Unzen Yokayu

Unzen Yokayu is a geothermal area located in Unzen, Nagasaki Prefecture, on the island of Kyushu. The site sits within Unzen-Amakusa National Park, Japan's first national park designated in 1934. The word "yokayu" translates roughly to "boiling water," an apt description for this dramatic volcanic landscape where steam vents, bubbling mud pools, and sulfurous fumaroles create an otherworldly atmosphere.

The geothermal activity at Unzen Yokayu has been documented for centuries, with the area gaining notoriety during the 17th century when it became a site of Christian persecution. Hidden Christians were brought here and subjected to torture by the scalding hot springs, a dark chapter that adds historical weight to the location. Today, the site is recognized not for its tragic past but for its striking natural phenomena and therapeutic hot spring culture.

Visitors can explore a network of walking paths that wind through the active geothermal field, passing over 30 fumaroles that emit steam at temperatures reaching 98-120 degrees Celsius. The trails are well-maintained and take approximately 30-40 minutes to complete at a leisurely pace. The intense sulfur smell permeates the area, and the sight of steam rising against the mountainous backdrop creates a memorable sensory experience. Many visitors purchase onsen tamago, eggs boiled in the hot spring water, from vendors near the site.

Unzen Yokayu is accessible from Nagasaki City via bus, with the journey taking approximately 90 minutes. Buses depart from Nagasaki Station and terminate at Unzen Bus Terminal, located within walking distance of the geothermal area. For those traveling from Kumamoto, buses take roughly 2.5 hours. There is no admission fee to enter the geothermal area itself, making it freely accessible throughout the year.