Ilhabela is an archipelago and city situated in the Atlantic Ocean six kilometres off the coast of São Paulo state in Brazil. The city is 205 km (127 mi) from the city of São Paulo and 340 km (210 mi) from the city of Rio de Janeiro. The largest island, although commonly called Ilhabela, is officially named Ilha de São Sebastião. It, the other islands and the islets make up the municipality of Ilhabela.

São Sebastião is a Brazilian municipality, located on the southeast coast of Brazil, in the state of São Paulo. The population in 2020 was 90,328, its density was 185/km2 and the area is 403 km2. The Tropic of Capricorn lies 25 km north. The municipality existed since 1636 and formed a part of the old hereditary captaincy of Santo Amaro.