G1, the internet portal of the Globo television network, said the accident took place today afternoon, as the bus was traveling between Paraty and Trindade, a beach about 30 kilometers (19 miles) to the south.
The news report included a video showing the bus overturned, on the shoulder of the road. The injured have been taken to area hospitals, the report said.
Calls to area firefighters and police went unanswered. Paraty is roughly halfway between Rio de Janeiro and Sao Paulo and is a popular tourist destination for residents of both cities.