Noboribetsu is one of Hokkaido's great onsen towns, though the useful travel centre is not the coastal station but Noboribetsu Onsen in the hills above it. The valley steams, smells of sulfur, and feels more volcanic than polished.
Jigokudani is the headline: a blasted amphitheatre of vents, pale rock, and hot water feeding the baths below. From there, trails lead through forest toward Oyunuma and the Oyunumagawa Natural Footbath, where you can sit beside a warm stream rather than inside a formal bathhouse.
The town also has a theatrical side. Noboribetsu Date Jidaimura recreates an Edo-period village with ninja shows and period streets, while the ropeway to Noboribetsu Bear Park gives wide views toward Lake Kuttara and the Pacific. Noboribetsu is easy to treat as a stop between Sapporo and Hakodate, but it is best if you stay long enough for an evening soak.