Located in the picturesque town of Kusatsu in Gunma Prefecture's Agatsuma District, Kusatsu Onsen stands as a renowned hot spring resort in Japan's Kanto region.

Known for its abundance of volcanoes and natural hot springs, this destination is widely considered the most famous in Gunma. If you're planning a hot spring itinerary in Japan, this town should be at the top of your list.

Kusatsu Onsen is famous for having the highest natural hot spring water yield in Japan, with an impressive 32,300 liters emerging from the ground every minute — enough to fill 230,000 drums daily. This continuously refreshed water, rich in minerals, gushes naturally from underground sources and is enjoyed undiluted.

The strongly acidic water boasts potent sterilization properties and is believed to be effective for various ailments, including cuts, burns, nerve pain, bruises, diabetes, and high blood pressure. It's often said to “cure everything but heartache.”

Due to its unique qualities, Kusatsu Onsen ranks alongside Arima Onsen in Hyogo Prefecture and Gero Onsen in Gifu Prefecture in Japan’s “Top 3 Hot Springs.”

There are two primary ways to reach Kusatsu Onsen from Tokyo by train.

To save money on transportation, international tourists visiting Japan can purchase the JR TOKYO Wide Pass. The pass costs 10,180 yen for adults (12+) and 5,090 yen for children (6-11). It can be used for unlimited reserved seat rides on limited express trains and bullet trains across the Kanto region for three days. This is a great option if you plan to use the Limited Express Kusatsu or bullet train to get to Kusatsu Onsen.

Moreover, with the pass, you can also easily visit nearby hot spring resort destinations such as Ikaho Onsen.

There are three main highway bus services connecting Tokyo and Kusatsu: The Joshu Yumeguri-go via Tokyo Station and Shinjuku Station; the DTS line via Tokyo Station or Osaki Station and Ikebukuro Station; and the Tokyu Kosoku Bus, which leaves from Shibuya Station. Each takes approximately 5 hours, so feel free to choose your bus depending on which is most convenient.

Drive for roughly an hour from the Nerima Interchange on the Kan-etsu Expressway, and get off at the Shibukawa-Ikaho Interchange. Kusatsu Onsen is another 1.5 hours from there.

Yubatake, literally meaning “hot water field,” is a series of seven wooden slides built in the middle of Kusatsu Onsen to cool the roughly 55°C hot spring water, of which 4,000 liters wells out every minute, while also collecting the sulfur deposits. After the water passes over the slides and is cooled, it is then directed to each hot spring facility. At night, Yubatake is illuminated in an enchanting, mystical display.

To further cool the high-temperature waters of Kusatsu, the “yumomi” technique is used, which sees the water splashed and mixed with 180-centimeter-long paddles. At Netsunoyu, you can watch a yumomi performance synchronized with traditional dance and singing by the “yumomi girls,” whose energy and passion is a joy to watch.

This grand-old footbath recreates the splendor of the public bath “Matsu no Yu,” which stood during the Edo Period. Being right next to the Yubatake, it’s a great place to pause and unwind on your strolls about town. It is free to use, and is open 24 hours, making it the ideal viewing point for the after-dark illumination or as a refreshing way to kick off early mornings.

Sainokawara Park is located in the western part of Kusatsu Onsen, and is dotted by pools of natural hot spring water alongside a geothermal river. The beautiful yet bleak, otherworldly scenery led to its legend as “the place where demons reside,” and it is said that you shouldn’t speak in a loud voice while in the park.

Kusatsu Tropical Wonderland is the highest altitude zoo in Japan, and houses crocodiles, capybara, monkeys, and other subtropical and rare animals. It also boasts the largest collection of reptile species in Japan, and the Jungle Dome, which is warmed by the hot spring heat, remains nice and snug throughout the year, with a climate like Southeast Asia.

Honke Chichiya is the definitive traditional sweets store of Kusatsu Onsen. They have three outlets within the town, including one right in front of the Yubatake, where you can savor freshly-steamed hot spring “manju” buns. Warm and fluffy, they make a tasty accompaniment to your explorations of the town!

Since ancient times, Gunma has produced wheat as an interim crop, and udon noodles are a deeply rooted local dish. For the best udon in Kusatsu, we recommend the “Kuma Bamboo Grass Zaru Udon” served at the day-trip hot spring facility Otakinoyu (650 yen). The batter is mixed with the highly nutritious “kuma” bamboo grass, creating one-of-a-kind green-colored udon! It has a smooth texture that you’ll scoff down in an instant!

Yu no Hana is made from the deposited minerals gathered from the Yubatake, condensing the goodness of the hot springs into a bath salt popular as a souvenir (1,400 yen). Like Kusatsu Onsen’s hot springs, it is highly acidic, and a teaspoon of the powder put into a bucket of warm water makes for a relaxing footbath. Only 7,000-8,000 of these can be made each year, so if you see them, don’t hesitate to pick one up!

The sole pudding store in Kusatsu Onsen, these delectable treats are famous for their photogenic colors, including an emerald green modeled after the Yubatake, and a blue which changes to purple after the accompanying mixture is added, imitating the after-dark light up. The puddings are made with milk from Gunma’s Haruna region, and they boast an irresistibly smooth, melt-in-your-mouth texture.

Grandefiume KUSATSU, a stylish Western-style confectioner around a 6-minute walk from the Yubatake, is popular for its “Kusatsu Rusk.” Crafted from a blend of different flours, it has a crispy bite coming in plenty of flavors, including Earl Grey, maple, caramel, and almonds. The Kusatsu Rusk set is 510 yen (8 pack), while other sets like caramel and almonds is 560 yen (8 pack), and the “Kusatsu Rusk Sugar,” made with fragrant roasted butter and sugar in bite-sized pieces, is 560 yen, among others.

Each of the following hotels and ryokans is rated 8+ out of 10 on Booking.com.

While many consider autumn and winter to be the best times for hot springs, Kusatsu Onsen offers enough charm to draw in visitors throughout the year. Being at an altitude of 1,200 meters, the average temperature in summer is 18°C, making it a popular getaway from the unbearable humidity of Japan. Refreshing breezes often blow across Sainokawara Park, making it heaven for summertime strolls.

Events are also held in Kusatsu Onsen regularly, and the most lively of these is the Kusatsu Onsen Appreciation Festival in August, where locals parade dressed up as goddesses to give thanks to the hot springs and for a year of sound health.

Surrounded by mountains, skiers and snowboarders visiting in winter can get their thrills at ski resorts like Kusatsu Onsen Ski Resort and Manza Onsen Ski Resort.

Kusatsu Onsen, one of Japan’s Top Three Hot Springs boasting the most natural hot spring water in Japan, can be easily accessed from Tokyo by bus and train. Next time you’re seeking out a hot spring oasis in Japan to unwind and heal, make sure Kusatsu Onsen is on your list!

*This article was originally published in January 2023. Please check official websites for the latest information.