First, find out whether or not your hotel has any sort of dress code. It's likely you'll be supplied with a robe, slippers and a towel, but this isn't always so. Underneath, make sure you're as comfortable as possible; tracksuit pants, yoga bottoms, loose-fitting T-shirts and sweatshirts are often recommended. Trainers and sports shoes are usually allowed, but confined to dry areas. You may also like to bring a second swimsuit or a change of clothes along with you.