Lake Shikotsu

Formed approximately 40,000 years ago by volcanic activity, Lake Shikotsu is a caldera lake with a circumference of about 40 kilometers and a maximum depth of 360 meters, making it the second deepest lake in Japan. Its low nutrient content and minimal plankton growth result in exceptional water clarity, earning it a reputation as one of Japan’s clearest lakes. The way the water shimmers a brilliant blue under sunlight is affectionately known as “Shikotsu Blue.”

Famed peaks surround the lake including Mt. Eniwa, Mt. Fuppushi, and Mt. Tarumae, all exceeding 1,000 meters in elevation. Enveloped by pristine forests, the lake lies within Shikotsu-Toya National Park, a haven of natural beauty. Each season offers a different face of nature: vibrant spring blooms, fiery autumn foliage, and serene snow-covered landscapes in winter. The area also offers a variety of outdoor activities including diving and fishing. One of the most popular is canoeing, made possible year-round thanks to the lake’s consistent temperature of 4°C, which prevents it from freezing even in winter. Gliding across the lake’s crystal-clear surface feels almost like floating in midair.

On the lakeshore, you’ll find a hot spring resort area with accommodations and eateries serving himemasu (kokanee salmon), a local delicacy raised in the lake’s pristine waters. Before exploring, consider stopping by the lakeside Visitor Center to learn more about the lake’s natural history and ecology.