Hot springs in Unzen

A highland onsen in Unzen-Amakusa National Park at around 700 meters elevation. The dramatic sulfurous steam vents known as the Jigoku, or Hell Grounds, are the defining feature: they bubble, hiss, and release clouds of white vapor across the landscape. The water here is strongly acidic and celebrated for its skin-healing properties.

Obama Onsen is a compact hot spring town on the Shimabara Peninsula in Nagasaki Prefecture, sitting at the base of Mount Unzen and looking out toward the Shimabara Straits. The waters here rank among the hottest in Japan, with temperatures reaching 105 degrees Celsius. Along the seafront, a 105-meter outdoor footbath stretches the full length of what is the longest such facility in the country, and it is open to all visitors at no cost.