Club Benefits
The Apple Watch Ultra 3 and Garmin Forerunner 970 are two of the best sports watches available, and two of my favorites to wear as a marathoner. I rate the Forerunner 970 as the best running watch money can buy, while the Apple Watch Ultra 3 is the best sporty smartwatch.
I wore both watches to run the Surrey Half Marathon at the weekend, testing their GPS against each other and their heart rate tracking against a chest strap, which I paired to a Coros Pace 4 watch in my pocket.
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GPS Accuracy
The Surrey Half Marathon mostly takes place on country roads, with the start and finish in the town of Woking. It’s a pretty easy course for GPS accuracy as a result, with no tall buildings and minimal tree cover to stymie satellite signals.
Both watches were close to the official half marathon distance of 13.1 miles, with the Garmin clocking 13.15 miles and the Apple Watch 13.22 miles, so the Forerunner 970 was a little closer to the right distance.
During the race, I was rarely in a big crowd of runners, so I was able to take the most direct racing line throughout and probably only ran a little over the official distance. I think both watches were in the right ballpark.
I also looked at the GPS tracks from the race afterward, and they matched very closely throughout, to the point where I’m not sure how they ended up with even a 0.07-mile disparity. Both are reliable GPS watches for sure.
HR Accuracy
The optical sensors on watches aren't as reliable as a chest strap sensor, which measures electrical signals directly from the heart. I compared the Garmin and Apple readings with the Garmin HRM 600 chest strap for average and maximum heart rate.
| Row 0 - Cell 0 | Garmin HRM 600 | Garmin Forerunner 970 | Apple Watch Ultra 3 |
Average Heart Rate | 158 | 156 | 172 |
Max Heart Rate | 174 | 172 | 203 |
Unlike with the GPS accuracy, there was a big difference in the accuracy here, with the Apple Watch Ultra 3 often reading far too high a heart rate, as well as frequently being unable to read my heart rate at all.
Meanwhile, the Forerunner 970 was very close to the reading from the chest strap throughout. It took longer to reach the correct heart rate at the start of the race and had a couple of erroneous dips, but overall, its accuracy was impressive.
Design
This is a small point, but I did notice the extra size and weight of the Apple Watch Ultra 3 compared with the lightweight, slim Forerunner 970. As someone with thin wrists, I prefer the feel of the Garmin on my wrist.
That said, the Apple Watch Ultra 3 has a more premium design and should be more durable thanks to the titanium case.
Verdict
On this occasion, the Garmin Forerunner 970 proved to be the more reliable running watch, with slightly better GPS accuracy and considerably better heart rate accuracy than the Apple Watch Ultra 3. The Forerunner 970 is my go-to watch, so it’s great to see it prove so reliable on race day.
However, I have run many races with both watches and each has proved very reliable for the most part — the Apple Watch Ultra 3 was very good for a marathon test last year, for example — so you can shop either watch with confidence you’re getting a strong option for running.
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