Yes. The race numbers we supply are waterproof and tearproof. Take care when you put your wetsuit on over the numbers; ask a friend to help you. When you take your wetsuit off, your numbers should remain intact, provided you have pinned them securely in all four corners.
Most athletes will either attach their race number to the top that they are going to wear on the cycle/run or use a race belt. If you do not have a race belt, they can be purchased for £6 at the registration tent.