Information checked: October 14, 2026. Facility rules and prices change, so always confirm with the facility before you go. A private onsen in Japan is a bath that you or your group can use without sharing it with other guests, either for a reserved time slot or during your stay. Check whether it uses natural hot spring water, because not every private bath does. In Japanese it is usually called kashikiri-buro (貸切風呂, “reserved bath”) or kazoku-buro (家族風呂, “family bath”). Because you are not sharing the water with strangers, couples and families can usually bathe together, and many travelers who feel …