If you are going to use tiles, choose non-porous bathroom tiles like ceramic or porcelain. Porous tiles, such as slate, marble and limestone need sealing every few months to prevent water damage. Only use floor tiles specifically for bathrooms on the floor so they aren’t
It’s also worth raising the bathroom door threshold by about 5mm from the floor in case the room fills with water (if someone covers the shower drain with a towel, for example). This will keep the water contained.