Taking a trip to a spa hotel is about relaxing and logging off from the real world, so take clothes that are casual, loose and easy to wear. Sweatshirts and tracksuit pants are great options. Toweling robes and slippers are classic spa attire, but these are usually provided by the hotel. Considering splashing around in the pool or loosening up with a yoga class or two? Toss some workout gear, trainers and a swimming suit in your bag as well. If your hotel has an on-site restaurant, check if it has a dress code — you may need to bring a stylish outfit to wear to dinner.