Private, Mixed-Gender, and Bathing Suit-Optional: Hot Spring Experiences in Gunma for Everyone

Hotels and inns around Gunma often have their own hot springs, and many have rooms with en suite, hot-spring-fed baths for a private dip whenever you want.

The town of Kusatsu is renowned for its iconic Yubatake geothermal spring in the middle of the town, which is the source of the area’s steaming-hot, mineral-rich water. Just a short walk away, Yubatake Sensui offers modern rooms with a stylized, traditional Japanese aesthetic. Each one has a ceramic bath fed with water from the Yubatake. Atop a hill overlooking the town, Tokinoniwa is a traditional inn with modern facilities where every room features its own open-air bath looking out onto peaceful natural surroundings.

For those seeking an escape into nature, the Minakami area offers several luxurious options. Aratashi Minakami is a modern hotel in Minakami Onsen where every room comes with a bath on the balcony, facing out over the Tone River. Slightly further downstream, Tatsumikan has rooms that come with their very own saunas and cold baths in addition to a private onsen. For skiers, Minakami Kogen Hotel 200 offers a similar experience but much higher in the mountains, perfect for relaxing after a day of hitting the slopes.

Travelers in search of internationally acclaimed extravagance may want to consider Bettei Senjuan, a RELAIS & CHÂTEAUX-registered and Michelin Key-awarded retreat in the mountains of Minakami where each room is a work of Zen-inspired art, featuring baths with striking views of Mt. Tanigawa. Kaichoro in Ikaho Onsen offers an intimate experience—with only eight rooms, the hotel provides highly attentive service. Some of the rooms feature private gardens with outdoor baths for leisurely, carefree soaks. Guests can also enjoy gourmet seasonal meals and relaxing spa treatments during their stay.

Beyond the public bath, some facilities have private onsen that can be reserved for exclusive use at a designated time. This is a popular choice for couples and families, as it allows them to enjoy a shared, yet private, bathing experience.

Shima Onsen is a quiet, secluded town deep in the Gunma countryside known for its traditional accommodations. Shima Onsen Kashiwaya Ryokan is one such inn that retains an old-fashioned charm. It has three open-air baths that can be booked for exclusive use, 30 minutes at a time. History enthusiasts may appreciate Shima Tamura, an inn established almost 500 years ago. Its reservable indoor bath is perfect for families and comes with the use of a rest area afterward. At Shima Grand Hotel, guests can book modern baths crafted by a leading interior designer, offering picturesque views of lush greenery and a mountain stream.

In Kusatsu, Konoha has three free, differently themed, private baths available exclusively for staying guests. Conversely, day-trippers have several excellent options: Kusatsu Now Resort Hotel, Naraya, and Kusatsu Onsen Gensen Ichinoyu all offer private baths that can be reserved for a fee by non-staying guests.

In the historic hillside onsen town of Ikaho many accomodations have baths that draw from Ikaho’s mineral-rich waters, notably its Kogane-no-Yu "golden waters," so called because their iron content oxidizes to a unique, reddish-brown or amber color when exposed to air. These include Chigira Jinsentei, a long-established inn with private baths that do not require booking, and Moriaki Ryokan, which offers reservable private baths. The two private baths in Oyado Tamaki are uniquely designed to resemble caves, complete with dramatic rock features.

In Minakami, guests at the luxury boutique hotel, Kanzan Super Hydrogen Rich Spa, can use either of two private 24-hour baths that are available free of charge, without reservation, on a first-come, first-serve basis. Sarugakyo Hotel has four private baths—two indoor and two open-air. Ryokan Tanigawa also provides a reservable open-air bath with views of the surrounding mountains.

While some places allow staying guests to charter baths for free, others may charge per session. Most rentals include free use of a rest area. Booking policies vary; some require reservations, others allow bookings at check-in or on arrival, and some don't require bookings at all and can be used by guests as long as they are available.

Mixed-gender bathing, known as konyoku, is less common today but still offers a unique, traditional onsen experience in Gunma.

Takaragawa Onsen Osenkaku in Minakami is famous for its large mixed-gender, open-air onsen positioned right along the Takara River. To ensure modesty, the hotel provides guests with special bathing suits for use in the konyoku areas. Be aware that guests are not permitted to bring or use their own swimwear.

At Sainokawara Open-Air Bath, a 500-square-meter open-air bath in Kusatsu, the men’s bathing area is open to everyone on Friday evenings (while the women’s bath continues to operate as a regular, gender-segregated facility). During these hours, guests may bathe together without the typical gender segregation while wearing bathing suits. Women may wear their own swimsuits or rent a bathing suit, while bathing suits for men are provided free of charge. Please note that minerals in the hot spring waters may cause discoloration to any fabrics.

The historic Hoshi Onsen Chojukan, located in Joshin'etsukogen National Park, feels like a retreat from a different era and is designated a National Tangible Cultural Property. This location maintains a traditional policy: no clothes are allowed in the mixed-gender baths, including towels. For guests who don’t want to use the konyoku baths, the establishment also has segregated baths.

Open-air baths (rotenburo) are a great way to connect with nature and the changing seasons, and many hotels in Gunma feature onsen with a scenic view of the surrounding landscape.

Manza Prince Hotel, located in front of the slopes of Manza Onsen Ski Resort, is renowned for its open-air onsen set high on the mountainside. By day, guests can enjoy uninterrupted views of the neighboring peaks, and on a clear night, the low light pollution means you can take a hot bath under a starry sky.

Kawaba Onsen Yutorian in the Gunma countryside is steeped in traditional bucolic charm. The hotel’s buildings feature thatched roofs and tatami-mat floors, and its tranquil open-air baths overlook a quaint Japanese garden.

Footbaths (ashiyu) are an easy and quick way to experience onsen, as you need only remove your shoes and socks. Maybe roll up your pants and hike up your skirt as well. Kishigon Ryokan, located halfway up the Ikaho Stone Steps, is perfect for a quick break and offers a small roofed footbath in front of their grounds, freely available to everyone. In Kusatsu, the acidic waters flowing into the free Yukemuri-tei footbath, right next to the Yubatake, are widely thought to have therapeutic properties.

Another casual way to partake in onsen culture is by drinking the mineral-rich water at designated drinking spots, which is believed to offer different health benefits depending on the waters’ composition. In Ikaho, you can find the Ikaho Onsen Drinking Fountain tucked away near the Kajika Bridge. In Shima Onsen, the Shio no Yu and Yuzuriha fountains are two places where you can try the hot spring water. Before you drink, always make sure to check the recommended maximum consumption amount usually indicated by signage. Some signs are only available in Japanese, and might require the usage of a smartphone and translation app.

There are several onsen that cater to a family’s needs, providing baby-friendly equipment with an emphasis on convenience and comfort for all.

Toshimaya in Shima Onsen takes great care and attentiveness to guests with babies, offering stays with special amenities and services. Packages include rooms with en suite onsen baths and in-room dining.

Nakaya Ryokan in Minakami is another inn taking extra steps to welcome families with young ones. The inn comes with a kids’ playroom and baby-friendly indoor and outdoor baths complete with baby toys. Guests can also rent a private onsen, equipped with the necessary infant essentials.

Hotel Matsumotoro in Ikaho features two private indoor baths with onsen waters that are very gentle, making them suitable for a baby’s sensitive skin. Each bath is available for rent and comes with baby equipment. The hotel also provides yukata and futons for young children.

When planning an onsen trip to Gunma, consider what kind of bathing experience you want. Rooms with a private en suite onsen are often very popular and need reserving well in advance. Similarly, private-use baths may require booking at the time of reservation or upon check-in, so checking the facility's policy beforehand is highly recommended. If you plan to visit mixed-gender baths, be sure to check the policy regarding bathing suits. For day-trip bathing, do some research in advance or ask for assistance at the nearest tourist information center, as not all accommodations make their hot springs available to non-staying guests, and prices, availability, and policies will vary. Lastly, take time to review general bathing etiquette, and if you have a tattoo, make sure to check with each facility because many have restrictions and differing policies.