Zao Onsen is one of Japan’s most historic hot spring resorts, with a history said to date back more than 1,900 years. Located at an elevation of approximately 880 meters on the western foothills of the Zao Mountains in southeastern Yamagata City, it is one of the most famous hot spring destinations in the Tohoku region.
In the past, the area was known as Takayu or Mogami Takayu. Together with Shirabu Onsen in Yamagata Prefecture and Takayu Onsen in Fukushima Prefecture, it was traditionally counted among the Three Takayu Hot Springs of Oshu.
According to tradition, the hot spring was discovered around 110 AD by Kibi no Tagayu, who accompanied the legendary Prince Yamato Takeru on his eastern expedition. During the Edo period, Zao Onsen flourished as the western gateway to Mount Zao’s religious sites and already had many of the features of a resort destination.
During the Taisho period, roads connecting the hot spring settlement with the surrounding foothills were improved, while streetlights, a police post, and other facilities were introduced. In the Showa period, the opening of ski facilities, the construction of ropeways, and the development of mountain roads further transformed Zao into a major tourist destination.
Today, the resort has a wide range of accommodation, from historic Japanese inns to hotels, pensions, and family-run lodgings. Including corporate recreational facilities, there are more than 120 accommodation and related facilities in the area.
The Sukawa River flows through the hot spring town, and upstream stands Sukawa Onsen Shrine, a shrine dedicated to the hot spring. With public bathhouses, day-use bathing facilities, and the adjacent Zao Onsen Ski Resort, Zao has developed into one of the largest all-season mountain resorts in the Tohoku region.
Zao Onsen is particularly famous for its abundant hot spring water and strongly acidic sulfur-rich waters. The mineral-rich baths have traditionally been associated with benefits for the skin, and the resort has long been known by the nickname “Hime no Yu,” or “Princess’s Hot Spring,” because of its reputation for beautifying the skin.
Walking through the atmospheric hot spring town with steam rising from the baths and streets, visitors can enjoy bathing in the mineral-rich waters while relaxing in the mountain environment.
Zao Onsen is a strongly acidic sulfur spring. Its official spring classification is an acidic, sulfur-containing aluminum-sulfate-chloride spring. The source temperatures range from approximately 45°C to 66°C.
The resort draws water from 47 individual hot spring sources belonging to five source groups. The total flow is approximately 5,700 liters per minute, equivalent to about 8,700 tons per day.
The strongly acidic water has traditionally been valued for its cleansing and skin-related properties. Because of its reputation for helping to keep the skin smooth and bright, Zao Onsen is also called “Hime no Yu” and is sometimes promoted as a “beauty bath.”
The sulfur-rich waters are traditionally valued for their strong cleansing and antibacterial properties and have long been associated with maintaining healthy skin.
Zao Onsen is often described as a “beauty bath” or “beauty-making hot spring” because of its long-standing reputation for leaving the skin feeling refreshed and smooth.
The warm mineral-rich water helps the body feel deeply heated and relaxed. Traditional descriptions of the spring also associate bathing with improved circulation and general relaxation.
Zao Onsen has three traditional public bathhouses where visitors can enjoy the famous waters in a simple and local setting. All three are located within approximately three minutes on foot of one another, making it easy to enjoy a small hot spring tour around the town.
Kamitoyu, or the Upper Bath, is one of the three traditional public bathhouses in the resort.
Shimotoyu, or the Lower Bath, is another of the traditional community bathhouses where visitors can experience Zao’s strongly acidic hot spring water.
Kawarayu is the third public bathhouse and is located close to the other two, making all three convenient to visit on foot.
The Zao Mountains stretch along the border between Yamagata and Miyagi prefectures and form one of the region’s most distinctive mountain landscapes. The area is designated as a Quasi-National Park.
In summer, one of the most famous sights is Okama Crater Lake, a spectacular volcanic lake whose mysterious appearance changes with the weather and light. The emerald-colored water surrounded by the rugged volcanic landscape is one of the signature views of the Zao region.
Winter transforms Zao into a major snow resort. The Zao Onsen Ski Resort is one of the largest ski areas in the Tohoku region and attracts skiers and snowboarders from Japan and overseas.
Another spectacular winter attraction is the phenomenon known as the “Snow Monsters,” or Zao Juhyo. These extraordinary formations are created when heavy snowfall and freezing winds cover trees with thick layers of ice and snow.
The Snow Monsters are generally at their most impressive from January through February, particularly around the summit of Mount Jizo.
You do not need to ski or snowboard to see them. The Zao Ropeway provides access to the mountain area, allowing visitors to enjoy the Snow Monsters from above. Special events such as nighttime Snow Monster illuminations are also held during the winter season.
At the far end of the Zao Onsen town is the famous Zao Onsen Large Open-Air Bath. Built in a four-tiered, staircase-like arrangement beside the mountain stream, the bathing area has a combined capacity equivalent to approximately 100 traditional tatami mats.
The upper two pools are reserved for women, while the lower two pools are for men. The entire facility can accommodate approximately 200 bathers at the same time.
The bath is generally open from 6:00 a.m. to 7:00 p.m. It closes during the winter period from December through April.
Surrounded by forest and the sounds of flowing water, the open-air bath offers a particularly atmospheric way to experience Zao’s hot spring culture.
The name and history of Zao Onsen are associated with the tradition surrounding Karita Mine Shrine in Togatta Onsen, Zao Town, Miyagi Prefecture.
According to legend, the hot spring was discovered around 110 AD by Kibi no Tagayu, who is said to have accompanied Prince Yamato Takeru during his eastern expedition. The hot spring subsequently became known as Takayu, a name that is also reflected in the local Yamagata dialect.
Sukawa Onsen Shrine has been worshipped in the Zao Onsen area since ancient times, reflecting the long-standing connection between the hot spring and local religious traditions.
A historical guide published in 1855, known as the Toko Shonin Kagami, included an illustration titled “Map of Mogami Takayu Hot Spring in Murayama District, Ushu.” This provides a glimpse into the reputation of the resort during the late Edo period.
By the end of the Taisho period, Zao Onsen had approximately 17 traditional inns and welcomed around 130,000 bathers per year.
In 1950, Zao Onsen was selected as the number-one destination in the mountain category of the “New Japan Top 100 Tourist Destinations” competition organized by the Mainichi Newspapers. Following this recognition, Horita Village in Minamimurayama District was renamed Zao Village, and the former name Takayu was changed to Zao Onsen.
Yamagata City incorporated Higashizawa Village in 1954 and Zao Village in 1956. Zao Onsen consequently became part of Yamagata City and gained a reputation as a secluded hot spring destination within the city.
Further developments increased its importance as a tourist destination. The Zao Echo Line opened in 1962, the Zao Mountains were designated Zao Quasi-National Park in 1963, and Zao was selected as one of Japan’s famous mountain destinations in 1964.
During Japan’s period of rapid economic growth, Zao Onsen expanded as a highland resort. The ski area was enlarged, while roads, railways, and other transportation infrastructure were improved.
Around the period of Japan’s economic bubble, a series of transportation developments dramatically improved access to the region. In later years, Zao Onsen also became increasingly popular among international visitors arriving through Sendai Airport.
According to historical tourism data from 2006, approximately two-thirds of Yamagata City’s foreign visitors visited the Zao Onsen area. Korean visitors in particular were an important international market for the resort, especially during the ski season.
Zao Onsen Large Open-Air Bath
Public Bathhouses: Kamitoyu, Shimotoyu, and Kawarayu
Sukawa Onsen Shrine
Hütte Yaren — the former mountain retreat of Jiro Shirasu
Shiginoya Pond
Hai Lake
Yamagata Sake Museum
These sites provide different ways to experience Zao, from traditional hot spring culture and local religious history to mountain scenery and Yamagata’s sake-making traditions.
Ig amochi is a traditional sweet associated with Zao Onsen. It consists of a sweet red bean paste filling wrapped in a soft rice cake.
The simple combination of chewy mochi and smooth anko, or sweet red bean paste, makes it a popular traditional treat to enjoy while exploring the hot spring town.
Karakarajiru is a local soup made with taro, pork, and sake lees. It was developed with the cooperation of Jutaro Nishimura, who operated a restaurant in the local area.
The dish was originally called “Zao Gongen Karakarajiru.” The artist Taro Okamoto, who was staying in Yamagata while skiing, is also said to have contributed to the naming of the dish.
Its hearty ingredients and distinctive sake-lees flavor make it a regional specialty closely associated with the food culture of Zao Onsen.
Zao Onsen is especially appealing because its hot spring culture and mountain attractions can be enjoyed throughout the year.
As the snow melts, the mountains become a destination for hiking and nature walks. The surrounding forests and mountain scenery provide a refreshing contrast to the warm waters of the hot spring town.
Autumn brings colorful foliage to the Zao Mountains. The forests surrounding the hot spring town and mountain trails offer opportunities to enjoy the changing colors while also experiencing the resort’s traditional baths.
Winter is one of Zao’s most distinctive seasons. Skiers and snowboarders come to the large Zao Onsen Ski Resort, while visitors who prefer sightseeing can ride the ropeway to see the famous Snow Monsters.
After enjoying the snowy mountains, returning to the hot spring town and soaking in the strongly acidic waters provides a classic Zao winter experience.
Zao Onsen combines an ancient hot spring tradition with spectacular mountain scenery and a major winter resort. With a history of more than 1,900 years, abundant sulfur-rich waters, traditional public bathhouses, historic inns, and a distinctive hot spring town atmosphere, it offers a different experience from modern resort destinations.
For international travelers, Zao is particularly interesting because several aspects of Japanese culture come together in one destination: onsen bathing, mountain worship, traditional Japanese inns, local cuisine, skiing, and dramatic winter landscapes.
Whether relaxing in a traditional bath, walking through the steaming streets of the hot spring town, hiking through the Zao Mountains, or taking the ropeway to see the Snow Monsters, visitors can experience both the long history and the changing natural beauty of this remarkable mountain resort.
45 minutes by bus from Yamagata Station [18km].
30 min. by car from Yamagata Zao IC of Yamagata Expressway[18km].