Apple Watch 10 not tracking open water swim distance correctly

I have noticed recently my Apple Watch 10 is not tracking my open water swims correctly. It seems the route is actually correct but the distance is not even half but just a small portion. I’ve tried updating to the latest OS, wearing it outside of my wetsuit, stopping at idle times, but nothing seems to work.

If it were like this from the moment I bought it, I would just assumed it’s not ideal for open water swims, but it did seem to work fine before, maybe just a slight deviation as expected but not such a big difference. It’s been really annoying as the map seems accurate but the pace and distance are way off, specially comparing to other people’s tracking devices

Posted on Nov 9, 2026 1:40 AM

1 reply

WheelieNick

Level 9 (74,110 points)

Nov 9, 2026 6:17 AM in response to March_Bm

When your Apple Watch Series 10 shows an accurate route map but reports a fraction of the actual open water swim distance, the issue is typically how the watch acquires and maintains a GPS lock each time your arm dips beneath the water.

Submersion and GPS Dropouts: GPS signals cannot penetrate water. Every time your wrist goes under during a stroke, the watch temporarily loses GPS connectivity. It relies on the accelerometer and gyroscope to estimate movement underwater, and if your stroke style keeps your hand submerged longer, the distance calculation drops severely.
GPS Lock Before Starting: If you tap "Start" immediately upon entering the water or before the GPS signal turns completely green/ready, the watch struggles to establish a baseline, leading to truncated tracking.
Environmental or Wrist Factors: Choppy water, overcast skies, tight wetsuit cuffs shifting the watch, or a recent software glitch can affect how fast the watch re-acquires satellites between strokes.