Genuine divers watches are designed to be worn and used in or under water. So it means that you can use the watch safely and water should not penetrate it. A typical divers watch has water resistance of around 200 to 300 meters (660 to 990 feet), although the latest technology allows diving watches to be used at greater depths. A pukka divers watch meets ISO 6425, this stipulates features and test standards which are suitable for watches used for diving underwater at depths of more than 330ft. Watches that meet ISO 6425 mark are shown with the word "diver's" so that one can differentiate the diving watches from lookalike watches, which are not really made for serious underwater use.

You can wear non-divers watches for swimming or scuba diving, but if you do wish to use the watch for scuba diving, then you must read the manual or check its water resistance figure before using it, otherwise you risk a ruined watch. There are many fake watches in the market which display the logo of a diver watch. However these watches are usually of inferior quality and will fail to meet the relevant standards.

A divers watch should have certain features. Obviously it should have the correct water resistance rating, even if not rated to ISO 6425. When you look for any water resistant watch, you should check what the rating is to see it can be used for. Ratings such as ‘water resistant to 50 m’ doesn’t mean that it can be used underwater up to a depth of 50 m at all. The user's guide to the watch should make it clear what you can use the watch for, but won't recommend using at the depth of its water resistant figure. This is because the watch was rated theoretically when both the water and the watch were still. Thus it is not to be worn or used at the depth of the figure of water resistance indicated. A common misunderstanding.

Another feature which you should understand about the diver watch is whether the case back and crown is the ‘screw down’ type or not. Lesser designs only have a "push down" crown i.e. you can change the time without unscrewing the winder or crown first. So if you get a divers watch, a push down crown is not likely to be as good as one with a screw down one. If the watch only has a push down crown, there is more chance of water entering into the watch when you go underwater.

One other feature is that a divers watch should have a unidirectional bezel, the bezel is the rotating ring that surrounds the dial face, this for safety reasons. The bezel provides a way of more easily seeing how long you have spent underwater, elapsed time, rather than trying to remembering a time of entry and calculating it. When you see true divers watches, those built solely for diving, they are much larger than normal watches, not something to wear everyday. Diver's watches are designed to be worn over wet suits or dry suits and to be easy to read in poor visibility, so straps are longer and don't have sharp edges and dial faces are bigger.