Swimming with Apple Watch — Waterproof Performance Tested

Pool laps, open water, heart rate in the water — does it actually work?

The Apple Watch is rated water-resistant, but how does it actually perform during swimming? Willem tested it in the pool and in open water — tracking laps, heart rate, and stroke detection.

The Apple Watch locks its screen during a swim workout (Water Lock mode) and tracks laps automatically using its accelerometer. When you're done, the crown spins to expel water from the speaker.

What it tracks well: lap count in a pool (remarkably accurate), total distance, active calories, and workout duration. The automatic lap detection works by sensing your turns at the wall.

What it struggles with: heart rate in the water. The optical sensor loses contact with your skin when water flows between the watch and your wrist. Readings during swimming are intermittent — you get averages, not continuous data.

For pool swimming, it's genuinely useful. For open water, GPS tracking adds distance measurement but the heart rate limitation remains.

From Willem's writing on wearable sensors and what they can measure.