Beppu's Hot Spring 'Hells' and Yufuin: Oita's Onsen Country

Beppu has more hot spring output than any other city in Japan, spread across eight distinct spring areas known collectively as Beppu Hatto. The novelty circuit here is the 'jigoku,' or hells — a set of colorful, boiling, mineral-stained pools you view rather than bathe in — alongside plenty of ordinary public and ryokan baths you can actually soak in.

A short train or bus ride inland, Yufuin is a quieter mountain onsen town with a view of Mount Yufu, known for ryokan stays and a main street that's grown fairly touristy with craft shops and cafes. It works well as a day trip from Beppu or as an overnight if you want a slower pace.

Wash and rinse thoroughly before getting into any communal bath, and don't bring a swimsuit in — most onsens don't allow them. Some facilities still restrict visible tattoos; policy varies by establishment, so it's worth checking ahead if that applies to you.