Taking a trip to a spa hotel is about relaxing and escaping the real world, so pack clothing that is light, comfortable and easy to slip into. Sweatshirts and tracksuit pants are good options. Toweling robes and slippers are popular spa attire, but these are usually provided by the hotel. Planning on soaking your body in the hot tub or doing a few exercise classes? Toss some gym wear, trainers and a swimsuit in your suitcase too. If your hotel has a restaurant on-site, see if it has a dress code — you may need to bring something smart to wear for dinner.