I ran a marathon with the Apple Watch Ultra 4 and Coros Pace Pro 4 to test their accuracy and battery life — here’s the winner

The Coros Pace 4 Pro and Apple Watch Ultra 4 both launched in September this year and both impressed me in my testing overall. I rate the Coros as one of the best sports watches available, while the Apple Watch Ultra 4 is my favorite sporty smartwatch.

I wore both for my final week of training for the Frankfurt Marathon, and then for race day itself, where I ran 2:25 in my 18th marathon.

With one watch on either wrist, I was keen to see if there were any noticeable differences in their GPS and heart rate accuracy on the day.

I also checked their battery life throughout the weekend to see how fast they were draining, noted any design differences that stood out, and kept in mind how useful they were outside the run itself.

This was a true sports watch vs. smartwatch test, and I’ve picked out the key differences I noticed between the two watches over the marathon weekend below. For more detailed info on either watch, check out our full Apple Watch Ultra 4 review and Coros Pace 4 Pro review.

Apple Watch Ultra 4 vs Coros Pace 4 Pro: Price

Before diving into the test, it’s worth noting that the Coros Pace 4 Pro is cheaper than the Apple Watch Ultra 4. It will set you back $449, compared with $799 for the Apple.

Coros rarely reduces its watches, whereas the Ultra 4 is likely to go on sale in time, which will make the gap between them smaller, but the Pace 4 Pro is always going to be the more affordable pick.

Apple Watch Ultra 4 vs Coros Pace 4 Pro: Design

I love the look of both watches, but they have a different feel on the wrist. The Apple Watch Ultra 4 has a full titanium case and is more robust and heavy — it’s a more premium look for sure.

The Coros Pace 4 Pro is delightfully light and slim, and has a sapphire crystal case and a titanium bezel, so it’s also going to be durable.

Both watches have three buttons, one of which is a dial, and bright displays that are easy to read in all conditions, including the wet and windy day we had in Frankfurt.

In the rain, the fact that you have to use the touchscreen on the Ultra 4 to navigate its apps and menus is a little annoying compared to the buttons on the Coros.

Importantly, you can do all the key actions you need during runs, like pause and lap, using buttons on the Apple Watch Ultra 4, but you have to use the screen to actually end your run.

Apple Watch Ultra 4 vs Coros Pace 4 Pro: GPS accuracy

The Frankfurt Marathon is a tough test for GPS accuracy because the first and final 5K of the race involve twisting around the skyscrapers in the city center. In between, it’s easy enough for watches, with a big loop out to the suburbs.

On the day, the Coros Pace 4 Pro logged a total distance of 42.52km (26.42 miles) and the Apple Watch Ultra 4 logged 43.07km (26.76 miles).

The official marathon distance is 42.19km/ 26.21 miles, and although you never run exactly this distance in an event because of weaving around crowds, I certainly think the Coros Pace 4 Pro was more accurate.

I noticed it was closer in line with the kilometer markers on the course, and because I was in the first 100 runners, I was able to stay pretty close to the most direct racing line throughout the event, so the Ultra 4’s total distance seems too much (it also read long for my colleague Jane at the event).

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Looking at the GPS tracks of the watches, you can see they both went wrong at various stages in the city center under the tall buildings there, but the Ultra 4 cut corners and tracked me off the road more often.

This was unexpected for me, as I’ve run marathons with every Apple Watch Ultra and generally they have been pretty good on GPS accuracy in city centers.

I actually used the pacer mode on the Apple Watch Ultra 4, and it logged me finishing the marathon in 2:23… if only.

Apple Watch Ultra 4 vs Coros Pace 4 Pro: Heart rate accuracy

Concerning heart rate accuracy, I’m not going to be too hard on either watch because I didn’t wear a chest strap to get a reading to compare them to, and I wore arm sleeves during the marathon, which had watch holes but might have impacted the sensor accuracy.

Looking at the graph of the readings from the two watches, I’d say two things stood out to me when comparing them with past marathons and what I know my heart rate tends to do during them.

One is that the Coros had a consistent reading, but it looks too high compared with my max heart rate of around 176, and it doesn’t trend up throughout the event, which always happens during marathons in my experience.

The Apple Watch Ultra 4’s readings look more accurate to me, aside from the long section from the one-hour to two-hour mark where it didn’t take a reading, greying out the number on the watch because it wasn’t confident it had it right.

I’ve done a lot of testing of the heart rate sensors on both watches outside the marathon (when not wearing arm sleeves), and both are pretty good, but if you want the most reliable results, I’d always say using a chest strap is better.

Apple Watch Ultra 4 vs Coros Pace 4 Pro: Battery life

The Coros Pace 4 Pro certainly wins the battery life battle between these watches, lasting up to seven days on a charge with the screen always-on, compared with 50 hours on the Apple Watch Ultra 4.

I used the marathon weekend away as a chance to test the real-world battery life performance of the two, taking both off the charger early Friday morning when I flew to Frankfurt.

After short runs with both watches on Friday and Saturday, the Coros was down to 75% on Sunday morning, and the Apple Watch Ultra 4 was at 41% (note that I didn’t sleep with them on, so that saved some battery life).

At that point, I got nervous about the Ultra 4 lasting the marathon and charged it to 75% to match the Coros, which didn’t take long thanks to the fast charging on the Apple.

During the race, I did listen to music on the Apple Watch Ultra 4 for about an hour, which increased how much battery it used, but even so, I could have got by with the 41% it originally had left, as it only drained by 16% in the race.

The Coros only lost 10% of its battery in the race, though, and is certainly the better option for battery life, but the Ultra 4 did impress me over the course of the weekend, and still had 32% of its battery left when I got home on Monday, with only that one short charge over the whole marathon weekend.

Apple Watch Ultra 4 vs Coros Pace 4 Pro: Smart features

The Apple Watch Ultra 4 is clearly a better smartwatch than the Coros, with a full App Store, easy music storage through streaming services and NFC payments. The Coros can store MP3 files for Bluetooth playback, but that’s about it.

This did come across on a weekend away, where the Ultra 4 could do things like show boarding passes for my flights, and I could wirelessly adjust my running playlist on the watch pre-race and listen to music during the event.

The Apple Watch Ultra 4 also has more customization options, especially on watch faces. If it’s smarts you want, it’s definitely the better pick.

Apple Watch Ultra 4 vs Coros Pace 4 Pro: Specs

Apple Watch Ultra 4 vs Coros Pace 4 Pro: Verdict

The weekend trip showcased the pros and cons of both sports watches and smartwatches, and there still isn’t one device from any brand that manages to nail both sides of the coin.

During the marathon, the Coros Pace 4 Pro was more reliable for GPS accuracy and pacing, which is absolutely crucial for me, and it offers much better battery life than the Ultra 4.

However, the Apple Watch Ultra 4 is certainly a more useful smartwatch, and it does still offer good sports tracking and a very attractive, robust design.

As someone who has made running most of my job and personality, the superior sports tracking of the Coros Pace 4 Pro is what I’d go for, and I love its lighter design too, but the Apple Watch Ultra 4 is a well-rounded pick that handles sports and smarts better than most.

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