---
title: "Swimming with Apple Watch — Waterproof Performance Tested"
language: en
topics: ["apple", "sport", "watch"]
full_article_url: https://willem.com/en/2018-09-27_swimming-and-cycling-with-apple-watch/
---
# 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](https://willem.com/en/wearable-sensors-measuring-the-body-questioning-the-data/).