The southern shore of Ilha Grande, off the coast of Rio de Janeiro state, is one of the few pieces of Brazil's Atlantic coast that is protected as a strict biological reserve, meaning ordinary visits are not allowed. The Praia do Sul reserve was created to guard a long, curved beach backed by a lagoon, a mangrove and a fringe of forest, and it is one of the places where sea turtles come ashore to lay eggs. The island as a whole has no cars, only footpaths, boats and a tradition of fishing villages, and most of its interior is covered in Atlantic forest, which survived because the island had a prison for much of the twentieth century and was kept off limits.
The wildlife is a draw, with howler monkeys, tamarins, agoutis, toucans and hundreds of bird species, and in the water, turtles, rays and dolphins. The lagoon behind the beach acts as a nursery for fish, and the sand is white and quiet. Because the reserve is strictly controlled, you can see it only with researchers or by special authorisation, and enthusiasts should not try to land without permission. The nearby beaches, such as Lopes Mendes, are open to walkers and make a good alternative.
There is no riding on the island itself, so the motorbike stays on the mainland. The ride along the coast from Rio to Angra dos Reis follows the Rio-Santos highway, BR-101, with a surface that is mostly good, long curves and views of bays full of small islands, and heavy traffic on weekends and holidays. Boats to Ilha Grande leave from Angra dos Reis and from Mangaratiba, with a crossing of an hour or two, depending on the vessel, and you leave the bike in a guarded car park.
Angra dos Reis, a city of over a hundred and fifty thousand people about eighteen kilometres away, has fuel stations, supermarkets and ferry terminals, so take all your supplies there. Vila do Abraão, the main village on the island, has a few small shops, restaurants and inns, but cash can run out, so carry reais. Weather is warm and humid, with heavy rain from December to March, and the best months are April to October. Bring sun protection, insect repellent and a rain jacket for the boat.