The Apple Watch Ultra 3 vs. Garmin Fenix 8: Which Adventure Watch Wins in 2026?

I’m not a professional adventurer. I’m a guy who likes to go backpacking every few months, run a 10K on weekends, and occasionally pretend I’m an athlete. For years, I’ve worn a Garmin Fenix because it felt like the serious choice—the one that wouldn’t let me down in the backcountry. But when the Apple Watch Ultra 3 dropped last month, with its new satellite SOS feature and improved battery life, I wondered: has Apple finally caught up? To find out, I spent a week hiking the Colorado Trail with both watches strapped to my wrists. Here’s who won.

Battery Life: The King Still Rules

Let’s get the big one out of the way. The Garmin Fenix 8 lasts up to 28 days in smartwatch mode and up to 65 hours in GPS mode. The Apple Watch Ultra 3 is rated for 36 hours in normal use and about 18 hours with GPS. On a multi-day hike, that difference is everything. On day three of my trip, the Apple Watch died during a nine-mile stretch with heavy navigation. The Garmin still had 40% battery. I had to rely on my phone for the rest of the day, which felt like a failure. If you’re doing a long trek without access to power, the Fenix is the clear winner. Period.

But here’s the nuance: the Apple Watch charges faster. I can get it to 80% in about 45 minutes with a USB-C plug. On a trip where I’m staying at a hut with power, that’s fine. The Garmin takes over two hours to fully charge. So if your trips are short (under 36 hours) or you have access to outlets, the battery gap narrows. For me, though, the peace of mind of the Fenix’s longevity is worth the slower charging.

Navigation: Garmin’s Secret Weapon

I loaded both watches with a GPX route for a 12-mile loop through the Indian Peaks Wilderness. The Garmin Fenix 8 handled it like a pro. The maps are crisp, the turn-by-turn directions are clear, and the screen is always on. The Apple Watch Ultra 3 struggled. Its mapping interface is cleaner and prettier, but it requires a tap to wake the screen, which is annoying when you’re scrambling over rocks and your hands are full. The Ultra 3 also drains battery faster when using GPS, as I mentioned. On a technical trail, the Garmin’s dedicated hardware buttons are a godsend. You can press them with gloves or in rain. The Apple Watch’s touchscreen is useless when wet.

That said, the Ultra 3’s Compass app is surprisingly good. It shows elevation, coordinates, and waypoints in a clean interface. For a day hike, it’s fine. For serious backcountry navigation, the Fenix wins.

Health and Fitness Tracking: Apple Closes the Gap

This is where the Ultra 3 shines. Its heart rate sensor is more accurate than the Fenix 8’s, especially during high-intensity intervals. I ran a mile at a brisk pace, and the Apple Watch recorded an average HR of 162, while the Garmin said 155. I trust the Apple Watch because I checked with a chest strap later. The Ultra 3 also has a better sleep tracker. It detected my REM cycles and gave me a sleep score that felt accurate. The Garmin’s sleep tracking is okay but often thinks I’m awake when I’m just lying still.

The Ultra 3 also has a new “Vitals” app that shows trends over weeks, like your resting heart rate and respiratory rate. It’s genuinely useful. The Fenix 8 has similar features, but the presentation is clunkier. Apple’s UI is just more intuitive. For daily fitness tracking, I’d pick the Ultra 3. For ultrarunning or triathlon training, the Fenix’s advanced metrics (like training load and recovery time) are more detailed.

Durability and Design: A Tie, but Different

Both watches are built like tanks. The Ultra 3 has a titanium case and a sapphire crystal display. The Fenix 8 has a titanium case with a sapphire lens and a polymer back. Both are water-resistant to 100 meters. I scraped the Apple Watch against a granite boulder, and it didn’t scratch. The Garmin has a slightly thicker bezel that protects the screen better. I’d trust both in a fall. The Ultra 3 is lighter (61g vs. 88g for the Fenix 8), which makes it more comfortable for sleeping. The Fenix 8 feels like a brick on my wrist, but I got used to it.

The Ultra 3’s new “Action Button” is customizable and useful—I set mine to start a hiking workout. The Fenix 8 has five hardware buttons, which is overkill but gives you more control. Design preference is subjective, but I think the Apple Watch looks sleeker. The Fenix 8 looks like a tool. Both are good, but different.

Price: A Honest Comparison

The Apple Watch Ultra 3 starts at $899. The Garmin Fenix 8 starts at $1,199 for the 47mm version. That’s a $300 difference. For most people, that’s significant. The Ultra 3 offers better value for daily use: it’s a great smartwatch that also handles adventures. The Fenix 8 is a premium tool for serious athletes and explorers. If you only hike a few times a year, save the money and get the Ultra 3. If you’re planning a thru-hike or a multi-day expedition, the Fenix 8 is worth the premium.

I’m keeping the Garmin. But I’ll admit that I missed the Ultra 3’s smartwatch features—responding to texts, controlling my music, and using Apple Pay. The Fenix 8 can do some of that, but it’s not as seamless. If this were my only watch, I’d probably choose the Apple Watch. But for the trips I do, the Garmin is the tool I trust. That’s a frustrating but honest conclusion.