Most spas have separate locker rooms for men and women where you change into a robe and slippers. While some spas have private changing cubicles, many do not and you have to change in front of others. If you"re uncomfortable, you can always change in a bathroom stall. Some spas will invite you to change in the actual spa treatment room.
People generally go to a spa"s relaxation room before or after a treatment in their robe and slippers with nothing, a swim suit, or underwear underneath. Be careful with how you are positioned/sitting in the waiting room, especially if the robe is small for your body size. Many spas have extra large robes but you need to ask for them specifically.
Spas offering these facilities generally incorporate them into the men and women"s locker room area. In that arrangement you can go totally nude, go nude and wear a towel around you, or wear a swimsuit (unless you"re in a country that doesn"t allow swimsuits in these facilities). (See details below.) In coed facilities, one generally wears a swimsuit except in countries like Austria or Germany where coed nudity is the norm.
For popular massages such as Swedish and Deep Tissue most people like to be naked, although if you prefer to wear a swimsuit or underwear you can. The therapist will generally explain the treatment, advise whether you should be face up or face down on the table, and then (and this is the law in some countries) step out of the room while you take off your robe and slip underneath the sheet. The therapist will knock before reentering. When you turn over half way through the massage, the therapist holds the sheet up so they can"t see you. When the massage is over the therapist generally steps out of the room while you get up and don your robe and slippers.
Similar procedure to the massage, however many people wear their robes or a curtain-like towel with Velcro during the facial. Note: because the therapist will massage your upper back, shoulders and dcollet, it"s best to remove any upper body garments that might get in the way.
Some spas offer disposable panties for both hygienic and modesty concerns and they may or may not be required. You are more likely to be exposed during these kinds of treatments.