A trip to a spa hotel is about relaxing and escaping the real world, so take clothes that are casual, loose and easy to slip into. Track pants and T-shirts are great options. Toweling robes and slippers are standard spa attire, however these are usually issued by the hotel. Considering going for a dip in the swimming pool or doing a couple of fitness classes? Throw some workout gear, trainers and your bathing suit in your suitcase too. If your hotel has a restaurant on-site, find out if there's any sort of dress code — you may need to bring a smart outfit to wear for dinner.