Why Apple Watch Ultra Only

Apple Watch Series 10 and later provide shallow depth capability to 6 m. Every Apple Watch Ultra model, including Ultra 3, has a 40 m hardware sensor range. DiveOne 1.0.1 limits native recording to 6 m on every supported watch. Models without a depth sensor are not supported.

The Ultra's water temperature sensor provides real-time readings during submersion. Standard models have a skin temperature sensor designed for health tracking on land — it doesn't measure water temperature accurately or at all while submerged.

Apple Watch Ultra is rated WR100 and tested for recreational diving to 40m under EN 13319. Standard Apple Watch models are rated WR50 — suitable for shallow water activities like swimming, but not designed for submersion at diving depths.

We could build a version that works on standard Apple Watch — showing surface time, GPS, and basic session logging. But we won't label that 'dive tracking' because it wouldn't include actual depth data. We'd rather support fewer devices honestly than more devices misleadingly.