Manza Onsen: High-Altitude Hot Springs & Skiing in Gunma

Why Manza Onsen: Hot Springs at 1,800 Meters

Manza Onsen (万座温泉) sits at 1,800 meters (5,900 feet) on the slopes of Mt. Kusatsu-Shirane in Gunma Prefecture. That elevation makes it one of the highest hot spring areas in Japan that remains accessible by road year-round — a fact that shapes everything about the place, from its milky sulfurous water to its reliable winter snowfall.

Unlike the bustling streets of Kusatsu town just over the mountain, Manza is quiet and remote. There are no shopping arcades, no rows of souvenir stores. What you get instead is a handful of ryokans and hotels clustered on a mountainside, volcanic steam rising through the trees, and some of the most mineral-rich water in the country. For travelers exploring Gunma's onsen town destinations, Manza offers a rawer, more isolated alternative to the region's better-known hot springs — including the riverside baths at Takaragawa Onsen.

The settlement itself is small. Most visitors come for one or two nights, splitting their time between the baths and — in winter — the adjacent ski slopes. There is no town center to explore. The experience is the water, the mountain air, and the views from the rotenburo (outdoor baths) when snow blankets everything around you.

The Water: Sulfurous Springs from Mt. Kusatsu-Shirane

Manza's water is sourced from the volcanic activity of Mt. Kusatsu-Shirane (草津白根山), an active volcano rising to 2,160 meters. The springs produce highly acidic, sulfurous water that emerges milky and opaque with a strong sulfur smell — the kind of water that stains towels and lingers on your skin for hours.

According to NAVITIME Japan Travel, the area's daily hot water discharge is 5.4 million liters. That volume, combined with the high sulfur content, has given Manza a long-standing reputation for therapeutic bathing. The water is traditionally associated with benefits for skin conditions and blood circulation, though individual results vary.

The bathing experience here feels different from lower-altitude onsen towns. At 1,800 meters, the air temperature is noticeably cooler — even in summer — which makes the contrast between the hot water and the surrounding air more dramatic. In winter, soaking in an outdoor bath while snow falls around you is the defining Manza experience. Several ryokans offer rotenburo with mountain views, and the area's remoteness means minimal light pollution for clear stargazing from the baths.

One practical note: the high sulfur content means you should not wear jewelry into the water. Metal tarnishes quickly in these springs.

Manza Onsen Ski Resort: Skiing into the Hot Springs

Manza Onsen Ski Resort (万座温泉スキー場) is located directly adjacent to the onsen hotels, making it one of the few places in Japan where you can genuinely ski in the morning and soak in sulfur springs by afternoon — without driving anywhere.

Trail and Lift Overview

The resort is compact: 9 trails served by 4 lifts, spanning elevations from 1,648 meters to 1,994 meters (5,407 to 6,542 feet). According to Powderhounds, the layout is easy to navigate without a mountain host, and the terrain suits intermediate skiers and snowboarders well. This is not a destination for those seeking steep chutes or extensive backcountry — it is a resort built around the onsen-and-ski combination.

Lift ticket prices were not verifiable from official sources at the time of writing. Check the resort's official site for current rates, and look for early bird discount options that are typically available through online booking.

Snow Conditions and Season

The high elevation is the key advantage. At nearly 2,000 meters at the summit, Manza receives reliable natural snowfall and maintains good snow quality through the winter season. According to Powderhounds, the south-facing slopes can soften in spring sunshine, so midwinter — December through February — offers the best conditions.

The ski season typically runs from late November or early December through late March, though exact dates depend on snowfall each year.

Where to Stay: Nisshinkan and Other Accommodation

Nisshinkan (日進館) is the most well-known accommodation in Manza Onsen. The large ryokan-style hotel sits at the heart of the onsen area and offers multiple indoor and outdoor baths filled with the area's sulfurous water. It is the default choice for most visitors and the property you will encounter most frequently in Japanese travel guides.

According to Japan Travel, onsen access in Manza requires staying at a hotel or ryokan — there are no dedicated public day-trip bathing facilities. This means your accommodation choice directly determines your bathing experience.

Prince Hotels also operates properties in the Manza area. According to the Prince Hotels official site, their guests may have access to dedicated shuttle bus service from Karuizawa Station, which simplifies the access logistics considerably.

Rates for Nisshinkan and other properties fluctuate seasonally, with winter (ski season) commanding higher prices. Current rates were not verifiable from official sources — book directly through the property websites or Japanese booking platforms for the most accurate pricing.

Getting to Manza Onsen from Tokyo and Kusatsu

Manza's remote mountain location means travel time is significant regardless of your approach. Plan for at least three hours from central Tokyo.

By Shinkansen and Bus via Karuizawa

The standard public transport route is the Hokuriku Shinkansen from Tokyo Station to Karuizawa Station — approximately one hour. From Karuizawa, a highway bus runs to the Manza area, taking roughly two hours along mountain roads. According to Visit Gunma, the total journey from Tokyo is approximately three hours.

An alternative rail approach uses Manza-Kazawaguchi Station on the JR Agatsuma Line, but the bus connection from there to Manza Onsen takes approximately one hour and 45 minutes, making the Karuizawa route generally more practical.

If you are staying at a Prince Hotels property, check whether dedicated shuttle bus service from Karuizawa Station is available — this can simplify the final leg significantly.

The Kusatsu-Manza Road Connection

In summer, you can drive between Kusatsu Onsen and Manza in approximately 30 minutes. This makes it easy to combine both onsen towns in a single trip — the contrast between Kusatsu's lively town atmosphere and Manza's alpine solitude is worth experiencing.

However, this road closes in winter due to heavy snow on Mt. Kusatsu-Shirane. During winter months, the only road access to Manza is from the south via the Manza Highway (万座ハイウェー), which connects to the Karuizawa area. This is a critical detail for winter trip planning — you cannot simply drive over from Kusatsu when the snow sets in.

Route	Transport	Time	Notes
Tokyo → Karuizawa → Manza	Shinkansen + bus	~3 hours	Most common public transport route
Karuizawa → Manza	Highway bus	~2 hours	Mountain roads, scenic but winding
Kusatsu → Manza	Car (summer only)	~30 minutes	Road closed in winter
Manza-Kazawaguchi Stn → Manza	Bus	~1 hour 45 min	Less frequent service
Tokyo → Manza	Car via Manza Highway	~2.5-3 hours	Year-round access from south

When to Visit: Winter Skiing vs Summer Hiking

Manza offers two distinct experiences depending on the season.

Winter (December–March) is peak season. The combination of skiing and onsen bathing is the main draw, and the snow-covered rotenburo experience is what most visitors come for. Expect higher accommodation prices and the need to book in advance, especially around New Year and February holidays. Access is limited to the Manza Highway from the south — no Kusatsu connection.

Summer (June–September) brings a cooler mountain retreat. While the rest of Gunma swelters in humidity, Manza's 1,800-meter elevation keeps temperatures comfortable. Hiking trails open along mountain streams, and Kumashiro Cave becomes accessible — a feature that is off-limits in winter. The road to Kusatsu opens, enabling easy day trips between the two onsen areas. Summer is quieter and cheaper, though you lose the dramatic snow-and-steam atmosphere.

Spring and autumn are transitional. Some facilities may have reduced hours, and weather at altitude can be unpredictable. These shoulder seasons can offer good value if you are flexible with plans.