Ask a Japanese traveller to name the country's best hot spring and the answer, more often than any other, is Kusatsu. It sits at 1,200 metres in the mountains of Gunma Prefecture, north-west of Tokyo, and pours out more hot-spring water than any other resort in Japan — strongly acidic, sulphurous, so hot it has to be cooled by hand before anyone can bathe. It is also a proper town, with a centre built around the steaming Yubatake, a nightlife of yukata-clad strolling, and a full range of inns from wooden classics to modern resorts. For an agent who needs an onsen night that is unmistakably the onsen, and who can spare the extra hour beyond Hakone, Kusatsu is the answer.
The Yubatake and the yumomi
The Yubatake — the "hot-water field" — is the heart of Kusatsu: a steaming terrace in the town square where the spring water runs through wooden channels to cool before it is piped to the bathhouses. At night, lit and misting into the cold, it is one of Japan's most atmospheric town centres. Next to it the Netsunoyu hall stages the yumomi several times a day: women in traditional dress stirring the water with long wooden paddles to cool it, singing as they work, because adding cold water would dilute the spring's mineral strength. Visitors can try the paddles. It is theatre, but it is theatre with a purpose, and it explains the town in fifteen minutes.
The public baths are the other half of the experience. Sainokawara, an enormous open-air bath in a rocky river valley on the edge of town, is the one to send clients to; the free neighbourhood bathhouses are for the adventurous. Our onsen etiquette guide prepares first-timers, and our tattoo guide covers the question that comes up on every file.
Where to stay and what to eat
Kusatsu has a full spectrum of inns, which is exactly what makes it useful to the trade. At the top are historic wooden ryokan with private open-air baths and kaiseki of real quality; in the middle, comfortable resort hotels that take groups and coaches without fuss; and for FIT clients on a budget, small family inns a few minutes' walk from the Yubatake. Every one draws its water from the same acidic source, so the bath is never the compromise. We contract across the range — see our ryokan and onsen services and the luxury ryokan guide for how we match inn to client.
Gunma is inland mountain country and eats like it: onsen manju steamed buns sold hot on the streets, mountain vegetables, Joshu beef, and the prefecture's flour culture of okkirikomi wide noodles and yaki-manju grilled buns. The town is easy on a walking evening — yukata, wooden sandals, a manju in hand, the Yubatake steaming below.
Beyond Kusatsu: the rest of Gunma
- Ikaho Onsen, closer to Tokyo, is built up a famous stone staircase of 365 steps lined with inns and shops, with iron-rich "golden" water; smaller and more compact than Kusatsu, it suits a one-night stop.
- Minakami is Gunma's outdoor base — white-water rafting and canyoning in summer, skiing in winter, and the Takaragawa Onsen, whose vast riverside open-air baths are among the most photographed in Japan. It fits the outdoor adventure file.
- The Tomioka Silk Mill, a UNESCO World Heritage site, is the 1872 factory that industrialised Japan's silk trade — a well-preserved, well-explained site on the way to or from the mountains that rewards a guided hour; see our World Heritage guide.
- Snow. Kusatsu has its own small ski area, and the wider region — Manza, Minakami, the Nagano border — makes a winter Kusatsu night a natural pairing with a ski programme.
Access and how it fits a programme
- From Tokyo by rail and bus: limited express from Ueno to Naganohara-Kusatsuguchi (about two and a half hours), then a 25-minute bus up to the town. By highway coach: direct services from Shinjuku and Tokyo Station in around four hours — simpler for luggage and for groups.
- By chartered vehicle Kusatsu is three to three and a half hours from central Tokyo, and the vehicle then makes Ikaho, Tomioka or Karuizawa easy on the way back. Winter tyres and a driver who knows the mountain road are non-negotiable from December to March, and we plan for them.
- Karuizawa, the resort town over the Nagano border, is 90 minutes away by road and on the Hokuriku Shinkansen, which lets a programme run Tokyo → Karuizawa → Kusatsu → Nagano or back to Tokyo without doubling back.
- In a wider itinerary: a one- or two-night Kusatsu stay slots between Tokyo and Nagano — the snow monkeys and Matsumoto are a natural continuation — or replaces Hakone for a client who has done it.
- Timing: Kusatsu is a year-round resort; winter is its signature, autumn colour on the mountain road is superb, and summer is a cool escape from the Tokyo heat. Weekends and Japanese holidays fill the good inns months ahead.
FAQ
How do you get from Tokyo to Kusatsu Onsen? Limited express from Ueno to Naganohara-Kusatsuguchi in about two and a half hours plus a 25-minute bus, or a direct highway coach from Shinjuku or Tokyo Station in around four hours. By chartered vehicle it is three to three and a half hours.
What is the yumomi at Kusatsu? A traditional ritual in which the spring water — too hot and too mineral-rich to dilute — is cooled by stirring with long wooden paddles to song. It is performed several times daily at the Netsunoyu hall beside the Yubatake, and visitors can take part.
Is Kusatsu suitable for groups? Yes. The town has resort hotels that take coaches and groups without difficulty, alongside historic ryokan for smaller high-end parties; the public bath at Sainokawara and the yumomi both accommodate groups.
When is the best time to visit Kusatsu? It is a year-round resort. Winter is its signature season, with snow and steam; autumn brings colour on the mountain approach; summer is cool at 1,200 metres. Book the best inns months ahead for weekends and Japanese holidays.
Want Kusatsu in a programme? Write to b2b@explera.jp, message the trade desk on WhatsApp at +66 93 656 8090, or register on the B2B portal. Proposals within 24 hours. IATA TIDS 96215733, ASTA member 900408341.
