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Apple Watch Ultra Limitations for Diving
The Apple Watch Ultra is the only Apple Watch with a depth gauge rated to 40 meters. But it has limitations that every diver should understand before using it underwater.
Depth gauge: hardware facts
The depth gauge is rated to 40 m (certified to EN 13319, the depth-gauge standard; not a dive computer certification). It measures water pressure and converts it to depth. Accuracy depends on water salinity and temperature. The Apple Watch Ultra sensor range is 40 m; DiveOne records depth to 6 m.
Temperature sensor
Apple Watch provides a water temperature reading when the sensor is available. Conditions and device state can affect observations, and DiveOne does not publish an independent accuracy claim.
Battery under water
Continuous depth tracking with screen active has variable battery consumption. This varies with screen brightness, haptic frequency, and water temperature (cold reduces battery performance). DiveOne recommends starting every dive day with at least 80% battery and relying on primary instruments.
What the Watch cannot do
The Apple Watch Ultra does not have: a gas mix sensor, a compass reliable at depth, cellular connectivity underwater, or any decompression calculation capability. DiveOne works within these hardware constraints — we track what the sensors can measure, and we're transparent about what they can't.
DiveOne 1.0.2 is available.
Download the current App Store release and check the status page for verified limits.