Comparison
Apnea CWT vs inDepth Apnea: freediving apps for Garmin compared
Apnea CWT is a well-known freediving app for Garmin watches — two clean data screens, automatic dive switching, a buddy mode. inDepth Apnea Blue does that and everything around the dive: five surface-rest safety models, a dive history on the wrist, per-dive graphs on your phone, marked spots on a map. This page compares both fairly — what each app does well, where they differ, and which one fits your training.
What Apnea CWT does well
Apnea CWT, by developer Charles Rincheval (apnea.me), is "the vertical freediving app": a Connect IQ application for constant-weight training that shows surface time, immersion time, heart rate, current depth and vertical speed at a glance, and switches to an immersion view automatically when you dive. It has a few things inDepth does not:
- A buddy mode that times a partner's immersion and counts their dives from a separate page — useful on the edge of the pool or on the platform.
- Cadence vibration alerts — periodic buzzing during immersion and recovery (10 s to 2 min intervals), so you feel the rhythm of the cycle without looking at the watch.
- A wider watch list that reaches Forerunner, Venu and Vivoactive models — though the apnea.me compatibility list itself marks most of those "not fully functional" because of Garmin's firmware depth clamp.
It is a compact, honest app with a long history — the project has been maintained since 2019 in English and French. One practical difference: Apnea CWT is a paid app, listed at €12.00 per watch, while inDepth Apnea Blue is free — no purchase, no ads, no subscription, on as many watches as you like. For a freediver who only wants two screens and nothing else, it is still a reasonable choice.
Where inDepth Apnea goes further
inDepth Apnea Blue is built around a different question. Two screens tell you what is happening; they do not tell you whether it is safe to dive again. That gap — the one that matters most between dives — is where inDepth focuses:
- Five surface-rest models. After every dive, the surface screen recommends a rest and counts it down: 2× dive time, 3× dive time, Adaptive (AIDA 4 guidance), Taravana (a cumulative nitrogen-load model with conservative levels) and Molchanovs (the bar × dive-time rule). Apnea CWT shows surface time; it does not evaluate it.
- A dive history on the wrist. The watch keeps your recent sessions, a session summary (deepest, longest, dives, intervals) and a per-dive review with a second-by-second depth graph, descent/ascent rates, hang time and bottom heart rate — no phone needed to look back at the last dive.
- A free phone app and browser logbook. Every session syncs over Bluetooth to the inDepth app (iOS and Android), with depth/BPM/velocity graphs per dive, session notes, annotations (LMC, samba, early turn…), personal-best trends and a full logbook on the web. Export to CSV or FIT, back up and restore.
- Hang detection. inDepth recognises the hang phase at the bottom plate and highlights it in the dive profile — the number that shows whether your CWT is actually productive.
- GPS spot marking. Mark reef, wreck, entry or hazard with a labelled GPS fix; spots sync to the phone map and to Garmin Navigate.
- Configurable depth alarms. Five alarm slots plus a target depth, each with direction, audio and vibration settings and a preview — a deeper alarm set than a single over-depth alert.
- Pool apps too. inDepth Apnea Pool covers dynamic apnea (DYN, DYNB, DNF, STA) with automatic turns, per-length splits, heart-rate charts on the wrist and workouts built on your phone.
Side by side
| Apnea CWT | inDepth Apnea Blue | |
|---|---|---|
| Price | €12.00 per watch (paid) | Free — no purchase, no ads, no subscription |
| Live depth, surface time, dive counter | Yes | Yes |
| Automatic surface/immersion switching | Yes | Yes — adjustable dive-start depth (0.5–3 m) |
| Surface-rest safety models | No | 2×, 3×, Adaptive (AIDA), Taravana, Molchanovs, Manual |
| Dive log on the watch | Session maxima + upload for website charts | Last 10 sessions with per-dive graphs, rates and hang time |
| Phone app | No | iOS and Android logbook, trends, annotations, backups |
| Web logbook | Charts after activity upload | Full logbook editing, trends, spots map, FIT/CSV export |
| Depth alarms | One over-depth alert + dive-detection depth | 5 alarms + target depth, per-alarm audio/vibration |
| Hang detection | No | Yes, per dive |
| GPS spot marking | No | Labelled marks, synced to the phone and Garmin Navigate |
| Buddy mode | Yes | No |
| Dynamic apnea app | Separate Apnea DYN app | inDepth Apnea Pool — DYN, DYNB, DNF, STA |
| Devices | Fenix 3–8, Descent Mk1–Mk3, Forerunner, Venu, Vivoactive (many marked not fully functional) | Fenix 5–8, Descent Mk2/Mk3 (all fully supported) |
| Languages | English, French | English |
| Distribution | Sideload from apnea.me (not on the Connect IQ store) | Free installer for macOS/Windows over USB, or manual sideload from in-depth.app |
About depth on Garmin watches (it hits both apps)
Garmin firmware clamps the depth reading that any Connect IQ app can see on several watch families — near 3 m on Fenix 7 and the Descent Mk2/Mk3, near 7 m on Fenix 6-class hardware. That is not something either developer can fix; it is a Garmin policy. The difference is how the app treats it: on a clamped watch inDepth tells you your watch's measured ceiling, and switches off the depth-driven safety models rather than show you a dive profile that ends at 3 m. The measured Connect IQ depth table lists every watch we have instrumented. On the Fenix 5, Fenix 5 Plus and Fenix 8, both apps read true depth.
inDepth Apnea Blue is a freediving aid, not a medical device and not a substitute for trained buddy supervision. No algorithm removes the risks of freediving. Never dive alone, always follow the one-up one-down rule, and treat every rest recommendation as a minimum.
When Apnea CWT is still the right choice
- You dive with Forerunner, Venu or Vivoactive hardware that inDepth does not target.
- You want a buddy mode on the watch to time a partner's immersions.
- You want the interface in French.
If your diving is constant weight on a Fenix or Descent — and you want the watch to answer "how long until my next dive?" instead of just "when did the last one end?" — install inDepth Blue and see with your own sessions. It costs nothing to try, and your dives stay on your own devices.
Getting inDepth Apnea
Grab the free installer for macOS or Windows from the download page and connect your watch over USB — the installer puts the app on the watch in a minute. Supported-device details are on the help page, and the inDepth Blue user guide walks through a first session.