Hokkaido Official Tourism Site HOKKAIDO LOVE!

This caldera lake was created by an eruption about 150,000 years ago. The lake is dotted with four islands: Oshima, Kojima, Yaitaijima, and Chuuluijima. Surrounded by the mountains of Mt. Female Akan and Mt. Male Akan, the lake is rich in nature with Lake Akan Onsen hot springs bubbling up along the southern shore of the lake.

Lake Akan has its own unique ecosystem, represented by the “Lake Akan Marimo,” which has been designated a special natural treasure. A type of freshwater green algae, it is characterized by its round, spherical shape.

You can see them at the Marimo Exhibition and Observation Center on Chuului Island, which can be reached by a sightseeing boat, and at the Akankohan Eco Museum Center in the hot spring resort area.

Lake Akan's seasonal scenery is another attraction. The “Ice Breaker Cruise,” which takes visitors on a sightseeing boat through the cracks in the ice that used to cover the lake's surface, is a springtime tradition at Lake Akan that can only be experienced for one week in late April. In summer, visitors can enjoy the great outdoors with activities such as canoeing and trekking. The “Thousand Taimatsu” of the Lake Akan Marimo Festival, held every year from October 8 to 10, creates a fantastic atmosphere as prayer lights are lit in the hot spring resort area. In winter, visitors can enjoy the spectacular view of “frost flowers,” which bloom on the frozen lake only on cold mornings, and “ice bubbles,” a mysterious spectacle of gas rising from the bottom of the lake and trapped in the ice. On the lake covered with thick ice, visitors can enjoy fishing for Japanese smelt and snowboarding. The popular “Fuyukami” event, in which fireworks are set off over the icy lake, is held every year from February to March.