In many Japanese lodging facilities, each room is equipped with yukata (light cotton kimono), loungewear, and slippers to wear in the room. These are provided to help you relax in your room. Therefore, you are asked to generally refrain from wearing them in common spaces. Hotel restaurants, in particular, are often used by non-guests, so please observe the facility dress code.
However, in some accommodations, it is possible to wear the provided yukata in the bathing areas and restaurants. Therefore, if you wish to wear a yukata, please check with the facility staff to see if this is possible. Please note that yukata, loungewear, and other provided clothing and slippers (except those that are one-use only) cannot be taken home.