What to know
Lake Shikotsu (支笏湖) and nearby Lake Toya are the two main highlights of Shikotsu-Toya National Park. Both are caldera lakes formed by volcanic collapse.
Most of Lake Shikotsu remains undeveloped except for Shikotsu Kohan, a small tourist town with a visitor center and some accommodations on the western shore. From here, visitors can rent boats, bicycles, or scuba gear, or join a sightseeing cruise on glass-bottomed or speed boats from late April to early November.
Lake Shikotsu is surrounded by mountains, including Mount Tarumae, one of Japan's most active volcanoes, which last erupted in 1981. The mountain can be climbed in a steep but short ascent of under an hour, offering impressive views of the barren crater and the lake. A two-hour loop around the crater is possible, but entering the crater is prohibited due to toxic gases. The trailhead is accessible by car from late May to October, but there is no public transport.
On the northern shore, Marukoma Onsen is a ryokan with unique hot spring baths open to non-guests on certain days. Some baths are right on the lakeshore, connected by small canals that allow water exchange between the hot pools and the cool lake. The bath water level fluctuates with the lake and can be unusually high for onsen pools outside winter. The ryokan also has conventional gender-segregated hot spring pools.
A rental car is the best way to explore the Shikotsu area. Buses are infrequent, and the Mount Tarumae trailhead is not served by public transport. The lake is a 40-minute drive from Shin-Chitose Airport, 80 minutes from central Sapporo, or an hour from Lake Toya.
From Shin-Chitose Airport, buses go to Shikotsu Kohan (1 hour, 1260 yen one way, every 2-3 hours), stopping at Chitose Station en route. The trip from Chitose Station to Shikotsu Kohan takes about 45 minutes and costs 1140 yen. The direct bus from Sapporo to Lake Shikotsu was discontinued in 2010.
There is no direct public transport between Lake Toya and Lake Shikotsu.