Oyunuma Pond is a fascinating volcanic crater lake, a remnant of Mount Hiyori's eruption, and a primary source of the hot spring water for Noboribetsu's hotels. The pond's bottom continuously spews sulfurous spring water at approximately 130°C, creating a perpetually steaming, otherworldly landscape. Its significance lies in showcasing the raw geothermal power that defines the Noboribetsu region, making it a key natural highlight.
Visitors consistently praise the unique visual spectacle of the steaming lake, with its distinctive green-gray-black water and floating yellow sulfur balls. Many highlight the tranquil atmosphere, especially compared to the more crowded Jigokudani, and the opportunity for excellent photography. The natural footbath along the Oyunuma River is a major draw, described as a relaxing and unique experience, particularly after a hike. Reviewers frequently mention the strong sulfur smell, which is part of the authentic volcanic experience, and the well-maintained, scenic hiking trails connecting Oyunuma to other attractions.
To make the most of your visit, allocate 1 to 2 hours, especially if you plan to enjoy the footbath. The best time to visit is during autumn for the vibrant foliage or in winter for a dramatic contrast of steam against snow. Bring comfortable, sturdy shoes suitable for hiking, as some trails can be muddy or slippery, especially in wet or snowy conditions. If you plan to use the footbath, bring a small towel. Seat cushions are available at the footbath but are limited, so consider bringing your own or being prepared to wait. While the pond itself is too hot to touch, the footbath offers a safe way to experience the mineral-rich waters. Parking is available for 500 yen, which often covers parking at Jigokudani as well, making it cost-effective if visiting both by car.
Oyunuma Pond is accessible by car, with a dedicated parking lot (500 yen fee, often shared with Jigokudani). Alternatively, it's a popular and scenic walk from Jigokudani (Hell Valley), taking approximately 15-30 minutes uphill. The path is well-marked but can be steep and slippery in places, especially after rain or snow. Some reviewers suggest taking a bus to the Ashiyu Natural Footbath first, then following the hiking path to Oyunuma. For those with mobility issues, driving directly to the Oyunuma parking lot is recommended, as the platform overlooking the pond is a short walk from there. Public transport options from Noboribetsu Onsen town generally involve buses that stop near Jigokudani, from where you can walk.
Common complaints include the strong sulfur smell, which some find overpowering, and the potential for muddy or slippery trails, particularly in adverse weather. To mitigate these, consider visiting on a dry day and wearing appropriate footwear. While the lake itself is impressive, some visitors find it less spectacular than Jigokudani if viewed in isolation. Combining it with the footbath and the scenic hike from Jigokudani significantly enhances the experience.
