A Historic Hot Spring Town in the Heart of Toyama
Nestled in Kurobe city, Toyama Prefecture, Unazuki Onsen sits at the entrance of the Kurobe Gorge — one of Japan’s most dramatic V-shaped valleys. Founded in 1923, the resort draws its waters from a natural spring upstream, producing mildly alkaline waters renowned as among the clearest in Japan and known for being gentle on the skin.
The hot spring water originates from the upstream Kuronagi Onsen and has earned the nickname “Beauty’s Bath” for its skin-softening properties. Along the Kurobe River, 20 spring sources release mineral water that emerges at 98°C with a pH of 8.15, and the resort produces 3,000 tons of hot spring water per day, supplying ryokan and hotels that line the riverbank.
Beyond the baths, the Kurobe Gorge Railway — originally constructed in 1926 to transport materials for hydroelectric dam construction — has become one of Japan’s most scenic train journeys. The 20-kilometer route winds between Unazuki and Keyakidaira stations, crossing more than 20 bridges and passing through over 40 tunnels. The iconic red Shin-Yamabiko Bridge at the gorge entrance is one of the area’s most photographed landmarks.
The Selene Museum of Art, located in the nearby Unazuki International Center, features work by Japanese artists focused on the natural environment of Kurobe Gorge. Free foot baths are scattered throughout the town, and the retro shopping street offers local crafts, snacks and the area’s beloved craft beer brewed using Kurobe’s famous water.
Best Times To Visit Unazuki Onsen
The hot spring atmosphere of Unazuki Onsen can be enjoyed year-round, while the Kurobe Gorge Railway runs from mid-April to the end of November.
Autumn is the most popular season, when the forested slopes along the railroad turn bright orange and red. The gorge enjoys a long fall color season that typically runs from mid-October to mid-November. Advance reservations for the railway are strongly recommended during this period as tickets sell out quickly.
Summer offers lush green scenery and cool mountain air, making it a welcome escape from Japan’s humid lowlands. Winter, while quieter and without railway service, brings a serene snow-covered atmosphere ideal for onsen enthusiasts looking for a peaceful retreat.