Spas with adults only in Japan

Tokyo

Private-room head spa salon in Minami-Aoyama, Omotesando, offering 90- to 210-minute scalp treatments from roughly ¥24,750.

Yufuin, Oita

A small hillside ryokan near Yufuin's town center where every room has its own half-open-air bath filled with 100% source hot-spring water and a view of Mt.