Open Water Swim on Watch

Hey DomWilliams,

We recommend that you try calibrating your Apple Watch to improve the accuracy of your records. Here's how:

Calibrate your Apple Watch for improved Workout and Activity accuracy - Apple Support

Calibrate your Apple Watch

1. While wearing your Apple Watch, go to a flat, open outdoor area that offers good GPS reception and clear skies.

2. If you have Apple Watch Series 2 or later, you just need your Apple Watch.* If you have Apple Watch Series 1 or earlier, bring your iPhone for GPS. Hold your iPhone in your hand, or wear it on an armband or waistband.

3. Open the Workout app, then tap Outdoor Walk or Outdoor Run. To set a goal before starting, tap .

4. Walk or run at your normal pace for about 20 minutes.

Let us know how it goes!

Best regards.

DomWilliams,

Calibrate your Apple Watch improves the accuracy of your distance, pace, and calorie measurements. Calibrating your watch can also help it learn your fitness level and stride, which improves accuracy when GPS is limited or unavailable.

Let us know once you calibrate your Apple Watch and if the issue persists.

Cheers!