Green island is a small volcanic island in the pacific ocean about 33 km 21 mi off the eastern coast of taiwan it takes about 50 to 60 minutes from taitung city by ferry the island is primarily noted for its prisons and penal colonies green island first served as an isolated spot and place of exile for political prisoners during the martial law period of taiwanese history from late 1940s to 1980s you will find many interesting stories and very beautiful scenery here if you are looking t