The third largest caldera lake in Japan

The beautiful "Lake Toya" is the central lake of the Shikotsu-Toya National Park and the third largest caldera lake in Japan after Lake Kussharo and Lake Shikotsu in Hokkaido. It is the northernmost ice-free lake with a circumference of 43 km (road circumference of 36 km), an elevation of 84 m above sea level, an area of 70.7 km2, and an average depth of 117 m. In recent years, when the weather has been severely cold, ice formation can be seen in some parts of the lake.

The four islands in the center of the lake (Oshima, Bentenjima, Kannonjima, and Manjujima) are said to be solidified lava domes that were raised by eruptive activity at the bottom of the lake about 50,000 years ago and are collectively called Nakajima. Yotei to the north of Lake Toya, and Mt. Usu and Mt. Showa Shinzan, both well-known volcanoes, to the south, offering a variety of views throughout the four seasons.