Both of these watches put a bright display, dive modes, and full smartwatch features on your wrist. But they come at diving from opposite directions. The Apple Watch Ultra 3 is Apple's flagship smartwatch, and it becomes a recreational dive computer when you add an app like Oceanic+. The Garmin Descent G2 is part of Garmin's dedicated Descent dive-computer line, built with dive modes from the start. That difference drives almost every point below.
Quick verdict
- Pick the Ultra 3 if you live in the iPhone ecosystem, dive recreationally within 40 m a few times a year, and want the best everyday smartwatch.
- Pick the Descent G2 if diving is a priority, you want no subscription, you might go beyond recreational diving, or you use Android.
| Feature | Apple Watch Ultra 3 + Oceanic+ | Garmin Descent G2 |
|---|---|---|
| Dive functionality | Via third-party app (e.g., Oceanic+) | Built in |
| Max diving depth | Recreational to 40 m | Beyond recreational limits (see Garmin's specs) |
| Technical diving (multi-gas, trimix, CCR) | No | Yes, per reviews |
| Air integration | No | No native support, per reviews |
| Cost model | Watch + dive app subscription | One-time purchase |
| Freediving | Yes (to 40 m) | Yes, apnea modes |
| Display | Large, very bright OLED | AMOLED |
| Phone compatibility | iPhone only | iPhone and Android |
| Dive-mode battery | Smartwatch-class; charge daily on dive trips | Longer than Ultra in reviews |
| Everyday smartwatch | Best-in-class apps, payments, calls | Strong fitness and health focus |
Diving capability
For a typical recreational dive, say 18 to 30 m on air or nitrox, both do the job. You get depth, time, NDL, ascent-rate warnings, and safety stops, with clear displays.
The gap opens at the edges. The Ultra is limited to recreational diving within 40 m and doesn't support technical diving. The Descent G2, per reviewers, supports multiple gases and technical modes, including trimix and closed-circuit rebreather modes. If there's any chance you'll pursue technical training, the G2 grows with you and the Ultra doesn't. Our depth ratings explainer covers why this matters.
Cost: subscription vs one-time
You buy the Descent G2 once, and its dive functions are included. The Ultra 3 needs a paid dive app for full dive computer features. Oceanic+ is subscription-based, with annual, monthly, and short-term passes. For a diver who goes a couple of times a year, day passes can keep costs low. For a regular diver, subscription fees add up over the years you own the watch. Factor that into your comparison, not just the sticker price.
Air integration
Neither watch offers native air integration, according to reviewers. You'll use a regulator-mounted SPG with either. If wireless tank pressure matters, look at the Suunto Ocean or Garmin's air-integrated Mk-series models. Transmitter options are in our air integration transmitter guide.
Battery life
This is a real practical difference. The Ultra is a powerful smartwatch, and its dive-mode endurance reflects that. On a trip with multiple dives a day, plan to charge nightly. The Descent G2 is also an AMOLED watch, so it isn't a battery marathoner like Garmin's solar models, but reviewers report longer dive-mode endurance than the Ultra. For long liveaboards, battery is a point in Garmin's favor.
Everyday life
Off the boat, the Ultra 3 is the better smartwatch for most iPhone users. It has deeper app integration, cellular options, payments, messaging, and Apple's health features. The G2 is a capable smartwatch with strong fitness, training, and health tracking, and it works with Android. Its app ecosystem and smart features are narrower, but its training metrics are excellent.
Which one should you buy?
Apple Watch Ultra 3
$$$$Best for: iPhone users who dive recreationally and want the best daily smartwatch
With Oceanic+, a clear, capable recreational dive computer to 40 m, and a best-in-class smartwatch the rest of the time. Full details in our {link('apple-watch-ultra-dive-computer-guide','Apple Watch Ultra dive guide')}.
Why it makes the list
- Best everyday smartwatch for iPhone users
- Very bright display and haptic alerts
- Polished dive app experience
Watch out for
- 40 m limit, no technical diving
- Dive app subscription
- Shorter dive-mode battery
Garmin Descent G2
$$$Best for: Divers who want a real dive computer that's also a smartwatch
Built-in dive modes including technical options, no subscription, AMOLED display, and Garmin's fitness platform on iPhone or Android.
Why it makes the list
- No subscription
- Technical diving capability
- Works with iPhone and Android
Watch out for
- No native air integration
- Garmin's apps have a learning curve
Freediving and snorkeling
Both handle breath-hold diving. Oceanic+ on the Ultra includes a freedive mode with haptic depth and time alarms, limited to 40 m. The G2 includes apnea modes as part of Garmin's dive suite. Recreational freedivers will be happy with either. Deeper or competitive freedivers should compare dedicated options in our freediving watch guide.
Ecosystem lock-in
Think about where your data lives:
- Ultra 3: dive logs live in Oceanic+ (or your chosen dive app), and fitness data lives in Apple Health.
- Descent G2: everything lives in Garmin's apps.
Switching later means migrating logs. It's doable, but worth considering if you plan to keep a long-term logbook.
Bottom line
If you're an iPhone user who dives on vacation, the Ultra 3 is the easy pick and the better daily watch. If diving is central to your life, or you want to grow into technical diving, the Descent G2 is the more capable, subscription-free dive computer. Either way, pair it with a proper SPG and know your limits.
Frequently asked questions
Is Apple Watch Ultra 3 or Garmin Descent G2 better for diving?
For diving specifically, the Descent G2 offers more: built-in dive modes, technical diving support, and no subscription. The Ultra 3 is excellent for recreational diving within 40 meters, especially for iPhone users.
Does the Garmin Descent G2 need a subscription?
No. Its dive functions are included with the watch.
Do either have air integration?
Neither offers native air integration, according to reviewers. Use an SPG or consider the Suunto Ocean or Garmin's air-integrated Mk-series.
Can I use the Garmin Descent G2 with an iPhone?
Yes. The Descent G2 works with both iPhone and Android, while Apple Watch Ultra requires an iPhone.