It is separated from the mainland by the estuarine lagoon channel of the Mar Pequeno, the Valo Grande and the mouth of the Ribeira de Iguape River.

[1] The island is part of the Atlantic Forest Biosphere Reserve, and has been recognised by UNESCO as a World Heritage Site.

Since 1970 real estate speculation led to unplanned authorization of hundreds of lots, leading to disorderly occupation of land on the island.

[7] Federal decree 89.336 of 31 January 1984 declared that the Ilha Comprida was an area of relevant ecological interest and recommended that it be made a conservation unit.

[9] Starting in August 2015 the Institute for Ecological Research (Ipê) has partnered with the São Paulo Foundation for Conservation and Forest Production to develop a management plan for the APA.

[10] The management plan, due to be completed in August 2016, would describe fauna, flora, physical environment and socioeconomic aspects.

Preparation of the plan involved consultation with local residents, civil society organizations and government agencies.