Zao Onsen: Acid Springs, Snow Monsters and a New Ryokan
Hoshino Resorts opens KAI Zao on 15 October, giving Japan’s most surreal ski mountain a ryokan to match.
Foreign skiers in Japan mostly make for Hokkaido or Hakuba. Zao Onsen, in Yamagata Prefecture and about 40 minutes by bus from Yamagata Station, gets much less of their attention than it deserves.
The snow monsters
Zao is famous for its juhyo, the "snow monsters": conifers near the summit coated in alternating layers of wind-blown ice and snow until they become huge, strange figures. You can see them from the ropeways, on snowshoes, or on skis as you ski past. They are usually at their best around mid-February. The Snow Monster Festival runs from late December to late February, with exact 2026-27 dates not yet confirmed, and the trees are lit in color on selected evenings. The resort itself is substantial, with 28 lifts and a longest run of about 10 kilometers, and it is on the Ikon Pass.
The new ryokan
The news this season is KAI Zao, the first Hoshino Resorts property in Yamagata, which opens on 15 October 2026. It has 49 rooms, all with large panoramic windows. Its bathing is organized as a "spiral wellness journey" through hot spring baths, saunas and Jacuzzis that ends on a rooftop terrace with 360-degree views. The water is high-acidity spring water, which Hoshino calls among the most potent in Japan. The interiors use regional craft: safflower-dyed washi paper, Yamagata Dantsu hand-woven textiles and furniture by Tendo Mokko.
How to do it
Come in February for the monsters. Ski the upper mountain in the morning and spend the afternoon in the water. In a ryokan, the bath is the main event.
