Yufuin is the most popular day trip from Beppu: a smaller, more refined onsen town about 45 minutes inland by direct train, with a lake, art museums, craft shops, and a mountain backdrop. It is considerably quieter than Beppu and attracts a different crowd — Yufuin has successfully positioned itself as an upmarket alternative to its neighbour's more commercial resort character.
Oita, the prefectural capital just 15 minutes away by train, has Usuki Stone Buddhas — a group of medieval Buddhist rock carvings that are among the finest in Japan — and is worth a half-day if you have time. Further afield, Kumamoto and its reconstructed castle are about 2 hours by train.
