OnePlus Watch 4 Review: The best Wear OS battery miracle of 2026?

With the Watch 4 presented in April, OnePlus has consistently developed its flagship smartwatch further. A full titanium case, Wear OS 6, Google Gemini and a battery life that is hard to beat on the market. On paper, that sounds convincing. I have worn the watch intensively for several weeks and will see whether the OnePlus Watch 4 lives up to this promise in everyday use.

Technical data of the OnePlus Watch 4

Product name	Watch 4
Operating system	Android; iOS
Bluetooth	Bluetooth 5.2
Features	Acceleration sensor, Gyroscope sensor, Optical heart rate sensor, Optical blood oxygen sensor, Wrist temperature sensor, Geomagnetic sensor, Ambient light sensor, Air pressure sensor, NFC, Google Wallet, Gemini
Display	LTPO-OLED (466 x 466 pixels); 3,000 nits
Water resistance	5ATM, IP69
Battery life	Up to 16 days (energy-saving mode); Up to 5 days (smartwatch mode)
Weight	43 grams
Price	€ 208.96 * (€20 off with code DE6SS20 until June 10, 11:59 PM – only €188.96)

OnePlus Watch 4 review: design and workmanship

First impressions count and the OnePlus Watch 4 makes a very good first impression. The case is made entirely of titanium alloy and is available in two colors: Midnight Titanium and Evergreen Titanium. That doesn’t just sound classy, it feels classy too. The rivet detailing on the bezel looks well thought out and gives the watch an industrial yet elegant aesthetic that can be worn both in the office and during sports.

Compared to its predecessor, the Watch 4 is 13 percent lighter and 6 percent thinner. With a height of 11 mm, it weighs just 43 grams. This is noticeable on the wrist: I wore the watch several times overnight without it disturbing me while I slept. This is by no means a matter of course for a 47 mm watch.

The display is protected by sapphire crystal, which reliably prevents scratches in everyday use. The 1.5-inch LTPO AMOLED panel has a resolution of 466 x 466 pixels at 310 PPI and achieves a brightness of up to 3,000 nits. The content remains easy to read even in direct sunlight.

The Watch 4 meets the military standard MIL-STD-810H, supports operation with wet hands and is fully resistant to seawater corrosion. It has IP68 and IP69 protection classes. In everyday life this means: swimming, rain, sweat, no problem. I have worn the watch while swimming and in the shower without even thinking about taking it off.

However, the size remains a real point of criticism. OnePlus is also sticking to a single, large-format case with the Watch 4, which again measures around 47 mm. A smaller version will not be available at launch. Those with small wrists will find the watch difficult to wear. Wearing comfort and heart rate measurement during intensive training may suffer as a result. This is a noticeable shortcoming, especially for users in the target group.

Equipment and features of the OnePlus Watch 4

Under the hood, the OnePlus Watch 4 relies on a dual-engine architecture. The Qualcomm Snapdragon W5 Gen 1 is used as the processor, which is supported by a BES2800 co-processor. It also has 2 GB of RAM and 32 GB of internal memory. This is easily enough for smooth Wear OS navigation, fast app launches and local music storage.

The operating system is Wear OS 6 with OxygenOS Watch 8 as the interface. The Watch 4 is one of the first devices to be launched with Wear OS 6 straight from the factory and comes with a more polished interface, smoother animations and deeper integration with Google features such as Gemini.
Google Gemini can be activated directly via the watch. Messages can be sent, tasks completed and complex questions asked via “Hey Google”. All without having to take your smartphone out of your pocket. In practice, this works reliably as long as you are within Bluetooth range of your smartphone.

In terms of health tracking, OnePlus is introducing a function called “60-Second Wellness Overview”, which I find surprisingly useful in everyday life. In a single 60-second measurement, the watch records up to nine indicators from the areas of heart health, sleep and mental well-being. These include heart rate, blood oxygen, body temperature and stress level. This provides a quick overall picture without having to call up different apps individually.

Over 100 sports modes are available, 11 of which have a dedicated professional sports mode. These include running, cycling, tennis, badminton, indoor swimming and skiing. For ambitious runners, the watch offers a pace assistant that tracks the deviation from the target pace in real time. Lactate threshold tracking is also on board, but requires at least one completed outdoor run in order to generate valid data.

The GPS system supports L1 and L5 bands as well as GLONASS, Galileo, BDS and QZSS. In my outdoor tests, the position detection was precise and fast. What’s missing: In this price range, the lack of ECG and eSIM is noticeable. Both are offered by competitors such as the HUAWEI Watch FIT 5 Pro (our test) or the Google Pixel Watch 4. If you need LTE connectivity or a medically certified ECG function, you will still have to choose a different device. NFC-based mobile payment is also not available, depending on the region.

Impressive battery life: up to 5 days

Battery life is the key selling point of the OnePlus Watch 4 and it delivers here. According to the manufacturer, the watch lasts up to 5 days in smart mode and up to 16 days in energy-saving mode. In my test with the always-on display activated, continuous health monitoring and daily workout tracking, I consistently achieved a good four days. This is simply outstanding in the Wear OS segment and corresponds to values that we otherwise only find on the Huawei Watch GT 6 (Pro) and other devices from the manufacturer.

This value is identical to that of the predecessor OnePlus Watch 3, which shows that OnePlus has maintained the already excellent level, but has not developed it further. Those coming from the Watch 3 will therefore not notice any difference in this respect. For newcomers to the OnePlus ecosystem, however, the battery life is still a clear selling point compared to alternatives such as the Galaxy Watch8 (which typically has to be plugged in after two to three days) or the Pixel Watch 4.

One practical caveat: in order to achieve the maximum values, the watch switches off certain health features and the always-on display by default. Users who want to have all features active at the same time will end up well below the advertised figures. This is not a deal breaker, but should be taken into account when purchasing.

App connection via OHealth

The OnePlus Watch 4 runs Wear OS 6 and is therefore fully integrated into the Google ecosystem. Google Pay, Google Maps, Google Wallet and the entire Play Store for smartwatch apps are available. This is a clear advantage over proprietary operating systems.
OnePlus relies on the OHealth app for health and fitness data. The app requires an Android device with at least Android 9.0 and GMS version 23.45.23 or higher. iOS devices and Android Go versions are not supported. This measurably limits the user base. Anyone with an iPhone or an Android device without Google services is left out.

Many of the most advanced features, especially professional running analysis and specific health syncs, primarily work optimally in combination with a OnePlus smartphone. Basic functions can be used on other Android devices without any problems, but the full potential unfolds in the OnePlus ecosystem. This is a familiar pattern with manufacturer smartwatches, but it limits flexibility.

The Gemini integration works reliably in everyday life: voice commands are processed quickly, messages are dictated and timers are set without picking up the smartphone. Overall, the operating speed is good by Wear OS standards. I noticed occasional delays in notifications, but they remained the exception.

OnePlus Watch 4 in the practical test

During several weeks of everyday use, the OnePlus Watch 4 impressed me in several respects and also disappointed me in some areas. The titanium case leaves no scratches after weeks of wear and the brightness of the display is sufficient for problem-free reading even in bright sunlight. The watch passes the MIL-STD-810H military standard in 16 categories, including salt spray, sand dust, temperature fluctuations and shock load. This certification is not just an abstract promise in the practical test: I wore the Watch 4 while swimming in an outdoor pool and on a hike lasting several hours, and it took it all in its stride without complaint. Even when I accidentally bumped it against door frames and desk edges, the sapphire crystal did not show any signs of damage.

The 60-Second Wellness Overview has quickly established itself as a fixed morning routine. Tap it once, hold it still for 60 seconds and you get a complete overview of your heart rate, SpO2, stress, body temperature and sleep quality. Anyone who has previously called up various health apps individually in the morning will appreciate this summary straight away.

The measurement results appear plausible and accurate. The deviation in heart rate at rest was consistently less than two beats per minute. The values for the stress level and mental health indicators should be seen as a guide, not as a clinical diagnosis. In sports, the Watch 4 is particularly impressive when running. The Professional Running Mode provides detailed biomechanical data. Step frequency, vertical oscillation, ground contact time and running cadence, which offer real added value for ambitious amateur runners. However, I have to say that the Pixel Watch 4, for example, delivers more accurate results across the board.

The watch performs well in classic everyday smartwatch use. WhatsApp, emails, calendar entries and calls arrived reliably and with an acceptable delay. Direct replies by dictation via Gemini work smoothly as long as you are not standing in a noisy environment. The integrated loudspeaker is sufficient for short calls, but sounds thin as expected.

I have to mention the chip once again: The Watch 4 uses the same Snapdragon W5 Gen 1 as the Watch 3 and even the Watch 2. No upgrade to Qualcomm’s newer Snapdragon Wear Elite platform. In everyday use, the performance is smooth and app launches are fast enough not to be annoying. However, anyone switching from another modern Wear OS device will not experience a noticeable leap in performance. Especially in view of future Wear OS features and on-device AI processing (keyword Gemini), the decision to use the older platform feels a little short-sighted in the medium term.

If you actively use all the health features at the same time, you will also notice that the watch has to be plugged into the charging cable much sooner than the manufacturer’s glossy figures suggest. This is not a mistake, but a design decision: If you want maximum battery life, you have to prioritize features. If you want everything at once, you quickly end up withthree days instead of five.

However, two points annoyed me extremely in everyday use:

1. When I switch to bedtime mode overnight, the Watch 4 automatically switches to energy-saving mode. It then takes forever to wake up the next morning. From time to time, the wearable even hangs briefly. In addition, you have to deactivate energy-saving mode and then sleep mode separately.
2. The second problem follows on directly from this: After this annoying wake-up process, the watch is apparently no longer able to show the always-on display. Although the AoD is still activated, it is no longer displayed after waking up in the morning. The screen remains black. This can only be remedied by deactivating and activating the AoD (several times!). Incredibly annoying.

OnePlus Watch 4 Review: Conclusion

The OnePlus Watch 4 is a thoroughly successful flagship smartwatch with clear strengths and a handful of specific weaknesses. The full titanium case is noticeable every day in terms of feel, weight and robustness. The battery life is still unbeatable for Wear OS, Wear OS 6 with Gemini brings the platform noticeably forward and the display with its 3,000 nits is one of the best the market currently has to offer.

On the other hand: no LTE, no upgrade to newer wearable silicon platforms, no smaller case at launch. These are three points that are unlikely to persuade OnePlus Watch 3 owners to upgrade. Anyone expecting an ECG or blood pressure measurement will also have to look to the competition. An ECG function is almost standard on smartwatches these days. After all, it is integrated into the 60-second health check.

Then there are the aforementioned problems with the sleep mode and always-on display, which frankly annoy me to no end. Of course, OnePlus could get these under control with a firmware update, but at the moment it really bothers me. For everyone else (especially Android users who are investing in a premium smartwatch for the first time or switching from an older watch), the OnePlus Watch 4 is a good option in the WearOS cosmos. Even if it’s not the best choice.