Spa hotels are all about relaxing and unplugging from the real world, so bring clothes that are casual, loose-fitting and easy to slip out of. Tracksuit pants and sweatshirts are a great choice. Slippers and fluffy bathrobes are customary spa attire, but these are usually provided by the hotel. Thinking of splashing around in the swimming pool or doing a workout? Squeeze some gym gear, trainers and a swimsuit in your bag too. If your hotel has an on-site restaurant, see if there's any sort of dress code — you may need to bring a smart outfit to wear for dinner.