At the time of the discovery, the carijos Indians gave the island the name of Babitonga, which when translated means "Earth in the form of a bat". Today, this title identifies the great bay of calm waters that advances towards the West, until Rio Cachoeira, in Joinville.

Babitonga is the largest navigable bay in the state of Santa Catarina. Extending in the East / West direction, it is sheltered from the South wind, making its waters democratic; you can navigate the bay in powerful boats, in silent sailboats and in small canoes. The port and downtown of San Francisco do Sul, with its historic house, are just at the entrance. At the bottom of the bay, after passing through 24 islands, one will arrive to Lagoa de Saguaçu and Rio Cachoeira, a path traveled by the immigrants who founded Joinville.