makers of Ilha Grande". Inside its limits lies Vila do Aventureiro, a traditional caiçara community of about 100 people who lived there before the reserve was created and whose livelihood rests on fishing and tourism. Visitors sign a Termo de Compromisso at TurisAngra in Angra dos Reis and receive an identification wristband.

Entry to the reserve requires advance permission, as it primarily serves research and conservation purposes rather than casual tourism. Visitors should inquire locally about current access conditions and necessary procedures before planning a visit.

Archaeological evidence shows that people inhabited this island thousands of years ago and possessed specialized skills such as seafaring and diving abilities. These findings reveal that the area holds deep human history alongside its contemporary role as a nature reserve.