The oldest inn in the Nyuto Onsen area, a hidden hot spring dating to the Edo period. The thatched 'Honjin' building and the large milky-white mixed rotenburo are its iconic scene. Day bathing 10:00–15:00; on Mondays the rotenburo is closed for cleaning and only indoor baths are open. Rooms sell out months ahead. From Tazawako Station take the bus, then the inn shuttle from Alpa Komakusa.
The innermost of Nyūtō's seven baths — a cluster of thatched bath huts. Two separate sources feed a mixed open-air pool and gender-separated indoor/outdoor baths of milky sulfur water. Day use 9 am–4 pm, the longest window of the seven; closed mid-November to mid-April.
The most polished of the seven Nyūtō inns, beside the Sendatsu stream and popular with women. Two sources — rusty 'gold' and clear 'silver' — in open-air baths above the rushing river. Day-use reception is short (10:30 am–2 pm), so come early.
A modern cure-bath inn fed by Tamagawa Onsen, Japan's most acidic spring at pH 1.2. The hiba-cypress bathhouse lines up 15 tubs — 100% source, 50% diluted, mildly acidic and more — so you can choose by condition. Day use 10:00–15:00, ¥1,000 (revised April 2026). An indoor stone-slab bath (¥800) is also available, and unlike the original Tamagawa it stays open all winter for snowbound soaking. About 70 min by bus from Tazawako Station.
A single inn at the end of the Nyūtō bus line, wrapped in old-growth beech forest and named for the river crabs once abundant in the nearby stream. Unusually for Nyūtō, the water is clear and colourless — a bicarbonate spring with drifting white flakes and a gentle feel. The signature is Karako-no-yu, a mixed open-air pool some 50 m from the building in the woods, magical in snow season; there are also separate indoor wooden and rock baths. Day use 9:00–16:30, ¥800. Covered by the Yumeguri-chō pass (¥2,500, valid one year) for all seven Nyūtō inns — the classic combo is with Tsuru-no-yu and Taenoyu. About 50 minutes by bus from Tazawako Station to the Nyūtō Onsen stop.
A lone inn in a steaming fumarole field at about 1,000 m on the Akita side of Hachimantai. One of Tōhoku's great cure spas — 'arrive on horseback, leave on your own two feet', as the saying went — it is also famous for its ondol-heated cure wing. The main bathhouse lines up seven kinds of tubs: the signature box steam bath, a mud bath, a cascade bath, a 'volcano bath' and an open-air bath, all fed by milky acidic sulphur water. Day use 10:30–15:00 (last entry 14:00), ¥800 for adults, closed Tuesdays (plus maintenance days). Behind the inn a nature trail loops past mud volcanoes and vents in about 40 minutes. About 1 h 55 min by bus from Tazawako Station on the Hachimantai summit line (usually late Apr–mid-Oct); in winter come by local bus from Kazuno-Hanawa Station or by car.
The representative drop-in bath of the Mizusawa spa cluster on the Tazawako plateau, on the road up to Nyūtō Onsen. Less famous than Nyūtō's hidden inns, it nonetheless runs an abundant sulphur-calcium-magnesium-sulphate-chloride spring free-flowing, and its bluish milky water is praised as 'silky and moisturising'. The standout is an open-air bath about a metre deep in which you soak standing up — one of only two such deep outdoor baths in the area. Men and women each have two indoor and two outdoor baths, and the waterfall massage runs all the time. Adults ¥900, primary-school children and under free; open 10:00–20:00 (building closes 21:00), irregular closures (open through Golden Week, Obon and New Year). Lodging is available, and it makes a good alternative when Nyūtō is crowded or a stop after Tazawako ski slopes or a climb of Mt Akita-Komagatake. About 25 minutes by Ugo Kōtsū bus for Nyūtō Onsen from JR Tazawako Station to 'Mizusawa Onsenkyō', right by the stop; 60 parking spaces.
A day bath inside Alpa Komakusa, the Semboku city complex where buses depart for the 8th station of Mt. Akita-Komagatake. Sharing the building with the mountain information centre and volcano disaster station, it bustles with hikers and Lake Tazawa sightseers. The 'Nature Onsen Hall' has two lookout open-air baths, one of rock and one of hiba cypress, gazing down on the lapis-blue surface of Lake Tazawa – Japan's deepest – and the sweep of the mountains. The milky simple sulfur spring rises from the same range as Nyūtō and Mizusawa onsen and warms a chilled body thoroughly with a soft sulfur scent. Admission is a modest ¥550 for adults and ¥300 for children. Hours are 9:00–19:00 (last entry 18:00) from April to November, 9:30–17:30 (last entry 17:00) from December to March, and 9:00–18:00 on Thursdays and Fridays; open daily except Thursdays from November to April. Rest corner and light meals available, with a large car park. From JR Tazawako Station take the Ugo Kōtsū bus bound for Nyūtō Onsen about 35 minutes to the Alpa Komakusa stop. Perfect for a soak on the way to or from Nyūtō or after climbing Komagatake.