I've been wearing the OnePlus Watch 3 for the past couple of months, and I have to say — this thing is a battery beast. Five days on a single charge with an AMOLED display? That's basically unheard of in the Wear OS world. Let me break down everything you need to know.
The Big Story: Battery Life That Actually Delivers
Here's the deal: the OnePlus Watch 3 runs not one but two operating systems simultaneously. There's Wear OS 5 for the full smartwatch experience, and then a low-power RTOS running in the background for basic functions. When you're not actively using apps, it switches to RTOS and sips power instead of guzzling it.
The result? Up to 5 days of battery life in smartwatch mode, and up to 16 days in power saver mode. I've been testing it with daily workouts and always-on display, and I'm getting about 4.5 days — which is still incredible for a Wear OS watch.
"The OnePlus Watch 3 is one of the best looking smartwatches I own." — Rob ter Horst, Quantified Scientist
This isn't some theoretical battery life either. This is real-world usage. Notifications, always-on display, GPS workouts, sleep tracking — everything enabled. And it still lasts a full work week. Compare that to the Pixel Watch 3 (maybe 1.5 days) or Galaxy Watch 7 (similar), and you start to understand why this is such a big deal.
Design: Big, Beautiful, and Premium
Let's not beat around the bush — this is a big watch. At 46.6mm, it's not for small wrists. But what you get for that size is gorgeous.
The 1.5-inch LTPO AMOLED display boasts 466x466 resolution and up to 2,200 nits of peak brightness. That's as bright as the Apple Watch Ultra 2. I had zero issues seeing this watch in direct sunlight — it's genuinely impressive.
The titanium bezel and stainless steel case give it a premium feel that rivals watches costing twice as much. After 100 days of use, Matt LeGrand noted in his long-term review that he couldn't find visible scratches even under macro lens inspection. That's thanks to the sapphire crystal glass.
The new rotating digital crown makes navigation so much easier than touchscreen alone — especially during workouts when your fingers are sweaty. You can scroll through notifications, access quick settings, and navigate menus without smearing the display.
The Dual-Engine Architecture
This is the secret sauce. Most Wear OS watches run a single OS and drain battery quickly. OnePlus figured out that you don't need full Wear OS running when you're just checking time or tracking steps.
The dual-architecture works like this:
- Wear OS 5 handles apps, Google services, and full functionality
- RTOS (real-time operating system) handles basic functions when the screen is off
When you raise your wrist, it seamlessly switches to Wear OS. When you lower it, it goes back to RTOS. You barely notice the transition, but your battery definitely notices the savings.
Health Features: Finally Getting Serious
OnePlus added meaningful health upgrades this generation:
- Wrist temperature sensor — tracks skin temp overnight
- Improved heart rate sensor — Gen 5 optical HR
- ECG functionality — available in some regions (FDA pending in US)
- 60-second health check-in — measures heart rate, SpO2, mental wellness, wrist temperature, sleep quality, and vascular age
The vascular age feature is fascinating — it compares your cardiovascular health to your actual age. In my testing, it was consistently generous (I'm apparently years younger than my birth certificate says). Whether that's accurate or optimistic is debatable, but it's a unique data point.
The 60-second health check-in is quick and convenient. It gives you a snapshot of your current health status without needing a full workout session. Great for morning check-ins or before/after flights.
GPS and Workout Tracking
The dual-frequency GPS (L1 + L5) is accurate for running and cycling. I took it on several runs comparing it side-by-side with my Garmin, and the routes matched up closely — within a few meters typically.
There's support for 100+ sports modes, but only 11 offer "professional modes" with detailed metrics. For casual fitness enthusiasts, that's plenty. Triathletes will want to look elsewhere — the swim tracking had issues with stroke detection in my testing.
The workout app is clean and easy to use. Starting a run is one button press, and the display shows all the metrics you'd want: pace, distance, heart rate, splits, and more.
Software: ColorOS Meets Wear OS
This is where things get complicated. The OnePlus Watch 3 runs both ColorOS (for OnePlus-specific features) AND Wear OS 5. The result is... mixed.
On the positive side:
- Smooth performance thanks to the Snapdragon W5 Gen 1 chip
- Quick pairing with Android phones
- Nice companion app with detailed stats
On the negative side:
- Some redundancy between ColorOS and Wear OS features
- Not all OnePlus features work with iPhones
- The software experience isn't as polished as Pixel or Galaxy
For Android users, this is probably fine. For iPhone users, I'd think twice — you might lose some functionality.
The Not-So-Great
No watch is perfect, and the OnePlus Watch 3 has some drawbacks:
- It's huge — definitely try it on in person before buying
- Sleep tracking interpretation can be questionable (one night it said I had low deep sleep when I actually slept 8+ hours)
- Swim tracking has issues with stroke detection
- No LTE option yet
- ECG still not FDA cleared in the US despite having the hardware
The size is the big one. This is a chunky watch. If you have smaller wrists or prefer something more subtle, look elsewhere. The 43mm version helps somewhat but still isn't small.
Battery Charging
The magnetic charging puck is convenient. Zero to 100% takes about 90 minutes. You get a few hours of use from a 15-minute charge, which is handy for travelers.
OnePlus claims the watch can last up to 16 days in Power Saver Mode, which disables most smart features. That's essentially become my travel mode — when I'm going off the grid, I switch to Power Saver and don't worry about charging for two weeks.
The Verdict
The OnePlus Watch 3 isn't perfect, but it's easily one of the best Wear OS watches you can buy right now — especially if battery life is your top priority.
Best for: Android users who want the best battery life without sacrificing smartwatch features. If you're tired of charging your watch every day or two, this is the answer.
Look elsewhere if: You have small wrists, need LTE, want the absolute best fitness tracking accuracy (Pixel Watch 3 beats it there), or are heavily invested in the Apple ecosystem.
At $329 for the 47mm version, you're getting premium build quality, excellent display, and battery life that competitors can't match. It's not cheap, but it's priced competitively against the Pixel Watch 3 and Galaxy Watch 7.
What do you think — is 5 days of battery worth the chunky size? Drop your thoughts below!