Gunma Prefecture sits on Japan’s volcanic spine and produces more hot spring water than any other prefecture — earning it the unofficial title of Japan’s onsen capital. The three great resort towns of Kusatsu, Ikaho, and Minakami each have a distinct personality, and all three are within 2.5 hours of Tokyo.

Best Areas to Stay

Kusatsu Onsen — Japan’s Finest Sulfuric Spring

Japan’s most celebrated hot spring town, located at 1,200 m elevation in the mountains of northern Gunma. The Yubatake (hot water field) at the town centre produces 32,000 litres of water per minute. Best for: onsen purists, couples, winter snow onsen.

Ikaho Onsen — Retro Atmospherics

A hot spring resort built on a hillside above the Tone River, connected by a famous 365-step stone staircase flanked by inns and souvenir shops. Two spring types: brown iron-rich water and clear silica water. Best for: nostalgia tourism, affordable ryokan, autumn foliage.

Minakami — Adventure & Onsen Hybrid

A river canyon resort town on the upper Tone River with white-water rafting, canyoning, bungee jumping, and several excellent onsen facilities. Tanigawadake mountain skiing in winter. Best for: active travellers wanting adventure sports plus ryokan.

Shima Onsen

A remote, little-visited hot spring village deep in the mountains. Inspired Hayao Miyazaki’s Spirited Away bathhouse according to popular belief (as did several others). Genuinely quiet and atmospheric. Best for: Ghibli pilgrims, travellers seeking Japan without tourists.

Kusatsu Onsen Ryokan

Nishiyama Onsen Keiunkan (UNESCO World Heritage Candidate)

Actually in adjacent Shizuoka but Japan’s equivalent: in Kusatsu, the comparable historic establishment is Kusatsu Onsen Hotel Ichii — a multi-generational ryokan at the centre of the town with direct access to the communal yumomi (water stirring) ceremony baths.

Ryokan Yamashiro ⭐⭐⭐⭐

A mid-size ryokan in Kusatsu town centre — sulfuric spring water at 46°C, multi-course Gunma mountain kaiseki, and a top-floor rotenburo overlooking the forested mountains. ¥22,000–¥40,000/pp.

Komaki Onsen Hotel

The most affordable reliable ryokan option in Kusatsu — clean, well-maintained, with access to multiple indoor and outdoor baths. ¥14,000–¥20,000/pp. Good for budget-conscious couples.

Ikaho Onsen Ryokan

Fukuiya Ryokan ⭐⭐⭐⭐⭐

The premier ryokan in Ikaho — views over the Tone River valley from private room balconies, exceptional kaiseki using local Gunma produce (konyaku, river fish, mountain vegetables), and both the brown and clear spring water baths on-site. ¥35,000–¥65,000/pp.

Kazurabei (Mid-Range)

A well-regarded ryokan on the famous stone-step arcade — rooms facing the steps are characterful though noisy during the day. The brown iron spring water bath is available. ¥18,000–¥28,000/pp.

Minakami Accommodation

Takaragawa Onsen Osenkaku ⭐⭐⭐⭐⭐ (Mixed Gender)

One of Japan’s most famous outdoor baths — four massive open-air pools on the banks of the Takara River, surrounded by river forest and snow in winter. One of the few major onsen in Japan with mixed-gender (konyoku) outdoor baths. Stay or day-use ¥1,800. Overnight ¥22,000–¥38,000/pp.

Hotel Fujin, Minakami

A modern resort hotel with rafting and outdoor activity packages built in. River-facing rooms, natural onsen bath, and guided adventure activity coordination. ¥15,000–¥28,000/night.

Practical Tips

  • Kusatsu acidity: The spring water at 2.1 pH is among Japan’s most acidic — it kills bacteria and soothes skin, but prolonged immersion irritates sensitive skin. Limit each bath to 3 minutes. The town has a free communal footbath on the Yubatake plaza.
  • Ikaho access: From Shibukawa Station (Joetsu Shinkansen), take a direct bus to Ikaho (25 min). The stone steps are always open — arrive in the evening after tourists leave for the most atmospheric experience.
  • Minakami rafting season: April to October. Spring snowmelt (April–May) provides the most intense rapids — Grade 4 sections suitable for fit adults with no prior experience.
  • Shima Onsen: Accessible by bus from Nakanoio Station. Very limited accommodation — book well ahead. Cell signal is poor.
  • Winter onsen: Kusatsu in January-February with snow on the roof tiles and steam from the Yubatake rising into cold mountain air is one of Japan’s great winter experiences.