I wore the Apple Watch Ultra 4 and the Garmin Fenix 9 Pro for a marathon, and this watch won by miles

During my 7th marathon in Frankfurt, Germany, I put the Apple Watch Ultra 4 and Garmin Fenix 9 Pro head-to-head while battling pouring rain and strong winds. The Apple Watch Ultra 4 is Apple's newest rugged sports watch, featuring a new heart rate monitor and a readiness score to help you gauge when to push or recover. The Fenix 9 Pro, on the other hand, is Garmin's most advanced sports watch yet, offering all the sports modes and stats needed to track workouts, along with comprehensive daily activity and sleep tracking.

On race day, I wore both watches and switched them from miles to kilometers, as most European marathons have markers every kilometer. I manually lapped each watch every 5km to ensure accurate pacing data. When I finished the race, I downloaded the data to compare the accuracy of both watches.

While both watches have GPS issues in built-up cities, the Garmin Fenix 9 Pro performed better in recording accurate pace data due to its superior GPS connectivity. My Garmin Fenix 9 Pro recorded the run as 42.76km (26.5 miles), while the Apple Watch Ultra 4 recorded 43.33km (26.9 miles). The difference in distance was about half a kilometer, favoring the Garmin Fenix 9 Pro.

When it came to pacing, my bib recorded an average pace of 4:52 min/km, while the Garmin Fenix 9 Pro recorded 4:48 km, and the Apple Watch Ultra 4 registered 4:44 km. The Apple Watch Ultra 4 recorded a higher average heart rate of 172 beats per minute, compared to the Garmin Fenix 9 Pro's 179 beats per minute. However, I wore an Oura Ring 5 during the race, which measured my average heart rate as 179 beats per minute, confirming the Garmin's accuracy.