パソコパソコだよ！今日も一緒に学んでいこう！
Kusatsu Onsen is one of Japan’s “Three Great Hot Springs” (日本三大名湯), producing over 32,300 litres of water per minute—the highest natural flow of any hot spring in Japan. Located in Gunma Prefecture, about 3 hours by highway bus from Tokyo, it’s one of the most accessible premium onsen destinations in the country.
This guide is based on an actual 2-day trip in September 2023.
Day 1 trip report → Kusatsu Onsen Day 1: Yubatake, Hot Spring Town & Ryokan Dinner (English)
Day 2 trip report → Kusatsu Onsen Day 2: Otaki-no-Yu, Gunma Beef BBQ & Temple Visit (English)
Basic Data
| Item | Details |
|---|---|
| Location | Kusatsu-machi, Agatsuma-gun, Gunma Prefecture |
| Distance from Tokyo | ~3–3.5 hrs by highway bus / ~3 hrs by car |
| Spring type | Acidic sulfur-aluminium sulfate-chloride spring (pH 2.1) |
| Output | 32,300 litres/minute (highest in Japan) |
| Main attractions | Yubatake, Otaki-no-Yu, Goza-no-Yu, Kosen-ji Temple, Mt. Shirane |
| Best season | Year-round (snow-view onsen in winter is popular) |
| Typical trip | 1 night, 2 days (day trip is also possible) |
Getting There
By Highway Bus from Tokyo (Recommended)
| |
Fare: One-way approx. ¥2,700–3,300
Booking: Reserved seating required. Book via Kan-etsu Kotsu or JR Bus Kanto websites
Note: Weekends and holidays sell out 2–3 weeks in advance. Book as early as possible.
By Shinkansen + Local Bus
| |
By Car
| |
Main Attractions
Yubatake (湯畑)
The symbol of Kusatsu Onsen. A large, open-air spring source where 32,300 litres per minute flow through wooden channels designed to cool the water before it enters the baths. The scale and the sight of actual hot spring water flowing in open air are unlike anything elsewhere in Japan.
Daytime: The steam and flowing water are dramatic in natural light
Night: The area is beautifully lit—blue-tinged lights create an ethereal atmosphere completely different from the daytime look
Entry: Free, open 24 hours
Otaki-no-Yu (大滝乃湯)
The most famous public bath facility in Kusatsu Onsen, known for its “awase-yu” system—a series of baths at incrementally higher temperatures, following the traditional practice of gradually conditioning the body to Kusatsu’s intense acidity.
| Item | Details |
|---|---|
| Hours | 9:00–21:00 (last entry 20:00) |
| Entry fee | Adult ¥800 |
| Spring type | Acidic sulfur spring (pH 2.1) |
| Features | Awase-yu (5-temperature progression), outdoor bath |
Tip: Even if your ryokan has excellent baths, the awase-yu at Otaki-no-Yu is a distinctly Kusatsu experience worth doing separately.
Goza-no-Yu (御座之湯)
A day-use bath right next to the Yubatake. Wooden architecture that evokes the historical atmosphere of the old hot-spring town.
| Item | Details |
|---|---|
| Hours | 7:00–21:00 (last entry 20:00) |
| Entry fee | Adult ¥700 |
| Location | 1-min walk from Yubatake |
Kosen-ji Temple (光泉寺)
A Tendai Buddhist temple regarded as the guardian temple of Kusatsu Onsen. Located in the centre of the hot spring town, its stone steps lead up to a main hall that looks down over the Yubatake. A quiet, reflective contrast to the busy onsen town below.
2-Day Model Itinerary
Day 1
| Time | Place | Notes |
|---|---|---|
| 13:00 | Arrive at Kusatsu Onsen | By highway bus |
| 13:30 | Yubatake | See it in daylight first |
| 14:00 | Hot spring town walk | Old-style coffee shops, local shops |
| 15:00 | Lunch (maitake mushroom tempura, etc.) | Local Gunma speciality |
| 16:00 | Natural walk around the river | Volcanic riverscape near Mt. Shirane |
| 17:00 | Ryokan check-in | Change into yukata, first bath |
| 18:30 | Ryokan dinner (kaiseki) | Joshu pork, onsen egg dishes, local ingredients |
| 20:00 | Yubatake night illumination | Blue lights + steam = otherworldly |
| 21:00 | Night walk through the onsen town | Goza-no-Yu and Kosen-ji lit up at night |
| 23:00 | Sleep | Take one more bath before bed |
Day 2
| Time | Place | Notes |
|---|---|---|
| 07:00 | Morning bath | Ryokan hot spring before breakfast |
| 08:30 | Ryokan breakfast | |
| 10:00 | Otaki-no-Yu | Awase-yu experience (1–2 hours) |
| 12:00 | Lunch (Gunma beef BBQ, etc.) | Charcoal-grilled local beef |
| 13:30 | Kosen-ji Temple visit | Quiet stone steps, views over the Yubatake |
| 14:30 | Souvenirs | Onsen manju, yuno-hana (sulfur crystals), etc. |
| 16:00 | Highway bus back to Shinjuku | |
| 19:00 | Arrive Shinjuku |
Cost Breakdown (Per Person, 1 Night)
| Item | Estimated cost |
|---|---|
| Highway bus (Shinjuku round trip) | Approx. ¥5,400–6,600 |
| Accommodation (2 meals included) | ¥15,000–40,000 (varies by grade) |
| Otaki-no-Yu entry | ¥800 |
| Goza-no-Yu (optional) | ¥700 |
| Lunch and snacks | ¥2,000–4,000 |
| Souvenirs | ¥1,000–3,000 |
| Total (estimate) | ¥25,000–55,000 |
Budget-by-Style Guide
| Budget | Style |
|---|---|
| ¥20,000–30,000 | Simple inn with breakfast only; prioritise spending on food |
| ¥30,000–50,000 | Standard onsen ryokan with 2 meals |
| ¥50,000+ | High-end ryokan with private open-air bath; special occasions |
Local Food Worth Trying
- Maitake mushroom tempura: Gunma-grown giant maitake mushrooms, battered and fried. Crispy and deeply flavoured—available at izakaya and restaurants in the onsen town
- Joshu pork dishes: Gunma’s branded pork appears on most ryokan menus
- Gunma beef BBQ: Charcoal-grilled local beef—outstanding quality after a morning at the hot springs
- Onsen manju: The signature souvenir of Kusatsu. Freshly steamed ones are best
- Onsen tamago (hot spring eggs): Slow-cooked eggs in the hot spring water. Ryokan dinners often feature these
Seasonal Guide
| Season | Highlights | Watch for |
|---|---|---|
| Spring (Apr–Jun) | Fresh green, snowmelt | Can still be cold until late April |
| Summer (Jul–Aug) | Cool highland air, fireworks | Peak crowds |
| Autumn (Sep–Nov) | Autumn foliage, Mt. Shirane colour | Most beautiful foliage in Oct–Nov |
| Winter (Dec–Mar) | Snow-view onsen, skiing nearby | Road icing; check access before you go |
Off-peak tip: January–February weekdays. Cold, yes—but almost no crowds, lower accommodation rates, and the chance to have an outdoor bath almost to yourself in the snow.
Common Mistakes and How to Avoid Them
Mistake 1: Couldn’t get a bus ticket
→ Weekend and holiday buses sell out 2–3 weeks in advance. Book immediately once your dates are fixed.
Mistake 2: Ryokan was fully booked
→ Popular ryokan fill up a month before weekends. Book early, especially for Golden Week, Obon (mid-August), and New Year.
Mistake 3: Skin irritation from the spring
→ At pH 2.1, Kusatsu is strongly acidic. Avoid extended soaks, and rinse thoroughly after bathing. Those with sensitive skin should take it easy.
Mistake 4: Mt. Shirane was closed
→ Volcanic activity regulations change. If you plan to hike near Mt. Shirane, check current access restrictions before departing.
Summary
Kusatsu Onsen delivers on every dimension: the highest-output hot spring in Japan, a spring type with genuine health properties (the acidity is cited in historical records as therapeutic), dramatic scenery at the Yubatake, excellent local food, and warm ryokan hospitality. If you’re planning a first Japanese onsen trip—or trying to choose between options—Kusatsu is rarely a wrong answer.
Related Articles
- Kusatsu Onsen Day 1: Yubatake, Hot Spring Town & Ryokan Dinner (English)
- Kusatsu Onsen Day 2: Otaki-no-Yu, Gunma Beef BBQ & Temple Visit (English)
- 草津温泉完全ガイド（日本語）
- Hakone 2-Day Guide: Old Road Hike, Lake Ashi & Onsen (English)
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