Aka island is located 3km south east of Zamami Port. It is the second largest inhabited island in the Keramas archipelago. Because shell mounds have been found in the western part of the island, it is thought that people lived on the island since a long time ago. There is also the site of Sakuma Castle of the Ryukyu kingdom era. Houses on the island are concentrated on the southern part, and a beautiful beach is located in the north, which is a famous diving point. More and more people are moving to the island for diving these days. In 1998, Aka was connected with a bridge to Geruma Island, which connected it to the air port on Fukaji Island.