A dive watch is an essential component to any responsible diver's gear. In order to monitor the amount of nitrogen in the body and keep it at a safe level, a diver must keep track of her depth and time underwater. Dive watches can perform both of these functions, but not all watches that are dive-rated do. So, choosing a dive watches that is suitable for your needs, comfort, and style, will involve taking a few basic aspects of the watch into consideration.
Dive watches take three different forms: digital, mechanical, and dive computers. Though you will need a dive computer anyway, many have been made to be worn on the wrist while also incorporating a time-display. This option is especially useful for certain kinds of scuba which require a dive computer backup, including technical diving.
Many digital dive watches are available at any store that sells watches. In fact, if you already have a digital watch, you may notice a "water-resistant" or "water-proof" depth rating to a certain number of meters, often anywhere from 100m to 300m. The minimum depth rating for scuba diving is 200m-- it is absolutely essential for the watch to be above this rating, otherwise the user will risk damaging or permanently breaking the watch while putting herself in danger. These watches tell time for the purpose of scuba-diving through their stopwatch function.
A mechanical/quartz analog watch is typically considered to be the most durable and fashionable scuba-suitable dive watch available. For this reason, these watches tend to greatly vary in price, so considering diving needs and aesthetic needs separately will be especially useful if an analog watch suits the diver in the first place. These watches use a bezel, which is rotated to align with the minute hand to effectively tell elapsed time as the minute hand continues.
Among all of these watches, there will be models with adjustable buckles, velcro, and/or latches, and those without any adjustability whatsoever. As dive watches are, for most divers, long-term investments, it is recommended that a diver purchase a watch that is adjustable to various wetsuit thicknesses. If a diver prefers an unadjustable watch, it is also recommended that the diver try the watch on while wearing her most frequently used wetsuit on the wrist.