This remote and very basic hostel with thatched wooden huts is straight out of Robinson Crusoe. The French owners will collect you from Puerto de Cañas (the pier in Cañas town) and take you to the island. They also provide mangrove tours by kayak, turtle tours and snorkeling, and can provide meals (US$10).
Pachamama has a turtle-protection program in place with a nursery that can accommodate more than a hundred nests. An important warning: mosquitoes can be brutal here. Wear long sleeves and trousers at night and bring lots of bug spray.