Kusatsu Onsen is one of the most famous hot spring resorts of Japan. It is located at an altitude of 1,200 metres above sea level in the mountains of Gunma Prefecture, about three to four hours by bus from Tokyo. Kusatsu Onsen is known for its high quality hot spring water that is thought to warm the body and help kill bacteria. Much of the resort’s water bubbles up in the yubatake (“hot water field”) in the town centre, where visitors can see the large amounts of steam rising. In addition to Yubatake, there are other spring sources such as Shirahata, Bandaiko, Sainokawara, Nigawa, and Jizo. The spring quality differs depending on its source, therefore, it is recommended to visit several of them in order to experience the different water.
In addition to the hot spring experience, more
Kusatsu offers the possibility of skiing in winter and hiking during the rest of the year. 

Manza Onsen is a hot spring resort town located at an altitude of 1,800 metres above sea level, high up on the slopes of Mount Shirane at the northwestern edge of Gunma Prefecture. Its waters obtained from Mount Shirane are among the most sulphuric waters in Japan and offer different health benefits including improving metabolism and blood circulation.

The hot spring town is enjoyable year-round: in winter, it is a great place for enjoying an open-air bath in the snow, while in summer, it offers you the possibility to cool down with the brisk temperatures in the high mountains. Manza Onsen also offers skiing and snowboarding from around mid-December to early April and is the site of Manza’s yubatake (“hot water field”), a pool in which some of the thermal waters accumulate. more
However, the yubatake is too hot for bathing. Manza Onsen has several hotels and ryokan with outstanding hot spring baths both for staying guests and daytime visitors. Hiking lovers can enjoy the small network of pleasant walking trails around the valley that contains many of the hot spring sources.
Located about one hour away from Tokyo near Mount Fuji, Hakone Onsen in Kanagawa Prefecture has been one of Japan’s most popular hot spring resorts for centuries. Its beautiful setting along the forested valley and the shores of Lake Ashinoko makes Hakone Onsen very popular and very enjoyable. More than a dozen springs provide hot spring water to the many bathhouses and ryokan in Hakone region. Many ryokan open their baths both to staying guests who can use the baths for free and to daytime visitors who must pay an admission fee. Most onsens are not private, which means that there might be other customers and you will have to bath naked in most onsens.
One of the hot springs where you can wear your bathing suit is Yunessun. This hot spring theme park offers you a unique way to experience the hot springs of Hakone. more
It has some non-traditional baths, like a wine bath, a coffee bath (the first of its kind in Japan), a green tea bath or a Japanese sake bathFurthermore, you can also enjoy the private baths, the outdoor baths with beautiful scenery, the warmed stone room, the Finnish sauna and the aroma room. 
Minakami Onsen is a hot spring resort town in Gunma Prefecture, located about one hour away from Tokyo. There are over a dozen separate hot spring sources found across the mountains and valleys of Minakami, which favoured the development of different hot spring resorts including Takaragawa Onsen, Hoshi Onsen, Sarugakyo Onsen, Tanigawa Onsen and Yubiso. Some resorts consist of numerous big hotel complexes, while others, such as Takaragawa Onsen and Hoshi Onsen (traditional wooden indoor baths) are remote, rustic ryokans isolated deep in the mountains. Takaragawa Onsen is known for its large riverside rotenburo (open-air baths), most of which are for mixed-gender bathing, with one women-only bath. Osenkaku ryokan of Takaragawa Onsen has some of the largest rotenburo (outdoor baths) in the country. Takaragawa Onsen is a popular day-trip destination and one of the closest mixed-gender bathing hot springs from Tokyo. more

The quality of water in the hot springs at Minakami Onsen is different in every bath, but the most notable is the calcium sulphate water that is clear and colourless. It is said to be good for treating bruises, cuts, wounds such as burns, and even breakouts of acne and rashes on the skin.
In recent years, a number of activities have been growing in the region, from rafting and canoeing on the Tone River, to skiing and snowboarding on the slopes of Mount Tanigawa. 

Nasu Onsen is the name of a group of hot springs in the highlands below Mount Nasudake in Nasu district of Tochigi Prefecture. It can be accessed in about an hour and a half by train from Tokyo and offers over 10 bathing facilities and nearly 30 inns, making it a wonderful hot spring getaway. The hot spring baths of Nasu were discovered during the Nara period (710-794) and have been highly regarded for their restorative properties ever since. However, it is said that Shika no Yu hot spring first opened in the year 630. The atmospheric Shika no Yu indoor bath has multiple wooden tubs of varying temperatures.

Historically, Nasu Onsen has been referred to as a hot spring that helps to cure illnesses. The qualities of the hot springs vary by bathing facility, so it’ a good idea to hop around a few hot springs during your visit. more

Nikko-Yumoto Onsen refers to several hot springs located at the foot of Mount Nantai, a sacred, extinct volcano in Nikko National Park. Nikko-Yumoto Onsen area offers an abundant natural scenery to visitors where they can both enjoy a hot spring experience and practice outdoor activities.
Nikko-Yumoto Onsen is a nice place where you can enjoy hot springs in the bubbling source spring area just a short drive (70 min.) from Nikko Station. The relaxing onsen town has many types of accommodation including riverside hotels, Japanese-style inns, pensions and other various types of lodgings. A lot of them offer access to their baths to non-staying visitors. The hot springs water at Nikko-Yumoto Onsen is loaded with sulphur, giving it a milky-white colour and making bathers’ skin lusciously smooth. This is why the hot springs are also named Bijin-no-Yu or “the hot spring of the beauty”. more
The rich sulphur water improves circulation and is also thought to alleviate nerve pain and women’s diseases, in addition to curing fatigue and sensitivity to cold.
First, try out the Yumoto Onsen, where the entire area has the smell of sulphur. Beside the onsen town, you will see Lake Yunoko, a body of water that was formed from damming due to an eruption of the Mitake volcano to the northeast. A popular tourist spot where the waters of Lake Yunoko fall is Yudaki waterfall with a length of 110 metres and a height of 70 metres. Other hot springs in the area are Chuzenji Onsen at the shores of Lake Chuzenji and Kotoku Onsen.
Located halfway up Mount Haruna at an elevation of 700 m, Ikaho Onsen is well known for its stone stairs leading through the town centre and its thermal waters. The 300-metre long path with 365 stone steps at the centre of the resort creates a unique atmosphere and makes Idaho the perfect spot for exploration. You will discover the wonderful effects of the Ikaho Onsen, which are of two types: “Kogane no Yu” (Golden hot springs) and “Shirogane no Yu” (Platinum hot springs). The iron contained in the “Kogane no Yu” water has oxidized to form a distinctive brownish colour and it is said that bathing in these waters helps to ease paints in your joints, muscle pains, relieve fatigue and enhance your appetite. On the other hand, “Shirogane no Yu” water contains silicic acid and is said to help recover the energy after illnesses, more
relieve fatigue, etc.
Ikaho Onsen together with Kusatsu, Minakami and Shima Onsen are the four most famous hot spring resorts of Gunma Prefecture. The first one is also known as the birthplace of onsen manju (steamed bean-jam buns).
Located within easy reach of Tokyo along the Kinugawa River in Tochigi Prefecture, Kinugawa Onsen has grown into one of the most developed hot spring resorts in Japan. Huge ryokan buildings line the Kinugawa River, while interesting theme parks such as the Tobu World Square and Nikko Edomura provide more entertainment nearby.
Kinugawa Onsen is close to Nikko and is a good place to spend the night after visiting Nikko. It will add fun and relaxation to complement the culture and nature of Nikko. There are many open-air baths and footbaths available, where visitors can enjoy the view of the Kinugawa river and the gorge. Kinugawa Onsen has an alkaline spring water that is colourless and transparent. It is said to relieve tiredness and stress and refresh your tired body, being safe for children and older adults as well. more

In the proximity of the onsen you will see many beautiful sites such as the World Heritage Site Nikko Toshogu Shrine, as well as the popular Nikko Edomura and the Tobu World Square. 
Shiobara Onsen is a hot spring town located in a steep forested valley twenty kilometres south of Mount Nasudake. Although Shiobara Onsen is a quite built up hot spring town with several large hotels, it is surrounded by woods and mountains conferring it a pleasant rustic feel. The town has multiple good baths, beautiful waterfalls and multiple pedestrian suspension bridges that offer nice views over the water and surrounding forest.
Along the freshwater river called Hoki, you can visit eleven hot springs and hot spring inns including Fukuwata Onsen, Shiogama Onsen, Shio no Yu Onsen, Nakashiobara Onsen, etc. that have various mineral qualities, and it’s recommended to try out the different waters. For example, the waters of Fukuwata Onsen, Shiogama Onsen, and Shio no Yu Onsen contain sulphate, which is said to help cure burns, more
cuts, and other dermatological problems, while Nakashiobara Onsen is a simple spring that is thought to cure cuts, dermatological problems and soothe gynaecological issues.
Shima Onsen that literally means “Forty-thousand hot springs” is a hot spring town stretching along the Shima River Valley in the mountains of northern Gunma Prefecture. It feels calmer and less developed than many other hot spring towns and has over 40 separate hot spring sources within its borders. Despite its dozens of ryokan, public bathhouses, footbaths and hot spring water drinking fountains, Shima has managed to keep a small-town atmosphere.
The quality of the hot springs is great and it was once said that they are effective against forty thousand types of illnesses, as the name of the onsen implies. It was designated as a national hot spring area for recovery in 1954, along with Sukayu Onsen in Aomori and Nikko Onsen in Tochigi. The hot springs are said to help cure illnesses both by bathing in the water that heals cuts, more
neuralgia and relieves fatigue and by drinking the water that is good for the stomach and helps to increase the appetite.