Tadotsu is a town located in Nakatado District, Kagawa Prefecture, Japan. As of 1 October 2022, the town had an estimated population of 22,124 in 10365 households and a population density of 270 persons per km2. The total area of the town is 24.39 square kilometres (9.42 sq mi).

Setonaikai National Park is a Japanese national park, comprising areas of Japan's Seto Inland Sea, and of ten bordering prefectures. Designated a national park in 1934, it has since been expanded several times. It contains about 3,000 islands, known as the Setouchi Islands, including the well-known Itsukushima. As the park encompasses many non-contiguous areas, and covers a tiny proportion of the Inland Sea's total extent, control and protection is problematic; much of the wider area is heavily industrialized.