Unzen Onsen

What to know

Unzen Onsen (雲仙温泉) is a hot spring resort town near the summit of Mount Unzen. Not far from Nagasaki, the area originally grew as a temple town that at its peak rivaled Koyasan in size. During the Meiji Period, it became one of Japan's first tourist resorts popular with foreigners, and a touch of Western influence still lingers. Its location makes Unzen Onsen an excellent base for exploring Mount Unzen.

The resort is surrounded by hot spring fields on several sides. Known as hells (jigoku), these barren rocky areas are dotted with steaming vents and gushing springs where milky, acidic, sulfurous water bubbles straight from the ground. The hells were once used to execute rebels after the failed Shimabara Rebellion, but today the spring water has the more pleasant role of warming visitors in the town's ryokan baths.

A network of paved trails winds through the hells, passing steam vents, hot spring pools, mud holes, and viewpoints. Along the way, shops sell souvenir photos and onsen tamago (soft-boiled eggs cooked in the hot springs). The hells are especially beautiful from late October to mid November, when the surrounding hills are covered in autumn colors (koyo).

Across the road lies an older, dormant hot spring field with trails leading to Manmyoji Temple, the Buddhist temple that once dominated the town but is now rather small and ordinary. At the other end of the dormant field is the Unzen Visitor Center, which features displays on the disastrous eruption of Mount Unzen and its impact on daily life, local plants and wildlife, and an interesting exhibit on hot springs explaining different types and how they form.

There are also several public hot spring baths in Unzen Onsen where day-trippers can try the highly acidic waters. The town's hotels and ryokan have their own baths for guests. Below is one of the public baths found around town:

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