Hokkaido Official Tourism Site HOKKAIDO LOVE!

Lake Toyoni is a rare natural wonder hidden deep within lush ancient forests. Viewed from above, its waters form a striking heart shape—a secluded sanctuary in Erimo where untouched nature still thrives.

The only natural lake within Hidaka Mountains National Park, Lake Toyoni spans roughly 1km in circumference and reaches depths of up to 18m. Known locally as “Batei-ko” (Horseshoe Lake) for its unique contours, the lake is surrounded by an atmosphere of profound tranquility.

Stepping into the dense woodland, visitors are embraced by cool, crisp air and the refreshing scent of pine and earth. If you listen closely, you may hear the sharp call of the Ezo pika, a rare survivor from the Ice Age, echoing through the silence and adding to the mystery of this hidden landscape.

A 1km walking trail circles the lake, revealing the beauty of every season. Summer brings deep green forests, while autumn transforms the surrounding hills into brilliant shades of crimson and gold reflected across the mirror-like water. In winter, the landscape becomes a silent, ethereal world of snow and white light.

Although the lake’s famous heart shape can only be seen from the sky, the experience on the ground is equally unforgettable. Watching fish glide through crystal-clear water while feeling the ancient pulse of the forest creates a rare sense of connection with nature. At Lake Toyoni, time seems to slow down, inviting visitors to rediscover the quiet beauty of the wild.