Garmin FR970 vs Apple Watch Ultra 3 GPS Accuracy Tested

The5kRunner just published one of the most rigorous GPS accuracy comparisons we've seen: a 10-mile London course, used consistently over a decade, now updated with the Garmin Forerunner 970 and Apple Watch Ultra 3 alongside Polar and Suunto units. That kind of longitudinal consistency makes the data meaningful in a way that one-off reviews simply can't match.

The headline result is that the FR970 scored joint-best in GNSS accuracy across the field. That puts it right at the top tier for runners who train in urban environments where signal bounce off buildings is the real enemy of clean tracks and reliable pace data. Garmin's multi-band GNSS implementation on the 970 is clearly doing its job.

The Apple Watch Ultra 3 struggled on this course. That matters because the AWU3 carries a premium price tag, a dual-frequency GPS chip, and a reputation built partly on outdoor sports credibility. Losing ground to the FR970 and apparently other competitors on a challenging real-world urban route is a concrete data point worth taking seriously if GPS fidelity is a priority for your training.

For triathletes and cyclists who rely on accurate distance splits, or trail runners transitioning into city training blocks, this kind of variance in GPS performance directly affects pace targets and segment comparisons. A watch that reads 0.2 miles long on a 10-mile run is not a minor inconvenience, it corrupts your training log over time.

The FR970 looks like the safe bet for GPS accuracy right now. The AWU3 has strengths elsewhere, but on raw GNSS performance in a demanding environment, the Garmin wins this one.