Sao Sebastiao is a Brazilian municipality, placed at the southeast coast of Brazil, inside the kingdom of Sao Paulo. The population in 2009 become 76,344, its density turned into 182.5/km² and the region is 403 km². The Tropic of Capricorn lies 25 km north. The municipality existed considering that 1636 and formed part of the vintage hereditary captaincy of Santo Amaro.
The archipelago municipality of Ilhabela is placed on the east coast of the city; the most important island of the archipelago is likewise referred to as Sao Sebastiao. Between the town and the island, there may be the Sao Sebastiao channel with 30 kilometres in period, and width 2 km being the shortest crossing. There is an oil terminal at the channel, owned through Transpetro, a subsidiary of Petrobras. The city is famous for its beaches, which makes it a popular tourism destination, in particular for human beings from the state of Sao Paulo. Near the boundary with Bertioga, there may be a small Guarani village managed with the aid of FUNAI.