Okunoyu (Noboribetsu Onsen)

Okunoyu is one of the many hot spring sources that make up the famous Noboribetsu Onsen, known for its diverse mineral-rich waters. This striking site is part of the explosion crater remnants of the still-active Mt. Hiyoriyama.

From the cone-shaped basin at the bottom—called a fuki—gray-black sulfur springs erupt violently, creating the image of a boiling cauldron. The surface temperature of the pond reaches between 75°C and 85°C, and the powerful bursts near the front and center are especially impressive.
Surrounded by rising steam and the strong scent of sulfur, visitors can fully immerse themselves in the unique atmosphere of a hot spring area.

Located within walking distance from Jigokudani (Hell Valley) and Oyunuma, the area is equipped with walking trails, allowing guests to enjoy scenic strolls and forest bathing as they explore this natural wonder.