Oyunuma River Natural Footbath

Above Noboribetsu Onsen, hot water spilling from Oyunuma, a steaming crater pond, forms a warm river through the forest, and at one bend, beside the Taisho Jigoku vent, a wooden deck lets you sit with your feet in the current. It is free and unstaffed, and on a cool morning the steam hangs over the water between the trees. Getting there is part of the point.

Walk up from the onsen town through Jigokudani, follow the path past Oyunuma, then take the Oyunuma River trail down to the deck. A LIVE JAPAN writer took about two hours for the whole loop with stops, including steep slopes and long flights of stairs. The water is murky, so you can't see the bottom, and some spots run noticeably hotter than others; test with a hand first.

Parts of the boardwalk have no railings, so keep children close. Bring a small towel and something to sit on, because the deck is often wet. The Kuttara road above Oyunuma closes in winter, and this footbath was shut for a long stretch after 2016, so confirm with the Noboribetsu tourism association before you set out between November and April.

Downside: it is only a footbath, and the walk in has steep, unfenced sections.