I raced a half marathon with the Apple Watch Ultra 2 vs. Garmin Forerunner 965 — here’s the winner

Garmin Forerunner 965 and Apple Watch Ultra 2 compared in a half marathon
(Image credit: Tom's Guide)

The Garmin Forerunner 965 and Apple Watch Ultra 2 are two of the best sports watches I have tested in the last couple of years, and as a keen runner both are laden with features that help me during training and on race day.

To test out their accuracy and usefulness for racing, I wore both to run the Battersea Park half marathon in London last weekend, where I clocked a PR of 1:09.46. I checked the GPS tracks of both watches after the race, as well as comparing their distance to the mile markers on the course during the event.

I also wore a Polar Verity Sense armband heart rate monitor, which I’ve found to be reliably accurate during my testing, so I could check the HR readings of the Apple Watch Ultra 2 and Garmin Forerunner 965. The Verity Sense was connected to a Coros Pace 3 watch that I had in my pocket, just to make it easier to get the HR data after the race for comparisons.

GPS Accuracy

Garmin Forerunner 965 and Apple Watch Ultra 2 compared in a half marathon

(Image credit: Tom's Guide)

The race involved running eight and three-quarter laps around the bottom half of a park. It was a crowded event which meant I had to run wide on every loop aside from the first one, and looped courses like this are always a challenge for GPS accuracy in my experience.

Both the Garmin Forerunner 965 and Apple Watch Ultra 2 ended up tracking longer than the official half marathon distance of 21.1km (13.11 miles), with the Apple Watch clocking 21.50km (13.35 miles) and the Garmin 21.23km (13.19 miles). I almost certainly ran further than the official distance given I had to weave around people and run wide on corners, but even so the Apple Watch’s reading seems a bit high to me.

Blue - Apple Watch Ultra 2 Brown - Garmin Forerunner 965

GPS trace: Blue — Apple Watch Ultra 2, Brown — Garmin Forerunner 965 (Image credit: DC Rainmaker Analyzer)

Looking at the GPS trace of the event you can see the loops recorded show the Apple Watch taking wider turns on most corners than the Garmin, adding the extra distance. On some turns I’d say the Apple Watch looks better than the Garmin, judging by my memory of the way I ran the race, but on some it looks like it's giving me some extra distance.

Overall the Forerunner 965’s distance was a lot closer to the race distance on an officially measured course, and even with the fact I had to run wide a lot of the time, I think the Garmin was a little more accurate on this front.

HR Accuracy

Garmin Forerunner 965 and Apple Watch Ultra 2 compared in a half marathon

(Image credit: Tom's Guide)

The Apple Watch Ultra 2 had a bad day on the heart rate front, consistently reading much higher than the Polar armband, and also dropping out entirely for some stretches. In contrast the Garmin Forerunner 965’s readings lined up closely with the armband’s for the whole race, with my heart rate rising steadily as I got more and more tired.

Blue - Apple Watch Ultra 2 Brown - Garmin Forerunner 965 Purple - Polar Verity Sense

Heart rate: Blue — Apple Watch Ultra 2, Brown — Garmin Forerunner 965, Purple — Polar Verity Sense (Image credit: DC Rainmaker Analyzer)

As a result the Garmin’s average and max heart rate readings were a lot closer to the Polar Verity Sense’s, and if I was using HR to judge my effort in the race it would have been a lot more useful than the Apple Watch Ultra 2.

That said, outside of this race, I’d say the Apple Watch Ultra 2 is usually OK for heart rate, and recently produced an accurate graph for me during a 10K race.

Pacing

Garmin Forerunner 965 and Apple Watch Ultra 2 compared in a half marathon

(Image credit: Tom's Guide)

For this race I used the pacer mode on the Apple Watch Ultra 2, where you set a target pace or time goal and it then shows how far ahead or behind that goal you are throughout the race. On the Garmin Forerunner 965 I used lap pace and manually took a lap each time I went through the timing mats that marked the start/end of each lap of the park, which was roughly every 2.4km (1.5 miles).

The Apple Watch pacer mode is great and I’ve used it in the past when running a marathon when it was pretty much spot on and helped me hit my target. However, because the distance tracked by the watch ended up higher than the half marathon distance, it was generous throughout the race in saying how far ahead of my target I was.

I had to ignore the pacer mode in the main and instead use the Forerunner 965’s manual lap splits and check my overall time against the mile markers on the course — luckily the math for my goal of sub-1:10 is easy because it’s 5:20 per mile. Though the Forerunner 965 also ended up recording a longer distance, I was able to judge my pace using it on each lap and it was more useful than the Apple Watch Ultra 2 in this event.

Verdict

There was a clear winner for this race, with the Garmin Forerunner 965 being more accurate on heart rate and more useful on pacing because it had an overall distance closer to the official half marathon distance.

The Apple Watch Ultra 2 still was pretty good on distance given I did have to run wide, but the heart rate accuracy was off and the normally great pacer mode wouldn’t have helped me hit my goal if I’d relied on it entirely.

More from Tom's Guide

Nick Harris-Fry
Senior Writer

Nick Harris-Fry is an experienced health and fitness journalist, writing professionally since 2012. He spent nine years working on the Coach magazine and website before moving to the fitness team at Tom’s Guide in 2024. Nick is a keen runner and also the founder of YouTube channel The Run Testers, which specialises in reviewing running shoes, watches, headphones and other gear.

Nick ran his first marathon in 2016 after six weeks of training for a magazine feature and subsequently became obsessed with the sport. He now has PBs of 2hr 27min for the marathon and 15min 30sec for 5K, and has run 13 marathons in total, as well as a 50-mile ultramarathon. Nick is also a qualified Run Leader in the UK.

Nick is an established expert in the health and fitness area and along with writing for many publications, including Live Science, Expert Reviews, Wareable, Coach and Get Sweat Go, he has been quoted on The Guardian and The Independent.

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  • Mos Chops
    Wow, that heart rate from the Apple watch is hot garbage. Now my FR 255 once in over 6 months of use gave me a consistently low reading until I tightened that strap down - but I've never seen it reading massively high like that. It would trigger an incident warning if it did so glad it doesn't.

    Anyway on the pacing front why don't you use the Garmin PacePro feature? I have mine speak the current pace and average pace every half mile and every quarter mile it does a check in and tells me if I'm ahead or behind of my plan. Plus you can have it use a linear increasing or decreasing pace across the race to meet the time you want, and you can even have it adjust pace up or down for hills. Very flexible.
    Reply
  • Nick HF
    Hey! The HR was poor that day for sure, has been better in the past but I suspect it locked on to my cadence rather than heart beat for most of the race. On PacePro, I've used it in the past but find it useful mainly for hilly races, because you can adjust the pace to account for ups and downs like you mention. On a flat course like his I knew the pace I needed and it didn't vary, so just checking lap pace occasionally throughout the 2.4km lap was fine.
    Reply