Onsen and baths in Numata

A scenic alkaline 'beauty water' onsen with an outdoor bath overlooking a river terrace and mountain view, attached to Michi-no-Eki Shirasawa with a restaurant and sauna, but marked by paid extras (locker, dryer), a recent price hike, and several complaints of unfriendly front-desk staff.

A mountain-forest day-use onsen with sulfur-scented alkaline water, kakenagashi indoor and outdoor baths, sauna and cold bath, though several reviewers note cleaning happens only weekly.

An aging, budget 24-hour health-land bathhouse and cheap lodging spot near Numata Interchange, with an indoor pool, hot sauna, an underwhelming cold plunge, and a restaurant, but no outdoor bath.

A modern, recently renovated super-sento-style day-use onsen with regular and salt saunas, cold bath, outdoor bath, a well-regarded restaurant/ice-cream counter, and even cottage camping/glamping, but paid for cash-only and marked by repeated complaints of inconsistent, sometimes rude front-of-house service.

A day-use-only sulfur-spring bathhouse at Oigami Onsen with one indoor bath and three outdoor baths (including a rose-petal bath and a waterfall bath), garden and bamboo-grove views, a restaurant, and paid non-refundable changing-room lockers.

A modern, resort-style day-use hot spring complex near Numata with indoor and outdoor alkaline baths, a small dry sauna, a cold plunge, an on-site restaurant, and a reservable private bath.

A slick alkaline kakenagashi bath attached to a golf course and hotel near Numata, with sauna, cold bath, ¥1,000 admission, and a smooth 'bijin-no-yu' feel, though day-use visitors should bring their own towel and the restaurant's lunch service is unreliable.

An old-fashioned, no-frills ryokan near Oze with source-fed water and no outdoor bath, praised for skin-smoothing water but showing its age in maintenance and amenities.

Baths that admit you without an overnight stay

Rotenburo, confirmed by visitors

Gensen kakenagashi, not recirculated

Often with a cold plunge