Pini Island is one of the Batu Islands (or the Telo Islands, an archipelago of Indonesia located in the Indian Ocean off the west coast of Sumatra, between Nias and Siberut. The three primary islands, of approximately equal size, are Pini, Tanahmasa, and Tanahbala. There are forty-eight smaller islands, of which less than half are inhabited. The islands are governed as a part of North Sumatra province. In Indonesian and Malay, batu means rock or stone. The equator passes through the archipelago, north of Tanahmasa and south of Pini.