Ilhabela is part of the Metropolitan Region of Vale do Paraíba e Litoral Norte. The population is 32,197. The islands in total cover 347.52 km2. During the holiday months, up to one hundred thousand people may be on the island, since it is a popular destination for tourists. To access the city, one must take a boat or ferry in São Sebastião, as there are no roads which reach it. During the summer, one may wait several hours to take the ferry boat. The ferry takes 15 minutes to cross the channel between the two cities.
Before Portugal colonized Brazil in 1500, an indigenous tribe called the Tupinambas, inhabited the island. They called the island 'Ciribai', which means tranquil place.
The island was named São Sebastião Island by Amerigo Vespucci, on January 20, 1502. During the 16th century, the Portuguese set up military points on the shore of São Sebastião Island.
In August 1591, notorious British explorer Thomas Cavendish spent some time in the island. He was on an expedition to the south of the Strait of Magellan accompanied by navigator John Davis and then returned to Brazil, where they hid and refueled in Ilhabela and looted Santos and São Vicente.
On September 3, 1805, the Governor of the Province of São Paulo, Antônio José da França e Horta, decreted the political-administrative independence of the county. The Island had already 3.000 inhabitants at that time. The new county was named Villa Bella da Princeza, paying homage to the princess of Beira.
On November 30, 1938, during the Getúlio Vargas' Estado Novo, an act altered the name of the county to Formosa. Six years later, on November 30, 1944, another act ultimately changed the name to Ilhabela.
Since the second half of the 20th century, the city is a popular touristic destination. Among the current critical issues of the island, is the lack of proper sewage pipes to collect all houses' wastewater. As of January 2012, 46,6% of the buildings in the island lacked such infrastructure. In February 2016, the city hall announced R$12 million to be invested in sewer systems for the southern part of the city. By the time it was announced, Ilhabela was the worst coastal municipality in the state of São Paulo in terms of sanitary treatment, according to a research by the State Secretary of the Environment - 35% of the city's sewer is collected, pre-conditioned and released on the sea, according to the secretary, while the city hall claims 61% of the city is covered by sewer systems.
The municipality comprises the main island, Ilha de São Sebastião, and three smaller inhabited islands: Buzios and Vitória islands, 7½ and 2½ km away from the northeastern tip of the main island, respectively, and Pescadores Island, near Vitória Island. Buzios and Vitória are home to 142 and 50 caiçaras, respectively. There are also the very small islets (das Cabras, da Sumítica, da Serraria, dos Castelhanos, da Lagoa, da Figueira e das Enchovas islands). Almost all the urbanized areas are in the very narrow plains between the sea and the mountains of the main island, preferably at the west part of the island, facing the continent.
A short (30 km) but high mountain range forms this main island, reaching above 1,000 meters in seven different points - Pico de São Sebastião (1,378 m), Morro do Papagaio (1,307 m), Pico da Serraria (1,285 m), Morro do Ramalho (1,205 m), Morro do Simão (1,102 m), Morro das Tocas 1,079 m) and Pico do Baepi (1,048 m). Running approximately 8 km into the Atlantic Ocean off the southeast corner of the island, there is the Península do Boi (Ox Peninsula). The east side of the island is inhabited by very few people, who concentrates mainly on the Castelhanos beach, the only on this side accessible by road. Only 4x4 jeeps are able to cross this particular road, though.)
Most of the city has a humid subtropical climate, but the mountains have an oceanic climate, because of the high altitude. The Atlantic Forest covers the entire city.
Ilhabela is a popular sailing point. Several regattas take place at the city's coast. Also, it is popular for many other watersports, including scuba and free diving. The waters around the archipelago are filled with more than 50 shipwrecks, six of them being opened for visiting via diving. Cetacean diversity is rich in the areas, and whale watchings targeting such as humpback whales, bryde's whales, minke whales, southern right whales, orcas, and dolphins are also available.
There are many hiking trails with varying degrees of difficulty and 360 waterfalls in the Atlantic jungle.
There are 41 beaches on the main island. The ones located along the channel are in general urbanized and feature calm to moderate waves. The ones facing the ocean are clean and less affected by humans, besides featuring stronger waves, which attracts surfers. These can only be reached by foot and/or by boat, the exception being Castelhanos, as explained above. Bonete was considered the ninth best beach of Brazil by The Guardian
The only way to access the island by car is via the ferry boats that cross the channel. Each boat carries up to 70 vehicles and takes 15 minutes to sail through the 2.4 kilometers that separate the two stations.
The SP-131 is the main road on the main island, running from the southwestern coast of the island to its northern coast (both these edges are paved since 2008). The road has three different names throughout its path.