If you are in the market for your first freediving computer, the overabundance of information and specifications for each computer can become overwhelming and leave you feeling confused. Beginner freedivers especially might not be sure of what exactly they need from their dive computers and what features to look for. They may just use a dive computer that is designed purely for scuba and miss out on a lot of useful information that a freediving computer can provide. We take a look at different specifications that are available on freediving computers below.

Current and Maximum Depth

These two pieces of information are the very basic specifications we can ask for from a freediving computer. If you are fun diving off of the line, it is reassuring to be able to look down at your wrist and see how deep you are exactly. It is also useful for training to see your maximum depth, especially if you turned early and want to know where you stopped.

Dive Log

A dive log/history is a very useful element in a freediving computer. The ability to see all of your past dives and keep track of them on the dive computer itself, on a smartphone application, or on your own personal computer can help you analyze your previous dive times, depths, and dive speeds, helping you plan future training objectives.

Dive Time

Freedivers training on a line. Photo by Yahia Barakah.

Knowing your dive time is great for measuring surface intervals, which is something freedivers should watch out for both on and off the line. As you progress in going deeper in the ocean, it’s also useful to know your dive time so you can calculate your dive speed (if your dive computer does not have that specific function).

Ascent Rate

Ascent rates are an important factor that contributes to the risk of decompression sickness for freedivers. This can also be calculated on your own if you have a dive computer that shows your dive time, but dive computers that have this feature built-in can tell you your ascent speed in real-time, saving you the trouble of doing the extra math.

Depth Notifications

This feature becomes incredibly important when you start learning how to freefall. Depth notifications just make a single notification when you reach a specified depth, as opposed to some dive alarms that continue to beep if you stay below the specified depth. Some freediving computers offer the choice between audible and vibration alarms, as well, which is great for freedivers who have a preference.

Surface Interval Time/Alarm

Surface intervals are important to watch out for due to the risk of decompression sickness in freediving. There is a formula for keeping track of your surface interval time after a dive, and with a dive computer that shows you your surface interval time, you can calculate how much time you need to wait before diving again. Some newer dive computers have come out with a surface interval alarm feature. With this feature, you can spend your time freely at your buoy or during the relaxation phase of your next dive and wait to feel or hear the alarm.

Stopwatch

Freediving static training in shallow water.

A stopwatch is an excellent feature for training purposes, such as with static or dynamic CO2 tables. While you can get a separate waterproof stopwatch for your training sessions, it is nice to have this built into your dive computer and avoid having to remember yet another thing to bring with you to the pool.

Rechargeable Battery

Some freedivers do not want to go through the hassle of getting their battery changed every year, especially if it requires going to a store that has to change it for you and pressure test it, which can sometimes take multiple days depending on how much work they have. Computers with rechargeable batteries just need to be recharged by the user, similar to smart/sports watches, and the annual battery change trip can become a thing of the past.

GPS

If you are a spearfisher or have to hunt for underwater buoys or dive sites that are unmarked at the surface, GPS can be an incredible feature for locating certain underwater spots. Certain dive computers with GPS can show you clearly the direction you need to go and how far away you are from the spot. Some dive computers even let you save spots and share them with others who have the same computer, enabling you to also discover new spots near you.

Heart Rate Monitor

A heart rate monitor can be an integral part of your freediving training. It can tell you how fast your heart is beating before, during, and after your dive. These freediving computers will either have the heart rate monitor built into the underside of the watch face or come with a separate strap that you wear underneath your wetsuit against your bare chest.

Final Thoughts

Dive computers become an integral part of your freediving training as you experience deeper depths and take more advanced certification courses. They are the one piece of equipment that you will probably invest most of your money in, but also one that can save your life and help you progress in your training. Make sure to check the specifications of each computer you are considering, read reviews, and ask the recommendations of other freedivers before purchasing a new dive computer.