Turtle Island rises from the sea about 10 kilometers off the coast of Toucheng in Yilan County. It is a volcanic island that sits alone in the sea and is shaped, as its name implies, like a floating turtle. The island features mountain peaks, sea-eroded caves, a lake, special cliff vegetation, and rich marine ecology resources; it is also a fine place for watching the sun rise and set, and it has become a hot tourist spot in recent years because of the large pods of whales and dolphins that frequently appear in the waters nearby.

The island was known far and near, as early as the Qing dynasty, for its "eight scenic wonders," and "sunrise at Turtle Island" has been known as the foremost of the eight scenic attractions of Lanyang. The island's eight scenes are "sunrise at Turtle Island," "sulfur mists of Turtle Island," "sheer cliffs of Turtle Island," "eggs of the turtle," "divine turtle wagging its tail," "divine turtle wearing a hat," "stalactites and stalagmites in Eyeglass Cave," and "upwelling underwater hot springs." These sights change as they are viewed under different conditions of location, weather, and tides, and this is where much of their allure lies.

The waters around Turtle Island are relatively level and shallow to a distance of two to three nautical miles. Many species of fish school here, making this one of Taiwan's three most important fishing grounds as well as the main site in Yilan county for whale- and dolphin-watching. To observe the cetaceans here you have to get a boat at Wushi Harbor; but the service of the boats available there is different, so take care with your choice of whale-watching boat. The main cetacean species you can see here are spinner dolphins, bottle-nosed dolphins, small killer whales, and false killer whales, and boats normally wait on the surface for an hour to an hour and a half to see them. The best season for this activity is April through the end of August; so if you are interested in observing these friendly sea creatures, this is an opportunity not to be missed.