Setonaikai (瀬戸内海): Sunset Points

One of the best nature experiences is to watch the sunset. It is worth the effort to visit the Setonaikai (Inland Sea) for this. Planet Ware notes that "The Setonaikai is a wide arm of the sea extending between the islands of Honshu, Shikoku and Kyushu, with about a thousand small islands and islets, magnificent beaches and quiet little coves containing small fishing villages. The exceptionally mild climate ensures a rich and varied pattern of vegetation." Further, "Much of the area was declared a National Park in 1934, including part of the island of Shodojima, the Yashima Peninsula, the island of Sensui, Cape Abuto and Mount Washuzan. The Inland Sea National Park (land are 254sq.mi/ 659sq.km) now extends much farther southwest reaching as far as the coasts of northeastern Kyushu. In the east it extends to the island of Awaji."

Welcome to JP tells us that "The Setonaikai National Park covers the entire expanse of the Inland Sea, measuring about 250 miles/400km and surrounded by the main islands, Shikoku and Kyusyu. The park is home to a thousand small islands, islets and rocks and to the Naruto Strait known for its large whirlpools, called "Uzushio". The Naruto Strait is a narrow channel located between the islands of Shikoku and Awaji, the biggest island in the park. Beautiful beaches, caves, terraced fields and inland sea make this park a popular tourist attraction."

If you want to view the various islands by cruise boat, take a look at Kazenooto. They offer sunset cruises for a variety of prices. (They're expensive, in my view.) There are cheaper ways, such as a ferry. Let's Go Japan says, "Sunport Takamatsu refers to the development around the port, as well as the port itself, which connects Takamatsu to Inland Sea Islands, Kobe, and Osaka. ... Confirm your plans at the Information Plaza outside JR Takamatsu Station (Japanese). Rates to the islands appear to be about 500 yen (US$5).