The primary goal is comfort and practicality while you're staying at a spa hotel, so casual, non-restrictive clothing is what most guests generally wear. While you'll probably spend a good deal of your time in a bathrobe and slippers, these are usually waiting for guests when they arrive. If you want to take advantage of the resort's fitness facilities, pack your activewear and trainers. Hoping to kick back and relax in the swimming pool or hot tub? Don't forget to pack your bathing suit. In addition to toiletries and other personal belongings, bring a change of clothes with you too. It's always good to have a clean, dry outfit to put on after a treatment.