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.
A Meiji-era inn at the entrance to the Jigokudani Monkey Park, famous worldwide for wild macaques that climb into its rotenburo in winter. Day bathing is only 12:00–15:00, so most visitors combine it with the monkey park. It's a 30-minute mountain trail from Shibu Onsen — wear grippy shoes in winter.
In the Hakkoda mountains, bathing since 1684 and Japan's first National Recuperation Onsen. A vast all-cypress mixed bath hall (about 260 m²) fed by four sources. Women-only hour 8–9 am daily; bathing garments sold on site.
The signature inn of Shirahone, famous for milky-white water. Its highlight is a large mixed-gender open-air bath — the water is so opaque that women find it comfortable. Day use at midday only.
A five-minute ride down a 42-degree cable car to the bottom of the Iya gorge, where a self-flowing bath sits beside the river. Day use 7:30–17:00, cable car included. A member of the Secret Onsen Preservation Society.
A free foot bath in an actual river of hot spring water flowing out of Ōyunuma pond, at the end of a forest boardwalk. The perfect finish to a Jigokudani walk. Daylight hours; the trail may close in deep snow.
A family-run bathhouse from 1955 tucked into a residential block: a three-person tub, a Mt. Fuji tile mural and free-flowing water for ¥300. Bring soap and towel — this is a neighbourhood bath, not a tourist spot.
The 1,300-year-old birthplace of Nasu Onsen. Inside the wooden bathhouse, tubs are graded from 41 to 48°C, all fed with milky, strongly acidic sulfur water. No showers, no soap — start with the traditional head-dousing ritual.
A historic cure-bath in the hills a short way from Unzen's main street, said to have hosted Siebold and Yoshida Shōin. An octagonal wooden bathhouse with milky sulfur water cooled from a 90°C source. No open-air bath, but Unzen's finest water.
A huge boulder-lined mixed open-air bath on the Gamata riverbed, looking up at the Northern Alps and a suspension bridge. Open only late April to the end of October; swimwear or bathing gowns allowed. Pay a cleaning donation of about ¥300.
A rustic day-onsen near the Shinhotaka trailhead with a canteen where model trains run past your table. The open-air bath faces Mt. Shakujō and Mt. Kasa, and fills with hikers fresh off the mountain. Closes in winter depending on snow.
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.
Five minutes' drive beyond the village in Oku-Kurokawa, this inn's riverside open-air bath 'Yūkoku-no-yu' is often called the finest in Kurokawa. Day use 10 am–3 pm, ¥600 (or with the ¥1,500 hopping pass); private baths ¥2,500/50 min until 8 pm.
At 1,800 m in Manza, four private sources feed eight open-air pools of milky, yellow and clear water — the famous 'Sekitei' rock-garden baths. Mixed bathing, but gowns or wrapped towels are required and there is a women-only pool. Day use 11 am–6 pm (last 5 pm), ¥1,700.
Right at the Shirahone bus stop, gender-separated public open-air pools built against the gorge cliff. Milky bicarbonate water for ¥700; no washing area, pure rustic soaking. Closed late Nov–late Apr and Tuesdays. Handy before or after Awa-no-yu's short day-use window.
A natural open-air bath on the Asahi River gravel bed right below Yubara Dam, where water bubbles up through the riverbed itself — ranked the 'western grand champion' of Japan's rotenburo. Three pools at different temperatures; mixed, free and open 24 hours. Only a simple changing hut, so women are advised to wear a bathing garment (sold and rented in town). Closed Wednesday mornings for cleaning. Photography strictly forbidden.
A wooden toji (therapeutic stay) inn over 200 years old on the Toyosawa River in the Hanamaki-Minami onsen area, once frequented by poet Kenji Miyazawa. Its signature is 'Osawa-no-yu', a mixed open-air bath jutting over the river, with women-only hours. Day bathing from 7 am; ¥700 covers three baths. Many linger for lunch and sake at the 'Yahagi' dining room. Free shuttle from Hanamaki Station.
At the southern tip of Nara, directly opposite the Totsukawa Onsen bus center where Japan's longest local bus route (Yagi–Shingu) stops. A small all-timber bathhouse looking down on the Futatsuno dam lake. The whole village has pledged 'free-flowing spring water only', so nothing is recirculated. Free foot bath, hand bath and drinking fountain. Combine with the Kumano Kodo and Tanize suspension bridge.
The communal bath of Yunotsu, once the shipping port for the World Heritage Iwami Ginzan silver mine. Rated a perfect 'all fives' by the Japan Spa Association, it is 100% free-flowing, and iron-rich mineral deposits coat the tub in thick brown crusts. Next door is 'Shin-yu', a Western-style wooden building from 1919 whose retro café and rooftop terrace are open to bathers. ¥600. The whole street is a preserved historic district.
A wooden ryokan founded in 1841 on the Toyosawa River at the far end of the Hanamaki onsen villages. Its signature is 'Hakuen-no-yu', a self-welling rock pool about 1.25 m deep that you stand in — billed as Japan's deepest rock bath. Five springs feed four bathhouses, all 100% free-flowing. Day use ¥800, 10:00–21:00. Hakuen-no-yu is mixed bathing with women-only hours. Free shuttle from Hanamaki Station by reservation.
A village-run public bath on the shore of Futatsuno Dam lake in Totsukawa, the village that declared all its baths 100% free-flowing. Attached to a seniors' centre, it's plain but pours 70°C bicarbonate-chloride water straight in with no recirculation. Handy on Tuesdays when nearby Iori-no-yu is closed. ¥600, 9:00–21:00, closed only Jan 1–2. Five minutes' walk from Totsukawa-Onsen bus stop.
The source bath of Ryujin Onsen, counted with Yunokawa and Kawanaka among Japan's 'three beauty baths'. It stands on the Hidaka River deep in the Kii mountains, with a cypress indoor bath and a rock rotenburo overlooking the stream. The silky bicarbonate water is famous for leaving skin smooth. ¥800, 7:00–21:00, open daily. An hour by car from Koyasan via the Koya-Ryujin Skyline, or about 80 minutes by bus from Kii-Tanabe.
A lone inn in a primeval beech forest on the southern flank of Mt. Hakkoda. Spring water wells up directly through the gaps in the hiba-cypress boards on the tub floor — 'free-welling', so you bathe in water that has never touched air, a rarity even in Japan. The all-hiba 'Kyuan-no-yu' bathhouse from 1918 is magnificent. Day use 10:00–15:00, ¥1,000; may close early when busy. Combine with the hour-long trail around Tsuta-numa pond, famous for autumn colour. Closed in winter.
Thirty minutes by car from Fukushima city, the communal bath of Takayu Onsen at 750 m on Mt. Azuma. Every bath is open-air, filled with milky-white sulfur water that is neither diluted nor heated. There's a timber men's bath, a rock women's bath and a reservable private rotenburo. A ¥500 gateway to a spa town that has kept its water free-flowing for 400 years. Closed Thursdays; one-hour limit. At the foot of the Bandai-Azuma Skyline — ideal with an autumn drive.
Five minutes by car from the Kazurabashi vine bridge, this popular Iya inn is famous for its 'sky open-air bath' reached by private cable car. Day bathing (¥1,200) runs 10:30–16:00; the goemon cauldron baths are for overnight guests only. A free sky footbath on the viewing deck is spectacular on mornings with a sea of clouds. With Hotel Iya Onsen it forms Iya's pair of 'cable-car onsen', ideal for a break while touring the valley.
The village-run public bath of Tōsenji Onsen, the oldest spring in Totsukawa. pH 9.1 alkaline sulfur water flows fresh from the source even through the taps, leaving a faint sulfur scent and slippery skin. Just a stone open-air bath facing the gorge and an indoor tub—simple and ¥600. Handy on Route 168 en route to the Tanize suspension bridge or Kumano Hongū Taisha.
A solitary inn on the Hinoji River in the Shimanto headwaters. Its viscous, highly alkaline water has been revered as a healing spring since the Edo period, and a day soak is a modest ¥700. Enjoy the open-air bath above the stream or book a private bath. Open late, 10:30–21:00, and 30 minutes by car from Kubokawa Station—ideal after canoeing or cycling the Shimanto.
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 lone inn at 1,300 m, the last stop in the Nasu hot-spring range. Spring water gushes out behind the building in such volume that it forms a river, dammed into the vast outdoor 'Kawa-no-yu' — nothing else like it in Japan. Mixed bathing since the inn's founding, but bathing wear is included so beginners can relax. Day use is limited to three hours (reception 11:30–14:30), ¥1,300 with face towel and bathing wear. The outdoor bath closes in bad weather or for cleaning, so phone ahead. Autumn colour and snow seasons are the draw.
The highlight of any Gonō Line journey: a lone inn famous nationwide for its 'seaside open-air bath' set right at the water's edge of the Sea of Japan. Iron-rich chloride water, rust-red and cloudy, seems to merge with sea and sky. Day use is ¥600 — the seaside bath 8:00–16:00 (last entry 15:30), the main-building indoor 'Kogane-no-yu' 8:00–20:00. The mixed outdoor bath allows bathing wear (rental fee); a women-only outdoor bath sits alongside. Sunset soaks are for overnight guests only, so stay if you want one of Japan's 100 best sunsets from the tub.
The only hot spring inscribed as a World Heritage Site that you can actually bathe in, listed together with the Kumano Kodo pilgrimage routes. A tiny hut over the stream in Yunomine — said to be Japan's oldest onsen at 1,800 years — shelters a tub hollowed from natural rock that fits two adults. The sulfurous water is said to change colour seven times a day and served pilgrims for ritual purification. Private 30-minute slots, ¥800, sign up at the public bathhouse (6:00–21:00). Waits of several hours are common on holidays; boil onsen eggs in the hot-spring trough while you wait.
At Kawayu, where 73°C spring water bubbles up through the bed of the Ōtō River, a giant outdoor bath is created every December to February by damming the river. Roughly 50 by 15 metres — big enough for 'a thousand people', as the name says — it's tempered to perfection by the river's cold flow. Free (donation box), 6:30–22:00, swimwear required, open to everyone. Bathing is suspended in bad weather or high water and opening dates shift from year to year. In summer you can dig your own pool in the gravel. Combine with Yunomine and Watarase for the three Hongu baths.
One of Tōhoku's highest hot springs, at 1,126 m on the northern slopes of Mt Kurikoma. Some 6,000 litres a minute flow like a stream; the strongly acidic alum-vitriol water (pH around 2) carries white mineral flakes and tingles on the skin. The famous big open-air Dainichi-yu is an open, rock-backed pool; day use 6:00–21:00 (until 20:00 on Wednesdays), ¥900. The indoor baths and the 'oiran' steam bath run 9:00–16:00. Because of the altitude, the road and the onsen close in winter (early November to early May). About 95 minutes by bus from Ichinoseki Station to the Sukawa Onsen terminus; it is also the Kurikoma trailhead, busiest in autumn colour season (late Sept–early Oct).
A lone inn with its own spring near Ōmi-Shirahama, the pine-fringed white-sand beach on Lake Biwa's west shore. The simple carbonated iron spring (a cold mineral spring, heated) turns tea-brown on contact with air and is locally prized as a skin-beautifying bath that warms to the core. Drop-in bathing 9:00–20:00 (last entry 19:30), a modest ¥700; closed Mondays. The open-air bath is private-hire only (from ¥3,000 per 50 min), good for families and couples. The restaurant (11:00–20:00) serves Ōmi beef and lake fish. Five minutes by car from JR Ōmi-Takashima Station — on the way back from Shirahige Shrine's lake torii or the metasequoia avenue. Day use may be unavailable when groups are staying, so phone ahead.
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.
The town-run bathhouse at the heart of Toyotomi Onsen, Japan's northernmost hot-spring village, an hour by car from Wakkanai airport. The spring was struck during oil exploration in 1926 and still carries traces of petroleum — a rarity worldwide, with an oily smell and slippery feel. It is famed as a 'miracle bath' that draws people from across Japan seeking relief from atopic dermatitis and psoriasis. Besides the general bath there is a cooler cure bath for long soaks. Admission is a cheap ¥510; open 10:00–21:00 (last entry 20:30), closed every other Thursday. The canteen serves jingisukan lamb and set meals. Fit it into a far-north drive with the Sarobetsu wetlands and views of Mt Rishiri. About 10 minutes by bus from JR Toyotomi Station.
An open-air-only public bath on the gravel banks of the Gamata River at Tochio Onsen in the Okuhida valley. The rock-ringed men's and women's pools have no screen on the river side, so the rushing Gamata and the Northern Alps fill the view — starry skies at night, snow scenes in winter, wild Okuhida all year. Free-flowing simple spring water; there are changing huts but no reception — drop a donation (about ¥300) in the wooden box at the entrance. Open 8:00–22:00 (from 12:00 Mon, Wed and Fri for cleaning); no closing days, but suspended when the river is high. Bring a towel. An easy stop between the Shinhotaka Ropeway and Hirayu, or a night soak for anyone staying in Tochio's inns.
A wooden inn founded in 1789 at Kamasaki Onsen, a mountain cure spa in Shiroishi, Miyagi, where villagers are said to have struck hot water with the tip of a sickle more than 600 years ago. Its iron-bearing sulphate water, known as the 'medicinal bath of Ōu', turns tea-brown and has long been trusted for cuts and bruises. Gleaming dark corridors, glass shōji and traces of the old self-catering cure wing make it irresistible to lovers of retro Japan. Day use 11:00–14:00, ¥800; bring a towel. Fifteen minutes by car from Shiroishi-Zaō Station — a convenient stop with Shiroishi Castle, the Yajirō kokeshi village or the start of the Zaō Echo Line. Day bathing is sometimes suspended when busy or for cleaning, so phone ahead.
A solitary forest inn five minutes by car from central Kurokawa, where the only sound is the headwaters of the Chikugo River. On roughly 10,000 m² of grounds sit the mixed open-air Moyai-no-yu and the women-only Shiki-no-yu, fed free-flowing from two private springs; the indoor bath has a faint blue tint. Day use covers the open-air baths only, 08:30–21:00, ¥600 for adults, and Kurokawa's 'nyūtō tegata' bath-hopping pass (¥1,500 for three baths) is accepted, so pairing it with inns in the village is the classic plan. There is a free rest corner after bathing. Closures are irregular — phone ahead.
At 1,800 m in Manza Onsen — said to have the highest sulphur content in Japan — this is the most rustic of the old spa-cure inns. The wooden bathhouse holds just one indoor tub per gender, but the milky acidic sulphur water is thick and hot enough to leave you drowsy afterwards. It is known for its 'Sarunokoshikake-yu', in which extract of a bracket fungus has long been added to the water. Day use 10:00–16:00, ¥700 for adults, towels sold for ¥250. For onsen fans who want an old-school cure-bath feel amid Manza's big resort hotels. The building has tilted due to ground subsidence, so phone ahead to confirm it is operating. About 40 minutes by bus from Manza-Kazawaguchi Station.
About 12 minutes on foot from Murodō terminal, the hub of the Tateyama-Kurobe Alpine Route, this inn at 2,410 m is Japan's highest hot-spring lodging. Milky acidic sulphur water piped from Jigokudani flows 100% free, and outside the window is another world: the 3,000-metre Tateyama range and the volcanic lake Mikurigaike. The bath is indoor only; day use 09:00–16:00, ¥1,100 for adults. The café's blueberry soft-serve and curry are favourites. Open only during the mountain season, mid-April to late November; closed in winter. Especially busy during the Snow Corridor (Apr–Jun) and autumn colours (late Sep–early Oct). With the altitude and strong water, keep your soak short.
A lone inn of the Japan Association of Secluded Hot Springs, deep in Hachimantai National Park amid beech and oak forest. The open-air bath is an unusual greenish milky white — free-flowing simple hydrogen-sulphide water — with a mixed outdoor bath, a women-only outdoor bath and separate indoor baths; from the rotenburo you can see the steam of Japan's first geothermal power station. Day use 08:30–19:00 (last entry 18:00), ¥700 for adults, or ¥900 with hall rest 10:00–15:00. Open year-round, and the snow-buried outdoor bath in winter is the highlight. About 1 h 50 min by Iwate Kenpoku bus from Morioka Station to the Matsukawa Onsen terminus.
The communal bath of Maga Onsen, a tiny hamlet of stone stairways on a slope above a tributary of the Asahi River in the Yubara Onsen area. Legend says a defeated warrior healed his wounds here some 700 years ago. The star is the 'Makuyu', a mixed rock bath of about 1.6 × 2 m and 1.2 m deep, so you soak standing up — often called Japan's smallest mixed bath — with lukewarm 39°C water bubbling up through cracks in the rock floor. The men's and women's baths connect to it and cost ¥250; the Makuyu is ¥400 (max 8 people, one hour) and a private bath ¥1,300 for up to three. Open 08:00–21:00 (last entry 20:10), closed Tuesdays (open on holidays). No towels allowed in the mixed bath, so be prepared. About 20 minutes by car from Chūgoku-Katsuyama Station.
A hidden spring on the site of an old copper mine in the hills of Kumano, Mie. The abundant water is entirely free-flowing with no dilution or heating; the clear sodium-chloride spring warms you to the core. The cedar-scented bathhouse, rebuilt in 2015, has an indoor bath, an open-air area with standing, half-body and lying baths, and a private bath for ¥1,080 per hour. Admission ¥600 for adults, open 09:00–21:00 (last entry 20:15), irregular closures. A trolley train through the old mine tunnel (about 10 minutes) links it with Iruka Onsen Seiryūsō and is a famous ride in itself — but as of 2026 it is suspended for safety inspections, so check ahead. Half-price admission on the 26th of each month. About 40 minutes by car from Kumano-Ōdomari IC.
In the town centre of Ibusuki, famous for its sand baths, this is one of the oldest communal baths, dating from 1882. Locals call it 'Muran-yu'. Its pride is the wooden bathhouse and the spring that wells up straight through the floor of the tub; there are no taps — you scoop the emerging water with a bucket to rinse, the old way — and there are two tubs, hot and lukewarm. The sodium-chloride water is strongly salty in true Ibusuki fashion and keeps you warm for ages. Adults drop ¥350 into the unattended fee box; open 08:00–22:00. No soap provided, so bring your own. About 13 minutes on foot from Ibusuki Station. For onsen fans who want a 'real locals' bath' after the Saraku sand-bath hall; entry may not be possible during cleaning or crowding, so check closure days in advance.
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.
A free, gender-separated open-air bath at the top of Tsubame Onsen, a trailhead village at about 1,100 m on Mt Myōkō. Five minutes up a mountain path from the village you find only a simple plank changing hut and a rock tub, where flakes of 'yunohana' drift in milky sulphur water. Known as a 'triple beauty bath' for combining sulphur, bicarbonate and sulphate, it faces the flanks of Myōkō. Free of charge from sunrise to sunset, open April to November (closed in winter; boots needed while snow lingers); no bathing on Monday and Friday mornings for cleaning. Fifteen minutes further along the gorge is the mixed 'Kawara-no-yu' (Jul–Nov). No soap allowed and minimal changing space, so follow local etiquette. Walk from the terminus of the bus (about 21 min) from Sekiyama Station.
A lone inn in the hills of Kitagawa, a 'yuzu village' of some 1,300 people in eastern Kōchi. Its spring, known for over 80 years, is loved locally as silky 'beauty water', and in 2018 the inn was completely rebuilt as Japan's first CLT-construction hot-spring building, using timber from the village. The wood-wrapped main bath, open-air bath and family bath are all 100% source water. Day bathing: adults ¥700, children ¥350, 11:00–21:00 (last entry 20:30), closed Tuesdays. Private baths cost ¥2,200 per group for 50 minutes on top of admission. There is a restaurant serving yuzu dishes, and the Nakaoka Shintarō museum and Monet's Garden Marmottan are nearby — a good stop on a drive toward Cape Muroto. About 20 minutes by car from Route 55; 14 rooms in three types.
The highest hot-spring inn in Tōhoku, at 1,400 m near the top of the Hachimantai Aspite Line. It opens only from Golden Week to late October; in winter it is buried in snow. Five mixed open-air baths scattered down the slope (plus a women-only open-air bath and separate indoor baths) are fed by sulphur water bubbling up directly through the ground, milky white, and the trademark is smearing the mud from the bottom on your skin as a 'mud pack'. Below spread Mt Iwate and a sea of forest; at dawn, cloud seas and sunrise — truly a bath above the clouds. Simple sulphur water at temperatures from tepid to hot. Day bathing: adults ¥650, children ¥350, with a long 08:00–18:00 window, busy with hikers back from the Hachimantai summit trail. The open-air baths are mixed, so bathing garments and wrap towels are allowed. About 2 hours by bus from Morioka Station or 40 minutes by car from Matsuo-Hachimantai IC. Mobile reception is poor.
The lone inn at Gokuraku Onsen, in the hills of Takaharu on the eastern foot of the Kirishima range, with water distinctive enough to be listed among Japan's 'hundred famous springs'. It is a carbonated iron spring (carbon dioxide-iron-calcium-bicarbonate), and the speciality is alternating between the free-flowing tubs, turned rust-red on contact with air, and a 'source cold bath' filled with the highly carbonated mineral water straight from the ground. Sitting in the cold fizzing water as tiny bubbles cling to your skin, then returning to the warm bath, is a routine sauna lovers adore. There is also an open-air bath, a sauna and a reservable private bath. Day bathing: adults ¥600, children ¥250, with long hours from 07:00 to 21:00 (last entry 20:30), except Wednesdays when it pauses 10:00–15:00 for cleaning. A dining room serves Kyushu mountain-and-river cuisine, and private rest rooms and overnight stays suit a cure-style visit. About 15 minutes by car from JR Takaharu Station or Takaharu IC. A hidden gem for Ebino Plateau and Kirishima trips.
A cure-bath founded in the Meiji era, tucked in the hills of Misato, Shimane, up a tributary of the Gō River. The spring bubbles up directly through gaps in the wooden floor of the tub — 'footspring' water that onsen devotees rank among the finest sources in western Japan. The carbonated iron-bicarbonate water is tepid at around 34 °C, faintly yellow-brown, and coats the body in tiny bubbles. There is one small wooden tub each for men and women, no washing area, soap and shampoo are forbidden, and bathing is limited to an hour: this is a place purely for soaking. Afterwards you can warm up in a heated goemon iron-kettle bath. Adults ¥500; open 08:00–18:00 April–October (last entry 17:00) and 08:00–17:00 November–March (last entry 16:00), closed Thursdays. Room rest is available. With the Sankō rail line gone, driving is realistic: about 1 hour from JR Gōtsu Station or 50 minutes from Ōasa IC on the Hamada Expressway, with a narrow mountain road at the end. Not for those wanting facilities, but unforgettable for those who care about the water itself.
A lone hidden spring at the end of a forest road in the hills of Ikarigaseki, Hirakawa, near the Aomori–Akita border. Famed nationwide for its gushing flow — said to be 500 litres a minute — the overflow from the tub streams across the entire washing floor like a river, and the place once topped a fan vote for the best free-flowing bath in Japan. The sodium-calcium-chloride-sulphate water is pale yellow-brown with an iron tang, and the local way to enjoy it is 'todo-ne': lying flat on the floor and letting the running water wash over you like a sea lion. After a long closure it reopened, renovated, in December 2025: day bathing adults ¥600, children ¥200, 09:00–20:30. Lodging is bed-and-breakfast or room only. Pick-ups from Ikarigaseki Station and Yunosawa can be arranged (contact in advance). Facilities are basic and days and hours can change, so check by phone or on the official social media. About 15 minutes by car from JR Ikarigaseki Station or Ikarigaseki IC; beware of deep snow in winter.
A municipal spa retreat in the mountains at the eastern edge of Ōno, Fukui, close to Lake Kuzuryū. Ringed by the clear Kuzuryū River and forested hills, it offers colourless, soft alkaline simple spring water in an indoor bath and an open-air bath overlooking the valley through fresh greenery, autumn colours and deep snow (the outdoor bath may close on winter weekdays). There are a sauna, a tatami rest hall and a restaurant, and the site forms part of the Kuzuryū Hoyō-no-Sato complex with cottages and the Hotel Flairal Izumi next door. Adults from outside the city pay ¥800 (residents ¥700), children from age 3 ¥400 (¥350). Open 10:00–21:00, from 12:00 on Wednesdays; closed Tuesdays (next day if a holiday) and 1 January. About 17 minutes on foot from Echizen-Shimoyama Station on the JR Etsumi-Hoku Line, or right off the Kuzuryū IC on the Chūbu-Jūkan Expressway. An easy stop after the Kuzuryū roadside station, an autumn drive around the lake or a climb of Mt. Arashima.
A day-use hot spring in Jinsekikōgen, a plateau town at 500–700 m in eastern Hiroshima. The source, discovered in 1994 in the Iseki district of former Sanwa, is a rare pH 10.2 strongly alkaline, weakly radioactive cold mineral spring – low in irritants and gentle on the skin. The slightly cloudy, viscous water lifts excess oil and leaves skin smooth, which locals call a 'natural beauty serum'. Inside are an indoor bath, open-air bath, sauna and cold plunge, plus a rock-bed spa, carbonated tub and a private family bath, with a rest area and restaurant. Adults pay ¥900 and children of elementary age or under ¥500; coupon books and a monthly pass keep the regulars coming. Open 10:00–21:00, closed Tuesdays, parking for 20 cars. About an hour by car from central Fukuyama via Route 182, or 2 minutes on foot from the Iseki-naka bus stop. Pair it with Taishaku Gorge, Jinseki beef and stargazing on a drive across the highlands.
A lone hot spring inn at Kamuta in Takaharu, Miyazaki, on the eastern foot of the Kirishima range. A therapeutic bathing spot since the Meiji era, its pride is an extremely carbonated spring with 1,314 mg/kg of free carbon dioxide. Ease into the unheated, chilly carbonated pool and fine bubbles cling to every inch of skin – a concentration said to equal 10–25 bath-fizz tablets. The heated indoor and open-air baths glow golden with iron-rich cloudy water, and alternating between them and the cold spring is the house ritual; a drinking fountain lets you taste the sharply fizzy, iron-flavoured source too. Day bathing costs ¥650 for adults and ¥300 for ages 3–12, 10:00–21:00 (last entry 20:30), closed as a rule on the first and third Wednesdays (subject to change). Day-rest rooms, tatami rooms and detached cottages for overnight stays, and meals of local produce are available. About 10 minutes by car from Takaharu IC on the Miyazaki Expressway, with parking for about 60 cars. Combine it with Kirishima Shrine, a climb of Takachiho-no-mine or the Ebino plateau.
A lone day-bath building among the fields on the outskirts of Nirasaki, north-west of the Kōfu basin, and a nationally known pilgrimage spot for onsen lovers. Nothing is added or altered – no dilution, heating, recirculation or chlorine – and as you settle into the tepid 38°C sodium chloride-bicarbonate spring, your whole body is coated in fine bubbles, said to be among the most abundant in Japan. The faintly greenish-yellow water carries a whisper of sulfur and iron, and the source running from a tap in the bathroom can be drunk (fizzy, iron-tinged). There is no open-air bath or sauna – just one big indoor pool and washing stations, like a sentō – but the windows frame the Yatsugatake and Kayagatake peaks, and the mild water makes an hour disappear. Adults pay ¥600, children ¥300, soap and shampoo provided. Open 10:00–20:00, closed Tuesdays (next day if a holiday) and Fridays, with free parking for 25 cars. About 10 minutes by taxi from Nirasaki Station on the JR Chūō Line or 15 minutes from Nirasaki IC on the Chūō Expressway.
A town-run hot spring inn on the clear Katsuura River in Kamikatsu, Tokushima – the village famous for its 'leaf business' and zero-waste pledge – that welcomes day bathers. The simple sulfur cold spring is heated for the baths and has a faint sulfur scent and a slippery, smoothing feel. The open-air bath faces the stream and looks over fresh greenery, autumn colour and terraced rice fields, with an indoor bath and sauna alongside. Adults (junior-high and up) pay ¥650 and children from 3 to elementary age ¥350; open 10:00–20:00, closed the second Wednesday. The dining room serves Kamikatsu mountain vegetables, Awa-odori chicken and dishes garnished with the village's celebrated 'irodori' leaves, and stays combining the adjacent campground and Kamikatsu tea farms are popular. Free parking for 150 cars, coaches welcome. About 50 minutes (39 km) by car from central Tokushima or 80 minutes from Tokushima IC; by Tokushima Bus on the Kamikatsu line to the Tsukigatani Onsen stop near the terminus. Pair it with the Kashihara rice terraces and the RISE & WIN brewery.
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.
A 400-year-old hot spring inn standing alone deep in the Ogawa river gorge that runs down from the Northern Alps in Asahi, the easternmost town of Toyama. Known as a fertility and therapeutic spa, it offers a circuit of five different baths. The great curiosity is the 'natural cave open-air bath', a dome of travertine built up over centuries from the spring's own mineral deposits and designated a prefectural natural monument – bathing inside it is an experience found nowhere else in Japan. There are also the streamside Renge-no-Yu outdoor bath, a rock bath and a cypress tub, all with free-flowing bicarbonate spring water that keeps you glowing long after. Day bathing runs 9:00–15:00 (reception until 14:30) for ¥1,000 per adult and ¥500 per child, or half price for the outdoor baths only. Irregular closures, and the two outdoor baths shut for winter from 1 December until the mid-April thaw. About 15 minutes by car from Tomari Station on the Ainokaze Toyama Railway, 30 minutes from Kurobe-Unazuki-Onsen Station on the Hokuriku Shinkansen (shuttle for overnight guests) or 15 minutes from Asahi IC. A hidden spring to pair with the Jade Coast and Unazuki on a drive along the Niigata border.