Garmin Descent™ Mk3i Watch-Style Dive Computer
Garmin’s air-integrated watch-style dive computer with SubWave™ sonar. Monitor up to 8 tanks, exchange diver-to-diver messages underwater, 200m/20 ATM, multi-gas/trimix/CCR/apnea, DiveView™ maps, Dive Readiness Tool, full multisport smartwatch with wrist HR, Garmin Pay, music. 43 mm from $1,399.99, 51 mm from $1,599.99.
Our Take: The Descent Mk3i is the most versatile dive computer Garmin makes. It’s the only device in the lineup that combines air integration, SubWave diver-to-diver messaging, CCR and apnea modes, DiveView maps, Dive Readiness scoring, and a full multisport smartwatch — all in a watch you can wear every day. The SubWave sonar system is what separates the Mk3i from the Mk3. Pair it with up to 8 T2 transceivers ($499.99 each, sold separately) and you get real-time tank pressure, consumption rate, and remaining air time on your wrist. Add diver-to-diver messaging up to 30 meters and group monitoring for up to 8 divers within 10 meters, and you have a communication layer that most dive computers simply can’t offer. The choice between 43 mm and 51 mm comes down to priorities. The 43 mm ($1,399.99) is the everyday watch — compact, light (49.3 g), and still gets 30 hours of dive battery. The 51 mm ($1,599.99 with silicone band, $1,799.99 with titanium band) adds the bigger 1.4″ AMOLED display, a built-in LED flashlight for low-visibility diving, and a massive 66-hour dive battery (40 hours with air integration active). If you dive multi-day liveaboards or want the flashlight, the 51 mm is worth the upgrade. The trade-offs vs. the console-style X50i ($1,499.99): the X50i has a much larger 3″ screen and 11 deco/backup gas slots vs. 5, but has no CCR, no apnea, no smartwatch features, and shorter battery life. The Mk3i’s smaller display shows less data per screen, but you get a device you’ll actually wear 24/7. For the same watch without air integration, the Mk3 ($1,199.99) saves $200.
Why you’d choose the Descent Mk3i
- Pair with Descent T2 transceivers (sold separately) to monitor tank pressure, air time remaining, and consumption rate for up to 8 tanks on your wrist via SubWave sonar. Essential for multi-stage technical dives, cave dives, and dive leaders monitoring a group.
- Exchange preset messages with other SubWave-equipped divers (Mk3i or X50i with T2 transceivers) up to 30 meters away. Monitor tank pressure, depth, and distance for up to 8 divers within 10 meters. A critical safety tool for buddy teams and group dives.
- The 43 mm fits smaller wrists and everyday wear (49.3 g, 1.2″ AMOLED, 30 hr dive / 10 day smartwatch). The 51 mm has a bigger 1.4″ AMOLED, built-in LED flashlight, and 66 hr dive / 25 day smartwatch battery. Both have identical dive and smartwatch features.
- Underwater: multi-gas, trimix, CCR, apnea, DiveView maps, 200m depth, Bühlmann ZHL-16c. On land: wrist HR, Pulse Ox, Garmin Pay, music, 30+ sport profiles, VO₂ max, sleep/stress tracking, smart notifications. One device for your entire active life.
- 20 ATM (200m) depth rating, EN 13319 compliant. Sapphire crystal resists scratches. Carbon Gray DLC titanium or Bronze PVD titanium bezel. Fiber-reinforced polymer case with leakproof metal inductive buttons fully operational at depth.
- Closed-circuit rebreather mode monitors O₂ and CO₂. Apnea and apnea hunt modes for freedivers and spearfishers with variometer feedback. These modes are exclusive to the Mk3 series and not on the X30 or X50i.
- DiveView color maps with bathymetric depth contours for 4,000+ dive sites. The Dive Readiness Tool analyzes sleep, exercise, stress, and jet lag to assess how prepared your body is to dive. Both exclusive to the Mk3 series.
- The 51 mm Mk3i includes a built-in LED flashlight with variable intensities and strobe modes. See and be seen above or below water. One less accessory to carry on every dive. Not available on the 43 mm.
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Who this dive computer is perfect for
- Technical divers who want wireless tank pressure monitoring for up to 8 gases in a wearable form factor with CCR and trimix support.
- Dive leaders and instructors who need to track the tank pressure, depth, and distance of up to 8 divers via SubWave sonar.
- Divers who want one device for both diving and daily life — air integration underwater, smartwatch features on land.
- Freedivers who want apnea and apnea hunt modes plus the ability to add tank monitoring when switching to scuba.
- Liveaboard divers who need the 51 mm’s 66-hour dive battery and LED flashlight for multi-day trips without recharging.
You may prefer a different Garmin if…
- You don’t need air integration → Descent Mk3 ($1,199.99) — same dive modes and smartwatch, $200 less.
- You want the biggest screen with air integration → Descent X50i ($1,499.99) — 3″ console, 11 deco gas slots, integrated dive light.
- You want a budget console dive computer → Descent X30 ($749.99) — no AI, no smartwatch, solid value.
- You need 11 decompression gas slots → the X50i or X30 consoles support 1 bottom + 11 deco/backup gases vs. the Mk3i’s 1+5.
All Variants
| Model | MPN | UPC | MSRP |
|---|---|---|---|
| 43 mm — Carbon Gray DLC Ti / Black Silicone | 010-02753-10 | 753759333058 | $1399.99 |
| 43 mm — Bronze PVD Ti / French Gray Silicone | 010-02753-13 | 753759333089 | $1399.99 |
| 51 mm — Carbon Gray DLC Ti / Black Silicone | 010-02752-10 | 753759332891 | $1599.99 |
| 51 mm — Carbon Gray DLC Ti / DLC Ti Band | 010-02752-13 | 753759332921 | $1799.99 |
Descent Mk3i vs. Mk3 vs. X50i vs. X30
Focus or hover a row label for a plain-English definition. ★ marks the product on this page.
| Feature |
★ Descent Mk3iYou Are Here
|
Descent Mk3Watch (no AI)
|
Descent X50iConsole + AI
|
Descent X30Value Console
|
|---|---|---|---|---|
| Form Factor?Physical type | Watch-style (43 mm or 51 mm) | Watch-style (43 mm) | Console (large-format) | Console (large-format) |
| Display?Screen specs | 1.2″ (43 mm) / 1.4″ (51 mm) AMOLED | 1.2″ AMOLED, 390×390 | 3″ color LCD, 640×360 | 2.4″ color LCD, 320×240 |
| Lens?Protective crystal | Sapphire crystal | Sapphire crystal | Sapphire crystal | Chemically strengthened glass |
| Depth Rating?Max rated depth | 20 ATM / 200 m | 20 ATM / 200 m | 20 ATM / 200 m | 10 ATM / 100 m |
| Deco Algorithm?Decompression model | Bühlmann ZHL-16c w/ GF | Bühlmann ZHL-16c w/ GF | Bühlmann ZHL-16c w/ GF | Bühlmann ZHL-16c w/ GF |
| Gas Mixes?Supported gases | Air/Nitrox/Trimix, 100% O₂; 1+5 gases | Air/Nitrox/Trimix, 100% O₂; 1+5 gases | Air/Nitrox/Trimix, 100% O₂; 1+11 gases | Air/Nitrox/Trimix, 100% O₂; 1+11 gases |
| CCR Mode?Closed-circuit rebreather | Yes | Yes | No | No |
| Apnea / Freediving?Freediving modes | Yes (apnea + apnea hunt) | Yes (apnea + apnea hunt) | No | No |
| NDL Aware™?Depth-to-NDL projection | No | No | Yes | Yes |
| Feature |
★ Descent Mk3iYou Are Here
|
Descent Mk3Watch (no AI)
|
Descent X50iConsole + AI
|
Descent X30Value Console
|
|---|---|---|---|---|
| Air Integration?Tank pressure via transmitter | Yes Up to 8 tanks (T2) | No | Yes Up to 8 tanks (T2) | No |
| SubWave™ Sonar?Diver messaging + monitoring | Yes Messages + monitoring | No | Yes Messages + monitoring | No |
| DiveView™ Maps?Bathymetric maps, 4,000+ sites | Yes | Yes | Yes | No |
| TopoActive Maps?Surface navigation maps | Yes | Yes | Yes | No |
| Surface GPS?Mark entry/exit points | Yes + SatIQ multi-band | Yes + SatIQ multi-band | Yes | Yes |
| 3-Axis Compass?Underwater navigation | Yes | Yes | Yes | Yes |
| Dive Light?Backup illumination | Yes LED flashlight (51 mm) | No | Yes Integrated backup | No |
| Connectivity?Wireless protocols | Bluetooth, ANT+, Wi-Fi, SubWave | Bluetooth, ANT+, Wi-Fi | Bluetooth, ANT+, Wi-Fi, SubWave | Bluetooth, ANT+ |
| Garmin Dive™ App?Dive log sync | Yes | Yes | Yes | Yes |
| Feature |
★ Descent Mk3iYou Are Here
|
Descent Mk3Watch (no AI)
|
Descent X50iConsole + AI
|
Descent X30Value Console
|
|---|---|---|---|---|
| Smartwatch?Health, music, payments, sports | Yes Full multisport smartwatch | Yes Full multisport smartwatch | No Dive-dedicated | No Dive-only |
| Wrist Heart Rate?Optical HR sensor | Yes | Yes | No | No |
| Pulse Ox (SpO₂)?Blood oxygen saturation | Yes | Yes | No | No |
| Dive Readiness?Readiness score | Yes | Yes | No | No |
| Garmin Pay?Contactless payments | Yes | Yes | No | No |
| Music Storage?On-watch music | Yes | Yes | No | No |
| Feature |
★ Descent Mk3iYou Are Here
|
Descent Mk3Watch (no AI)
|
Descent X50iConsole + AI
|
Descent X30Value Console
|
|---|---|---|---|---|
| Dimensions?Physical size | 43×43×14.15 mm (43 mm); 51×51×16.4 mm (51 mm) | 43 × 43 × 14.15 mm | 62.4 × 98.3 × 24.5 mm | 78.7 × 61.8 × 24.7 mm |
| Weight?Unit weight | 49.3 g (43 mm, no band) | 49.3 g (no band) | 253 g (with bands) | 160 g (no bands) |
| Battery (Dive)?Dive mode runtime | 30 hrs (43 mm); 66 hrs (51 mm) | 30 hrs | 16 hrs (medium) | 30 hrs (medium) |
| Battery (AI Dive)?Dive with air integration | Up to 40 hrs (51 mm) | N/A | N/A | N/A |
| Battery (Smartwatch)?Daily smartwatch | 10 days (43 mm); 25 days (51 mm) | 10 days | N/A | N/A |
| Case?Housing material | Fiber-reinforced polymer, DLC titanium or Bronze PVD titanium bezel | Fiber-reinforced polymer, stainless steel bezel | Fiber-reinforced polymer | Fiber-reinforced polymer (recycled ocean plastics) |
| Memory?Onboard storage | 32 GB | 32 GB | 32 GB | — |
| MSRP?Starting retail price | From $1,399.99 | $1,199.99 | $1,499.99 | $749.99 |
Where does the Descent Mk3i fit in Garmin’s dive lineup?
Value Console — Descent X30
- $749.99
- Large 2.4″ console. Bühlmann ZHL-16c, multi-gas/trimix (1+11 gases), surface GPS, compass. 10 ATM/100m, 30-hr dive battery. No CCR, no apnea, no smartwatch, no AI. The most affordable Garmin dive computer.
- View on heartratemonitorsusa.com →
Watch (no AI) — Descent Mk3
- $1,199.99
- 43 mm watch-style. Same dive modes, algorithm, DiveView maps, Dive Readiness, and smartwatch as the Mk3i. No air integration, no SubWave, no messaging. $200 less. Perfect if you read your SPG manually.
- View on heartratemonitorsusa.com →
★ You Are Here — Descent Mk3i
- From $1,399.99
- The most versatile Garmin dive computer. Watch-style with SubWave AI (up to 8 tanks), diver messaging, CCR, apnea, DiveView maps, full smartwatch. 43 mm or 51 mm. The 51 mm adds flashlight and 66-hr dive battery.
- View on heartratemonitorsusa.com →
Flagship Console — Descent X50i
- $1,499.99
- The biggest display (3″ touchscreen) with AI, SubWave, DiveView + TopoActive maps, integrated dive light, 1+11 gases, sapphire. No CCR, no apnea, no smartwatch. The choice for maximum screen real estate.
- View on heartratemonitorsusa.com →
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Descent Mk3i — Frequently Asked Questions
What is the Descent Mk3i?
The Descent Mk3i is Garmin’s air-integrated watch-style dive computer and multisport GPS smartwatch. It pairs with Descent T2 transceivers (sold separately) for wireless tank pressure monitoring via SubWave sonar, supports diver-to-diver messaging, and doubles as a full smartwatch with wrist heart rate, Garmin Pay, music, and 30+ sport profiles. It comes in 43 mm ($1,399.99) and 51 mm ($1,599.99–$1,799.99) sizes. The 51 mm adds a larger 1.4″ AMOLED display (454×454), a built-in LED flashlight, and up to 66 hours of dive battery life.
What’s the difference between the 43 mm and 51 mm?
The 43 mm has a 1.2″ AMOLED (390×390), 30-hour dive battery, and 10-day smartwatch battery in a compact 43 × 43 × 14.15 mm case (49.3 g without band). The 51 mm has a 1.4″ AMOLED (454×454), 66-hour dive battery, 25-day smartwatch battery, built-in LED flashlight with strobe, and a larger 51 × 51 × 16.4 mm case. Both share the same dive features, air integration, SubWave, DiveView maps, and smartwatch capabilities. Choose 43 mm for everyday wearability; choose 51 mm for the bigger display, longer battery, and flashlight.
Does the Mk3i come with a T2 transmitter?
No. The Descent T2 transceiver is sold separately ($499.99). The Mk3i’s SubWave hardware supports pairing with up to 8 T2 transmitters. Some retailers offer Mk3i + T2 bundles. You can also buy the T2 later and pair it any time.
How is the Mk3i different from the Mk3?
The Mk3i adds: SubWave sonar air integration (up to 8 tanks via T2 transceivers), diver-to-diver messaging (up to 30 m), diver group monitoring (tank pressure, depth, distance for up to 8 divers within 10 m), and is available in both 43 mm and 51 mm. The 51 mm has a built-in LED flashlight. The Mk3 (43 mm only, $1,199.99) has no air integration, no SubWave, and no flashlight. Everything else — dive modes, algorithm, DiveView maps, smartwatch features — is identical.
What dive modes does the Mk3i support?
Single-gas, multi-gas (air, nitrox, trimix up to 100% O₂ with 1 bottom + 5 deco/backup gases), gauge, apnea, apnea hunt, and closed-circuit rebreather (CCR). The Bühlmann ZHL-16c algorithm has user-configurable gradient factors.
What is SubWave sonar and how does it work?
SubWave is Garmin’s proprietary sonar-based underwater communication system. It enables: (1) Air integration — monitor tank pressure, air time remaining, consumption rate for up to 8 tanks via T2 transceivers within 10 meters. (2) Diver-to-diver messaging — send preset messages to other Mk3i/X50i divers with T2 transceivers up to 30 meters away. (3) Group monitoring — see depth, tank pressure, and distance for up to 8 divers. Messages require line of sight and may take up to 45 seconds.
What’s in the box?
43 mm: Descent Mk3i dive computer, black (or French gray) silicone band, extra-long adjustment strap, USB-C clip charging/data cable, documentation. 51 mm: Same plus the black silicone band is standard; the DLC titanium band variant also includes a black silicone band. All variants: T2 transceiver is sold separately.
Does the 51 mm Mk3i have a flashlight?
Yes. The 51 mm Mk3i has an integrated LED flashlight with variable light intensities and strobe modes. It works both above and below water. The 43 mm Mk3i does not have a flashlight.
Need help choosing? Call us at 1-800-403-8285 or 215-259-2700. Our team is happy to help you find the right Garmin dive computer.