The Seto Inland Sea is the body of water between the Japanese main islands of Honshu, Shikoku, and Kyushu. Often referred to simply as the Inland Sea, it has been a crucial waterway for trade, travel, and warfare since ancient times, and is dotted with some 3,000 islands. Some of the islands are inhabited and many more are uninhabited. Shodoshima, the second-largest island in the Seto Inland Sea and famed for its olive plantations, and Naoshima, the “art island” that is one of the main venues of the Setouchi Triennale art festival, are popular tourist destinations. Ferries offer regular service from Takamatsu to both Shodoshima and Naoshima as well as to several smaller islands.
The beauty of the Seto Inland Sea archipelago, with its lush forests, sandy beaches, and mostly calm waters, can be admired from observation points along the coast of Kagawa. These include Mt. Yashima, a volcanic plateau that towers over the city of Takamatsu, the Goshikidai Highland between Takamatsu and Sakaide City, and the Shonai Peninsula in the western city of Mitoyo. Visitors traveling by car or train can also enjoy views of the islands when crossing the 13-kilometer Seto Ohashi Bridge, which connects Shikoku and Honshu.