A good and cheap option in case you don’t have a boat is to rent one at the Santa Luzia Dock. There are price charts to several points at the Long Island. Depending on how many people you have on your party it can be very cheap. You can rent a boat to take you to the islands and come back at the end of the day to pick you up or it can stay with you the entire day.

Another option is the BARCAS S/A (EX - CONERJ) ferry (see at Ilha Grande). It makes the journey Angra-Abraão (Ilha Grande)- Angra everyday).

See below some pictures and pricing.