Hebinyu

High in the hills above Beppu's Myoban district, Hebinyu is a free outdoor bath built beside a mountain stream: four pools stepped down toward the water, each a little cooler than the one above, from roughly 42°C at the top to about 40°C in the lowest one by the river. The water is clear and hot, with leaves and bits of forest floating in it, and there is no fee, no staff and no closing time. A typhoon landslide wrecked the bath in 1997 and volunteers rebuilt it; locals still keep it clean, so take your trash home and leave soap behind.

It is a mixed bath with a simple wooden changing shack and a separate walled changing room for women, and no posted rule on what to wear. Getting here is part of the deal. Drivers face a narrow, rough, partly unpaved road with room for only a handful of cars at the end.

Walkers can take a Kamenoi bus from Beppu Station to Konya Jigoku-mae and hike about an hour, up past a large cemetery and down to a river crossing. Bring water, since there are no facilities. The downside is safety: signs nearby warn of serious crime in the area in the past, and visitors advise going in daylight and not alone.