A scuba computer is built around decompression. A freediving computer is built around the breath: short dives, many repetitions, and a surface interval that matters as much as the depth. If you freedive, or you do both, here are seven things to look for before you buy.
1. A real freedive mode, not a gauge mode
Gauge mode only shows depth and time. A freedive mode records every descent as part of a session, tracks surface intervals and lets you set alerts per dive. Look for separate depth and pool modes, and for static (STA) and dynamic training.
2. Alerts you can feel
Under water you are not looking at your wrist. Depth and time alerts should reach you by vibration, not only by beeps, and you want several sets: one for warm-up dives, one for target dives. Freefall, keep-depth and surface-time alerts are useful once you train seriously.
3. A display you read in one glance
Big digits and high contrast matter more than a long list of data. A colour display is easier to read in dim water than a segment display, as long as it stays bright.
4. Training tables
CO2 and O2 tables and custom tables let you do dry and pool training with the watch counting for you. Being able to build tables in an app and send them to the watch saves a lot of button pressing.
5. Safety stopwatch and surface interval
A dedicated safety stopwatch and a clear surface-interval count are simple features that make buddy protocols easier to follow.
6. A logbook that groups sessions
Twenty descents in a morning should be one session in your log, not twenty unrelated dives. Check how the app handles this before you buy.
7. Something you will also wear on land
Most freedivers train a few times a week. A computer that doubles as an everyday watch, with notifications, tides and activity tracking, gets worn, charged and synced. One that lives in a bag does not.
How the ATMOS MISSION3 fits
The ATMOS MISSION3 has dedicated Depth and Pool modes, STA, CO2 and O2 tables, custom tables and dynamic training. Alerts for dive time, descent depth and ascent depth come in ten sets each, next to freefall, keep depth, surface time and hydration alerts, delivered on the display, by vibration and by buzzer. It has a freedive safety stopwatch, a 1.4-inch AMOLED display, and the free ATMOS App groups freediving records into sessions and, from firmware 1.108, lets you configure freediving alerts and custom tables from your phone. And it is a scuba computer with Air, Nitrox, Multi-Gas and Gauge modes at the same time, so you do not need two devices.
Want to see one first? Find an official ATMOS dealer.