I have tested COROS VERTIX 2 and VERTIX 2S over the last four years, and they have been my favorite training partners in daily life. I love being on the COROS bandwagon; I like the simple and clear ecosystem, there are enough features for any runner, there's always an update around the corner, and I'm obsessed with the battery life.
Now is here – the ultimate watch for mountaineering – and I've tested it for almost four months. Here are my thoughts. Spoiler alert: I'm so in love with it that I've stopped using all other watches.
If you want an overview of all COROS watches, you can look at the table below.
New features – COROS APEX 4
Compared to VERTIX 2S, COROS APEX 4 has gained almost every feature, except for the larger physical size, build quality for everyday Everest trips, and the extreme, almost unnatural battery life. In many cases, I would actually categorize Coros Apex 4 as the new top watch, simply because of the new updates it has received – and because VERTIX 2S is made for the few, extreme athletes who climb 8000-meter high mountains or run the longest ultramarathons, I would say that COROS APEX 4 is also more "popular."
Here is the list of the most important updates that set it apart from previous models:
- A new speaker and microphone for calls and voice messages.
- A new processor drastically increases performance.
- A brand new MIP screen (Memory In Pixel) with higher contrast.
- A new action button.
- And it may seem trivial, but it's not: new charging accessories.
COROS is very precise in their target group with APEX 4. The entry model, COROS PACE 4, which my colleague Jeppe has tested, actually has too many features to be an "entry-level" watch. It has more features than the average runner or triathlete will ever need. The upgrade to a COROS APEX 4 is therefore for those who need long battery life, a more robust construction that stays nice longer, ECG sensor, navigation, speaker, climbing accessories, and specific features for all the fun you can have on the mountain.
Strongly built, yet compact - COROS APEX 4
Let's talk about the construction first. COROS APEX 4 comes in two sizes: 42mm and 46mm. It's smaller than the massive 52mm VERTIX 2S, which I actually think is okay. APEX 4 has a titanium bezel (not the entire watch like VERTIX 2S), sapphire glass, and reinforced strap pins to be as light and strong as possible. It has an ECG sensor for heart health monitoring, a quick-release strap, and comes with a silicone strap (a nylon strap is on the way for those who prefer it, like I do).
Weight-wise, APEX 4 is positioned right between PACE 4 and VERTIX 2S. It's noticeably lighter than my previous watches, which I'm excited about. And despite the smaller size, the battery performs exactly as a Coros watch should – which means phenomenally. But more on that later.
Easy setup - COROS APEX 4
When you get the watch, the setup couldn't be simpler. You download the COROS app, create a user, scan the QR code on the device, answer a few questions, and in a few seconds, you and the watch are ready for the run.
Your data is found in the app, where you can view statistics, create routes, find workouts, track your gear, download free topographic maps worldwide, find new watch faces, and update firmware. If you want even more control and training metrics, you can log into Evolab on your computer to dive deeper into your running data. For most runners, however, the app can do everything you need without feeling overwhelming.
Battery life as only COROS can do it
After two months of testing, I've enjoyed a battery life of about 3 weeks per charge (with 2-3 activities a week). It will likely be between 2 and 3 weeks when I ramp up to 5-7 activities a week. This battery life is measured with the GPS set to "MAX" (dual frequency). Although APEX 4 may not match the battery of VERTIX 2S, it's not too shabby!"
COROS, however, has two other levels: HIGH (all 5 systems on) and ENDURANCE (lowest power consumption, but still all GPS systems active). Compared to the MAX setting, ENDURANCE can increase GPS battery life by 50-60%. COROS itself says APEX 4 has 24 days of battery life in smart watch mode.
I've found that in my area, I only need Endurance mode. I've logged runs of two hours, where the watch only used about 7% power throughout a whole day (here the GPS uses about 43% of the 7%)! The tracking is still spot on the road and is measured with such high frequency that the route never 'lags' on the map afterward. So if you train with GPS for an average of two hours a day, you can expect the Coros Apex 4 to last up to two weeks between charges (though without music).
If you run in cities with tall buildings or in dense forests and deep valleys, the MAX setting may be necessary. It uses dual-frequency to eliminate reflected signals, which requires more power but provides higher precision under difficult conditions. But in open landscapes, ENDURANCE does a fantastic job; on a full charge, it gives you up to 65 hours of GPS time – enough for Tom Evans to complete Ultra Trail Mount Blanc three times.
A new screen - COROS APEX 4
The big difference between APEX 4 and both VERTIX 2S and PACE 4 is the screen. The screen on APEX 4 doesn't have the same high resolution and bright color as the smaller COROS PACE 4, but there's a good reason for that. COROS APEX 4 focuses on long battery life, and the MIP (Memory in pixel) screen is in a class of its own. It provides up to 24 days of battery life with the "always-on" display turned on. That's four times as much as PACE 4 with the same setting.
Compared to VERTIX 2S, which has a similar screen type, APEX 4 excels. It has more contrast, is extremely sharp in daylight, and the backlight makes it comfortable to look at in the dark. I don't need an AMOLED screen; for me, battery life is more important, and the new MIP screen is more than good enough.
If you want to make the screen even clearer, you can advantageously switch to a watch face with a white background and black text, as it significantly increases readability.
New lightning-fast processor – COROS APEX 4
The feature that has the greatest impact in daily life is the new processor, which is said to be up to 30 times faster than in previous models. This is clearly felt in everyday use and especially when using maps and navigation. Everything feels smooth, and I also suspect the increased computing power improves the accuracy of both the heart rate monitor and GPS.
I therefore tested the GPS against other top models while cross-country skiing in the Norwegian mountains, and COROS APEX 4 was extremely accurate in MAX mode. It's impressive that they have achieved such a big leap in performance without compromising battery life.
The touch function on the screen also comes into its own thanks to the fast processor. It now feels so smooth and natural that I often find myself using the screen for navigation instead of the buttons, something that has never been the case before.
Run and talk - COROS APEX 4
COROS has now implemented both a microphone and speakers in APEX 4, making it possible to make calls directly from the watch. At first, I thought it was a niche thing, but when you need it, it's brilliant. As a father of three, I rarely have both hands free, and my phone tends to disappear (here the "find my phone" function is a lifesaver).
Sound quality during calls naturally depends on wind and pace, but at a normal walking pace, the sound is so good that my wife was surprised I was talking to her through the watch. I also use the microphone to record short notes after training. The app's AI transcription has worked flawlessly even with my Norwegian dialect.
A new button with potential - COROS APEX 4
APEX 4 has received a new third button. Right now, it functions as a programmable shortcut during activities, which can be tailored to your needs. It can either be set up as a traditional lap button, used to quickly record a 'voice pin,' or function as a quick button that switches between maps, music, and training screens.
Although I love that COROS keeps their operating system both on the app and watch simple, I'm excited to see what they come up with for this button in the future – maybe quick access to settings or the week's planned workouts?
There is still room for improvement before you get the full benefit of the new button. For example, I rarely listen to music when I run, so for me, it's unnecessary for the music screen to be part of the rotation, something it is sometimes even when I'm not using the phone. It would be obvious if you could deselect the screens you don't use, so it just switches directly between map and activity screen. I have many ideas, so if you want to know them COROS, get in touch!
Charging on the go - COROS APEX 4
The last novelty is a small, portable mini-charger that you can have on your keychain. It sounds trivial, but it's incredibly practical. Most households have a USB charger lying around, and with this new mini-charger, you can easily get power to the watch, no matter where you are. Both Jeppe and I have become very fond of the detail. Because the watch holds power for so long, you often forget where you put the normal charging cable. With this little thing, you always have power at hand, as long as you can get hold of a USB-C charging cable, and you can almost always do that.
Conclusion
COROS APEX 4 is a fantastic watch for those who want advanced features and a battery life you don't have to worry about. Especially when you also get the fantastic ecosystem COROS has built over the years. COROS continues to update their watches – even older models – so when you buy an APEX 4, you're getting a product that improves over time. And all updates are so well thought out that they almost always work optimally right away.
For example, COROS released seven major updates to the watch and apps in 2025, and they have already started strong in January 2026.
If you want a lighter watch or a more beautiful AMOLED screen, PACE 4 or PACE Pro are good alternatives. But if you want a rock-solid watch with precise sensors that lasts forever on a charge and is made for wild adventures in the mountains, then COROS APEX 4 is the perfect choice.
If you want more information about COROS, you can read our overview of all COROS watches.
