Turtle Island, also known as Marathonisi, is a small uninhabited island located off the coast of Zakynthos (Zante), a Greek island in the lonian Sea. It is named after its turtle-like shape and is famous for being a nesting site for loggerhead sea turtles, also known as Caretta caretta. The island is protected as part of the National Marine Park of Zakynthos, and visitors can explore its beautiful beaches, crystal-clear waters, and rich marine life.