GPS wrong on new WatchOS 27

Downloaded watchOS 27 on Sunday on my Apple Watch series 9 and went for a long outdoor run on Tuesday. I had planned the route on map my run to be a half marathon (21.1km) but the distance measured the distance as 29km by the end of my workout. It seems the GPS is totally inaccurate after this latest update, throwing out crucial km splits and other inaccuracies. Is there a way to fix this? I have repaired my watch, reset both watch and phone and reset calibration settings and none have worked. Will there be another update release please.

Posted on Sep 23, 2026 12:02 PM

1 reply

poonam_kumawat

Level 4 (1,080 points)

Sep 26, 2026 11:11 AM in response to HHH92

Since you’ve already reset calibration, reset the Watch and iPhone, and repaired the Watch, I wouldn’t keep repeating those steps.

Apple’s watchOS 27 notes mention improvements to workout distance calculations and route maps, but they don’t list a fix for GPS distance being dramatically overstated during outdoor runs. A 21.1 km route being recorded as 29 km is significant enough that I’d treat this as a possible watchOS issue rather than normal GPS variation.

Check that you’re on the latest watchOS 27.x release.

Apple’s calibration guidance is here: Apple Support — Calibrate your Apple Watch for improved Workout and Activity accuracy