Lake Toya, which is situated in the southwestern part of Hokkaido, belongs to Shikotsu- Toya National Park. This caldera lake lies 11km east and west, 9km south and north and measuring 43km around.
There are big and small four islands called Nakajima in the middle of the lake, and on it is the Toyako Forest Museum, which is a part of the sightseeing boat route. Trout and smelt fishing are very popular sports in and around the lake. There are also fully facilitated camping sites.