Garmin watch recording the wrong distance on your pool swim? Here's how to fix it

Is your Garmin swim watch recording pool swims with the wrong distance? Learn the common causes and how to correct your FIT file using Swim Blueprint.

Why do Garmin watches count the wrong number of lengths pool swim activities?

Garmin watches with the “Pool Swim” workout type don’t typically rely on GPS to track distance. Instead they use built-in accelerometer sensors to keep track of when you reach the end of the pool and start a new length. This is error-prone and can result in inaccurate workout data. Common reasons include:

  • Open turns - touching the wall without doing a flip turn can confuse the sensor
  • Resting at the wall - a long rest period may be recorded as a separate idle length
  • Stopping during a length - the watch might interpret this as the start of a new length
  • Loose or incorrect watch fit - a watch worn too loosely produces noisy accelerometer data
  • Changing stroke mid-length - switching from one stroke to another e.g. freestyle to breaststroke may record two separate lengths instead of one

These common reasons can result in the watch either counting too many or too few lengths. Over a long swim workout they can add up to significant errors in distance swam, resulting in inaccurate pace and other stats.

Changing your swim style can help to reduce the number of errors in your workouts recorded by your Garmin watch. Keep reading to see how you can fix the remaining mistakes.

How to fix wrong swim distance

Garmin doesn’t provide a way to edit workout (.fit) files. That’s where Swim Blueprint comes in. To fix your swim workout:

  1. Export your FIT file from Garmin Connect or another platform (e.g. Strava, Training Peaks)
  2. Open the file in Swim Blueprint using the workout editor
  3. Review the lap and length chart - each bar represents one pool length
  4. If a length is missing, select the bar where the gap occurred and click Split length
  5. If there is an extra length, select two adjacent lengths in the same lap and click Merge lengths
  6. Click Download corrected FIT to save the fixed file

Which Garmin Watches is Swim Blueprint compatible with?

Swim Blueprint will let you fix pool swim workouts recorded on any Garmin watch with this functionality. This includes:

  • Garmin Fenix series, including:
    • Garmin Fenix 8
    • Garmin Fenix E
    • Garmin Fenix 7
    • Garmin Fenix 6
    • Garmin Fenix 5
  • Garmin Forerunner series, including:
    • Garmin Forerunner 970
    • Garmin Forerunner 735XT
    • Garmin Forerunner 245
    • Garmin Forerunner 570
    • Garmin Forerunner 165
    • Garmin Forerunner 55
  • Garmin Instinct series, including:
    • Garmin Instinct 3
    • Garmin Instinct Crossover
  • Garmin Lily series, including:
    • Garmin Lily 2 Active
  • Garmin Swim series, including:
    • Garmin Swim 2
  • Garmin Venu series, including:
    • Garmin Venu 4
    • Garmin Venu X1
  • Garmin vivoactive series, including:
    • Garmin vivoactive 6
    • Garmin vivoactive 5
  • Garmin Enduro 3
  • Garmin MARQ Athlete (Gen 2)

Where can I use the Swim Blueprint FIT file editor?

For best results, we recommend using the Swim Blueprint FIT file editor on a laptop or desktop in a modern web browser (e.g. Chrome, Firefox, Safari).

It can also be used on smartphones or tablets. We suggest rotating the display to landscape for ease of use.