Pixel Watch 5 challenges Apple and Garmin with superior GPS accuracy on London Marathon course

Tested on a challenging London Marathon segment, Google’s Pixel Watch 5 demonstrated notable improvements in GPS precision over the Apple Watch Ultra 3 and Garmin Fenix 8 Pro, marking a significant step forward in urban route tracking technology.

Google’s claim that the Pixel Watch 5 can outperform the Apple Watch Ultra 3 and Garmin Fenix 8 Pro on GPS accuracy sounded bold, particularly to anyone familiar with the reputation of those rival watches for route tracking. But after testing all three on a difficult stretch of the London Marathon course, TechRadar found that the Pixel Watch 5 did make a strong case for itself, especially in the most demanding urban sections around Canary Wharf. The Apple Watch Ultra 3 also performed well, while the Garmin showed the most visible drift and over-read the distance.

The test focused on miles 18 to 20 of the marathon route, an area lined with tall buildings that often disrupt satellite signals. The reviewer ran the section in one direction, then repeated it in reverse, using the native workout apps on each watch and comparing the resulting tracks in IloveGPX. Before the run, the Pixel Watch 5’s route file had to be converted from TCX to GPX, but once the data was plotted, the differences between the watches became clear.

Google’s pitch for the watch rests on more than dual-band GPS alone. According to reporting cited in the article, the Pixel Watch 5 combines dual-frequency satellite reception with Google Maps building data and AI-based correction to reduce errors caused by signal bounce in dense urban areas. Google also says it uses reference stations around the world to improve accuracy when atmospheric conditions interfere with positioning. To save battery life, the watch compresses raw GPS data and processes it off-device before syncing the corrected results to Google Health.

In practice, the Pixel Watch 5 tracked closest to the route actually run, particularly on the second pass through the most difficult Canary Wharf sections. The Apple Watch Ultra 3 stayed competitive and often tracked close to the Pixel Watch 5, but the Garmin Fenix 8 Pro was more prone to wandering off course and recording a longer distance. The article also notes that all three watches struggled with pacing early in the runs, although their pace data settled later.

That leaves the Pixel Watch 5 looking like a genuine step forward for route accuracy, even if the test did not prove that every element of workout tracking is flawless. TechRadar’s verdict was cautious but positive: the watch appears well suited to runners and hikers who value precise maps of where they have been, while pace data may still need refinement. Other hands-on comparisons have reached similar conclusions, with the Pixel Watch 5 coming out slightly ahead of the Apple Watch Ultra 3 and comfortably ahead of Garmin in some urban tests.