Kusatsu Onsen — Yumomi Ceremony and the Unique Acidic Famous Hot Spring

Kusatsu Onsen in Kusatsu Town, Agatsuma District, Gunma Prefecture, is one of Japan's three most celebrated hot springs, boasting the nation's greatest natural discharge of thermal water. Characterized by strongly acidic water (a pH of around 2), it is a historic spa town praised as being able to "cure anything but lovesickness." The sight of steam rising over the highland at about 1,200 meters is quintessentially Japanese. Some one hundred springs well up throughout the town, and this sheer volume speaks to the power of these waters.

Highlights

• Yubatake: The symbol of Kusatsu at the center of the spa town. Thousands of liters of source water gush out each minute, and the wooden channels where the mineral "yu-no-hana" is harvested are a striking sight. The nighttime illumination is enchanting
• Public baths (jikan-yu and bath-hopping): Shirahata-no-Yu, Chiyo-no-Yu, Jizo-no-Yu, and other public baths, free or inexpensive, are dotted about. Kusatsu is also known for the tradition of "jikan-yu," a formal bathing practice
• Sainokawara Park: An unusual park where the river itself flows as hot spring water, with a vast open-air bath within the grounds
• Spa-town stroll: Souvenir shops selling hot-spring manju and yu-no-hana, and eateries, gather around the Yubatake, making a wander a pleasure

Enjoying the Seasons

A snow-viewing bath in winter (December to March) is the most atmospheric; the snow-dressed Yubatake is exceptional. Summer (July to August) is popular as a cool retreat thanks to the high elevation, pairing an escape from the heat with the hot springs. The fresh green of spring and the foliage of autumn are also beautiful, wrapping the Yubatake area in seasonal color. Owing to the highland climate, mornings and evenings stay cool even in summer, so the springs can be savored at leisure year-round.

Access & Basic Information

• Location: Kusatsu, Kusatsu Town, Agatsuma District, Gunma Prefecture
• By train: About 25 minutes by bus from Nagano-hara-Kusatsu-guchi Station on the JR Agatsuma Line
• Highway bus: Direct highway buses run from the Tokyo area, reachable without transfers
• Public baths: Many are free (they are part of local residents' daily life; mind your manners)
• Elevation: About 1,200 meters; cool even in summer thanks to the highland setting

Practical Travel Notes

Kusatsu's water is very strongly acidic with high antibacterial power, but it can be harsh for those with sensitive skin. Start with short soaks, and if you notice irritation afterward, rinsing with fresh water is reassuring. Metal accessories can discolor, so remove them before bathing. Public baths are also part of local residents' daily life, so keep your voice down and follow basic etiquette such as rinsing yourself before entering. Inns fill up quickly on weekends, holidays, and the New Year period, so booking accommodation early is wise.

A Word of Advice

The appeal of Kusatsu Onsen is that the spa town spreads around the Yubatake and can be comfortably explored on foot. Once you have dropped your bags at the inn, head first to the Yubatake, enjoying the steam and mineral flowers by day and the enchanting illuminated scene by night. After a good soak in the strongly acidic water, go bath-hopping among the public baths and snack on hot-spring manju as you stroll. Savoring this famous spring, with the nation's greatest discharge, through all five senses is the tabitabi JAPAN editorial team's recommended way to spend time in Kusatsu.

📚 Sources

The content here is organized from public information by the Kusatsu Onsen Tourism Association, official tourism information from Kusatsu Town, public information from the bodies managing the Yubatake and public baths, and on-site guidance. The hours of the public baths, the yumomi-related events, and the operation of highway buses change by season. Lodging fills early on weekends, holidays, and the year-end and New Year. Because fees, hours, and access can change, please confirm with official sources before you set out.

Visitor Checklist

• Time needed: A half day for a town stroll and viewing the Yubatake, or a half day to a full day with a bath-hopping circuit and nearby walks.
• What to bring: There are many stone-paved streets and slopes, so wear comfortable shoes. Kusatsu's water is very strongly acidic with high disinfecting power but can be harsh on sensitive skin, and metal accessories may discolor, so remove them before bathing.
• Suggested route: Stroll the hot-spring town around the Yubatake and enjoy Sainokawara Park and a bath-hopping circuit.
• Bathing manners: Public baths are part of local daily life, so pour water over yourself before entering and refrain from loud voices, keeping basic manners.
• Combining nearby: The night illumination around the Yubatake is also a highlight, so an after-dinner stroll is recommended.

Practical Information for Your Visit

Here is information on the main day-use bathing facilities and the parking lots at Kusatsu Onsen.

• Opening hours: The Sainokawara Open-Air Bath is open 7:00-20:00 from April 1 to November 30 and 9:00-20:00 from December 1 to March 31 (last entry 19:30 in both seasons)
• Prices: The Sainokawara Open-Air Bath costs 800 yen for adults and 400 yen for children. The Yumomi and Dance Show at Netsunoyu costs 700 yen for adults and 350 yen for elementary school children (tax included)
• Parking: For the Sainokawara Open-Air Bath, use Tengu-yama Parking Lot No. 1 (free of charge, 300 spaces). The Yubatake Tourist Parking Lot has 180 spaces and costs 700 yen for an ordinary car and 300 yen for a motorcycle (both for stays of less than 2 hours)
• Telephone: Sainokawara Open-Air Bath, 0279-88-6167
• Address: 521-3 Oaza Kusatsu, Kusatsu-machi, Agatsuma-gun, Gunma Prefecture 377-1711 (Sainokawara Open-Air Bath)

Note: The regular closing days of the Sainokawara Open-Air Bath are not published on its official website (temporary changes to opening hours are sometimes announced). Note: The times of the shows at Netsunoyu vary from day to day, so please check the same-day information on the official website.

(Sources: official website of the Kusatsu Onsen Tourism Association; official Kusatsu Santo website of the Kusatsu Tourism Public Corporation; official Kusatsu Town website)