You should not suppose that a watch with marking “water resistant”is designed for swimming or even diving. This is a wrong opinion, because water resistance of timepieces differs. With a water resistant wristwatch on your wrist you ought not worry if it contacts with water, however, you should remove such a wristwatch before swimming, because very few timepieces are really water-resistant.
It is very important to read all markings on the wristwatch carefully and to know what they mean. The marking “waterproof” or “water-resistant” 3 ATM (30 m) means that your timepiece will withstand contact with water, but you must not swim with such a wristwatch. There are wristwatches with higher resistance to water – to 50m, you should remove such a wristwatch if you plan to dive, but such a watch will withstand swimming. Only watches that have water-resistance of 10ATM (100 m) and more are designed to dive with.
Also lots of persons think that replica timepieces are highly water-resistant, but this is a big mistake. If you are going to buy a timepiece for diving, you should select a genuine wristwatch, for instance a Rolex timepiece, but not a Rolex imitation timepiece. A replica Rolex wristwatch is only a duplicate of a real Rolex watch, but it does not have all the features of the original Rolex timepieces. You should understand that you will not be able to return your watch for refund, if it was damaged by water, no matter if it is a genuine timepiece or if it is from a catalogue of counterpart timepieces.