TomTom GPS watches are water-resistant (5 ATM). You can swim with these watches. However, the built-in Heart Rate Monitor does not work under water.
Before you start a swimming activity, you should check the POOL SIZE setting for the pool where you are swimming. This setting is the length of the pool in metres or yards.
As you swim, your watch registers your strokes and the number of turns you make in the pool. To calculate the distance you have swum and your speed, your watch uses the pool size and the number of turns you have made. If the pool size is not accurate, the metrics for your swimming activity cannot be worked out correctly.
Note : The swim activity only works in a pool.
After swimming, rinse your watch with tap water and dry it with a soft cloth.