Buying a smartwatch sounds easy until you have to choose between two great options like the Xiaomi Watch S5 vs OnePlus Watch 3. On paper, both offer AMOLED displays, health tracking, built-in GPS, long battery life and premium designs. But after using both in my daily routine, I realized they deliver very different experiences.
I wore both watches during work, workouts, outdoor walks and even while sleeping to see how they performed beyond their spec sheets. A good smartwatch should feel comfortable, track your health accurately and last long enough that charging doesn’t become a daily task.
While both smartwatches have plenty to offer, the differences become much more noticeable in everyday use. From display quality and fitness tracking to battery life and software experience, here’s how the Xiaomi Watch S5 vs OnePlus Watch 3 compares.
Xiaomi Watch S5 vs OnePlus Watch 3: Quick Comparison
| Feature | Xiaomi Watch S5 | OnePlus Watch 3 |
|---|---|---|
| Display | 1.48-inch AMOLED, 2500 nits peak, 480×480 px | 1.5-inch LTPO AMOLED, 2200 nits peak, 466×466 px |
| Operating System | Xiaomi HyperOS 3 | Wear OS 5.0 + ColorOS Watch 7.0 |
| Processor | Proprietary Surge Architecture | Snapdragon W5 Gen 1 + BES2700 Dual-Engine |
| Battery Life | 9 days (AOD) to 14 days (Normal usage) | Up to 5 days (Smart Mode with Dual-Engine) |
| Battery Capacity | 815mAh | 648mAh |
| Materials | 316L Stainless Steel frame, interchangeable bezels | Stainless steel frame, Sapphire Crystal front glass |
| Thickness & Weight | 10.99mm thickness, 46g (without strap) | 11.8mm thickness, 49.7g (without strap) |
| GPS Tracking | Dual-band, 5-system GNSS | Enhanced Dual-frequency GPS |
| App Ecosystem | Mi Fitness (Xiaomi Wear) | OHealth (OnePlus Health App) |
| Companion OS | Android 8.0+ and iOS 14.0+ | Android 8.0+ (No official iOS support) |
| Best For | Multi-week battery, style flexibility, iOS users | Deep app ecosystem, replying to texts, Google apps |
| Price | £149.99 GBP (approx $198.58 USD) | $349.99 |
Display & Design Comparison
When you first unbox these two, the design language immediately tells a story. I noticed right away how much thinner the Xiaomi feels on the wrist compared to its rival. Coming in at just 10.99mm thick and weighing 46 grams, the Xiaomi Watch S5 is incredibly sleek for a 46mm watch face. It is made from a highly polished 316L stainless steel frame that looks incredibly sharp in an office environment.
But what sets the Xiaomi apart is its structural customization. It features interchangeable physical bezels, allowing you to swap out the outer ring for options like Ceramic Blue or Forged Carbon depending on your style. The display itself is a magnificent 1.48-inch AMOLED panel boasting a crystal-clear 480×480 resolution. What blew me away during my outdoor tests was the brightness, it peaks at a massive 2,500 nits. When the sun is shining directly overhead during an afternoon run, the text stays perfectly sharp and legible.
On the other hand, the OnePlus Watch 3 is a bit more substantial on the wrist, measuring 11.8mm in thickness and weighing 49.7 grams. While it is slightly chunkier, it counters with superior physical durability. The front display panel is protected by genuine Sapphire Crystal glass, which has kept my unit completely scratch-free despite a few accidental scrapes against gym equipment.
It comes with a gorgeous 1.5-inch LTPO AMOLED display, which has a resolution of 466×466 pixels. Thanks to the LTPO technology, it dynamically drops its refresh rate when idling to save precious power. It peaks at 2,200 nits, which is slightly lower than the Xiaomi but still phenomenally bright for outdoor viewability.
When it comes to watch face customization, Xiaomi relies heavily on fun, interactive animated watch faces that respond when you tap them. It gives the device a friendly, approachable personality. OnePlus takes a cleaner, more minimalist executive route, focusing on dense, data-rich dials with clean layouts. For pure comfort during long 24-hour wear cycles, Xiaomi’s lighter and slimmer profile edges it out slightly, making it less noticeable when you are typing or sleeping.
Health & Fitness Tracking
If you are an active gym person or runner, the fitness tracking capabilities will make or break your decision. I have put both tracking suites through rigorous real-world tests to see how they handle heart rate spikes, sleep metrics and satellite routing accuracy.
Heart Rate & SpO2 Monitoring
For heart rate accuracy, Xiaomi upgraded its tracking array to a new four-light, four-photodiode layout. They claim a 98.4% accuracy rate and in my high-intensity interval training sessions, it held up remarkably well. It caught my rapid heart rate drops quickly without lagging behind the actual physical exertion. It tracks your blood oxygen levels continuously throughout the day, dropping alerts if your levels dip below normal parameters.
The OnePlus Watch 3 utilizes its dual-engine architecture to balance continuous health tracking. It keeps tabs on your heart rate and SpO2 without burning through your battery because its low-power coprocessor handles the baseline background monitoring. In my comparative tests, the heart rate readings between the two watches were consistently within 1 to 2 beats per minute of each other, proving that both brands have dialed in their modern sensor arrays beautifully.
Sleep & Recovery Tracking
Sleep tracking is an area where these two diverge quite a bit in presentation. Xiaomi developed its updated sleep algorithm 2.0 in close cooperation with professional institutions like the World Sleep Society. It boasts an 11% improvement in detecting exactly when you fall asleep and when you wake up. When analyzing my sleep data, it gives me a clear breakdown of light sleep, deep sleep and REM stages, along with breathing stability metrics.
The OnePlus Watch 3 relies on its comprehensive “60-second Health Check-In” feature. With a single touch, the watch checks your heart rate, blood oxygen, stress levels and skin temperature to provide a cohesive daily health assessment. It tracks your sleep stages flawlessly, but what I really love about the OnePlus ecosystem is how it combines your sleep data with your daytime stress metrics to give you practical recovery insights, showing whether your body is actually rested or still recovering from a demanding day.
Workout & Activity Tracking
When it comes to outdoor workouts, satellite positioning is everything. In this Xiaomi Watch S5 vs OnePlus Watch 3 showdown, both watches offer premium dual-frequency GPS setups. Xiaomi features an upgraded dual-band five-system GNSS chip that locks onto a satellite signal within seconds of stepping outside. It supports over 150 sports modes and includes an automatic workout detection feature that kicks in if you forget to manually start a walk or run.
OnePlus features its own Enhanced Dual-frequency GPS, which performs exceptionally well in dense urban environments or under heavy tree cover where lesser watches drop signals. The step counting on both devices is precise, though I noticed that Xiaomi’s software is slightly more aggressive at filtering out ghost steps caused by sitting at an office desk or typing.
Battery Life & Charging
The Xiaomi Watch S5 is powered by a massive 815mAh Xiaomi Surge Battery. Because HyperOS 3 is a lightweight, highly optimized proprietary operating system, its power draw is microscopic compared to Wear OS. In my regular testing cycle, with continuous heart rate tracking active, notifications buzzing throughout the day and a couple of tracked gym sessions, I easily achieved 14 days of battery life on a single charge.
Even if you turn on the Always-On Display, you can comfortably expect around 9 days of use. It completely frees you from the charging brick.
Whereas the OnePlus Watch 3 packs a 648mAh battery. Under normal circumstances, a full Google Wear OS watch would die after 2 days at best. However, OnePlus utilizes a brilliant Dual-Engine Architecture. It pairs a powerful Snapdragon W5 Gen 1 processor (which handles intensive tasks like Google Maps or replying to messages) with an energy-efficient BES2700 coprocessor (which handles the background tasks, clock face and sensor data). Thanks to this setup, the OnePlus Watch 3 delivers up to 5 days of battery life in full Smart Mode. For a full Wear OS watch, that is an incredible engineering feat, but it still falls short of the two-week freedom offered by Xiaomi.
When it comes to charging convenience, both use magnetic pucks. OnePlus takes advantage of its proprietary charging speeds, giving you a day’s worth of power in just about 10 to 15 minutes on the charger, while Xiaomi takes a bit longer to top off its massive 815mAh cell but only requires you to do so twice a month.
App Integration & Ecosystem
Xiaomi Wear
The Xiaomi Watch S5 syncs via the Mi Fitness app. The application layout is remarkably simple and easy to understand. The main dashboard gives you clean visual cards for your steps, sleep patterns and recent workouts. The data syncing is completely automatic and happens seamlessly over Bluetooth 5.4.
One massive advantage of the Xiaomi ecosystem is its platform flexibility. The Watch S5 supports both Android (8.0 and above) and iOS (14.0 and above). If you like to try different phones or use an iPhone for work and an Android device for personal use, the Xiaomi Watch S5 will work perfectly across both ecosystems without locking you out of features.
OnePlus Health
The OnePlus Watch 3 interfaces with the OHealth app. The app is beautifully designed, offering granular, deep clinical data analysis that tech writers and data nerds appreciate. It breaks down your historical fitness trends over weeks and months with high-precision charts.
However, there is a catch: the OnePlus Watch 3 is deeply integrated into the Android and OnePlus wearable ecosystem. Because it runs full Google Wear OS 5.0, it does not officially support iOS. If you own an iPhone, this watch is out of the question. But if you are an Android user, the ecosystem integration is elite. You can access the Google Play Store directly on your wrist, download standalone apps like Spotify, use Google Wallet for contactless payments and seamlessly navigate using a native Google Maps interface directly on the display.
Performance & Daily Use
Living with these watches day-to-day reveals the true trade-offs of their software choices. The user experience on the Xiaomi Watch S5 vs OnePlus Watch 3 comes down to whether you want a notification viewer or an interactive communication hub.
Xiaomi’s HyperOS 3 feels incredibly snappy. Swiping through the widgets, opening the heart rate app or scrolling through your notification list is fluid and lag-free. The sensors respond instantly when you raise your wrist to wake the display. However, because it isn’t a heavy-wear operating system, your interaction with notifications is limited. When an email or text comes in, you can read the text clearly on the beautiful display, but your ability to reply is restricted to preset quick responses. You cannot pull up a full keyboard to type out a custom message on the fly.
The OnePlus Watch 3 feels like a tiny smartphone on your wrist. Powered by the Snapdragon W5 Gen 1 processor and backed by 2GB of RAM and 32GB of onboard storage, its performance is incredibly powerful. When a text message comes through, you can type out a complete customized response using a full on-screen QWERTY keyboard or dictate your reply using Google Assistant voice-to-text. It handles background tasks effortlessly, allowing you to stream music directly from your watch to your open-ear headphones during an outdoor workout without needing to bring your phone along.
Who Should Buy Which Watch?
Buy the Xiaomi Watch S5 If…
- You want longer battery life.
- Fitness and health tracking are your top priorities.
- You like customizing your watch with interchangeable bezels.
- You already use a Xiaomi smartphone or other Xiaomi devices.
- You want over 150 sports modes and detailed fitness insights.
Buy the OnePlus Watch 3 If…
- You prefer the Wear OS experience with Google apps.
- You want a larger, brighter display for notifications.
- You value a comfortable design for all-day wear.
- You own a OnePlus or Android smartphone.
- You want a smartwatch that balances productivity and fitness tracking.
Who Shouldn’t Buy Which Watch?
Avoid the Xiaomi Watch S5 If…
- You want a full Wear OS experience with Google apps.
- You need support for a large library of third-party apps.
- You prefer LTE/cellular connectivity.
- You mainly use an iPhone and want the best smartwatch integration.
Avoid the OnePlus Watch 3 If…
- You want the longest possible battery life on a single charge.
- You have an iPhone.
- You prefer extensive watch customization, like interchangeable bezels.
- Your main focus is advanced fitness tracking over smart features.
- You’re looking for a smartwatch that works best within the Xiaomi ecosystem.
Final Verdict
If I had to choose just one smartwatch, I’d go with the Xiaomi Watch S5. After using both, it simply felt like the more complete package for my daily routine. The combination of excellent battery life, reliable fitness tracking, premium build quality and the ability to customize its look with interchangeable bezels made it the watch I kept reaching for.
That doesn’t mean the OnePlus Watch 3 isn’t a great smartwatch, it definitely is. But if I’m spending my own money and can only pick one, the Xiaomi Watch S5 offers the better overall experience and delivers more value for the price, making it my personal recommendation.
