OnePlus Watch 3 43mm Review: The compact battery champ

Phone Arena

08-07-2025

How can you stand out in the smartwatch space where Apple Watches, Samsung Galaxy Watches, and Garmin devices already have their loyal fan base?
OnePlus thinks it can do something better: a true smartwatch with double the battery life of an Apple Watch or a Galaxy Watch.
And now, after first releasing that earlier with the 46mm OnePlus Watch 3, the company is back with the OnePlus 3 43mm, a much more compact watch that still retains its battery advantage.
The OnePlus Watch 3 43mm is stylish and elegant, but it's also lightweight and compact, which you could not say about the larger version. The secret behind its longer battery life is a
dual-engine architecture.
The watch automatically switches between a low-power chip and a regular one without you ever noticing, maximizing battery efficiency. Add to that solid GPS performance, good heart rate accuracy, and all the essential workouts, and you have a very enticing Wear OS watch.
Is that a recipe destined for success, or should OnePlus just not bother with smaller wearables?
Stainless-steel case
Elevated digital crown that rotates
354mAh battery (compared to 631mAh on 46mm model)
Standard use battery life of 60 hours (vs five days on 46mm model)
Lots of good-looking watch faces (but don't use them if you want the best battery life)
Very fast charging (10 minute charge gives you 24 hours of use)
The 43mm OnePlus Watch 3 comes in two colors: Silver Steel and Black Steel, with a matching color fluoroelastomer strap.
The shiny stainless-steel body definitely elevates the look of this watch.
The key here, however, is the smaller size and lighter weight. This is the perfect watch size for smaller wrists, and it is extremely comfortable to wear for longer periods of time, including sleep.
As far as hardware specs go, here's what the OnePlus Watch 3 43mm gives you:
OnePlus Watch 3 43mm and its accessories (Image by PhoneArena)
Inside the OnePlus Watch 3 box, you will find the following: OnePlus Watch 3
Charging base
Strap
User Manual
USB-C charging cable
The new smaller-sized version of the OnePlus Watch 3 is a more compact and significantly more elegant take on the company's larger smartwatch. Measuring 43mm across and devoid of the rugged and more masculine aesthetics of the regular OnePlus Watch 3, this new arrival to the smartwatch scene is sleeker and more elegant, with a flat design that makes it appear significantly smaller than it actually is. Weighing just 59 gr with the stock strap, the OnePlus Watch 3 43mm is super easy to wear; sometimes you wouldn't even feel that it's on your wrist.
Although it would fit male wrists nicely, this one wouldn't look out of touch on a female wrist, which is something I can't say about the original OnePlus Watch 3—that one was obviously a masculine smartwatch.
The rotating digital crown is here, but the smartwatch lacks the elevated side bezel on the right, so the crown appears to be sticking out awkwardly a bit. The smaller-sized extra button is placed on the lower-right side of the case. The case is a stainless-steel one and doesn't have a large bezel like the titanium one on the bigger OnePlus Watch 3.
Speaking of the screen, we have a slightly slanted 1.32-inch AMOLED display with a decent sharpness of 352ppi (way above what Apple considers "Retina," for example). There's no sapphire here, just regular 2.5D glass.
The peak brightness is fine but is significantly lower than most other smartwatches, including the original OnePlus Watch 3. It maxes out at 1,000 nits, which pales in comparison with the 2,200-nit peak brightness of the larger model. This means you might have some legibility issues in very bright environments.
Just like its bigger brother, the new OnePlus Watch 3 boasts an IP68 rating along with 5ATM water resistance. Missing here is the MIL-STD-801H shockproof rating that the OnePlus Watch 3 had. This means that you should pamper this one and try to avoid bumping into edges, corners, and boulders.
The watch comes in Silver Steel and Black Steel, and the lighter version is definitely aimed at the more feminine part of the populace, while the darker version could be comfortably worn by men as well.
OnePlus Watch 3 43mm in Black Steel and Silver Steel colors
The OnePlus Watch 3 43mm doesn't introduce a new band attachment mechanism. It features standard 18mm lugs, allowing you to swap the stock fluoroelastomer band with any 18mm one you might have lying around. The stock band has a nice quick-release mechanism, and we see nothing wrong with OnePlus keeping things simple.
OnePlus Watch 3 Software & Features
Just like the OnePlus Watch 3, the smaller version also comes with two chipsets and two operating systems.
In smart mode, the watch is run by a Snapdragon W5 Gen 1 chip with Google's WearOS 5 on deck. In this mode, you can use the watch normally, download apps, and enjoy all features on deck.
When the battery level falls beyond a certain percentage, or if you deliberately enable the power-saver mode, the BES2800BP chip and the RTOS operating system take the reins. While visually the interface doesn't differ too much from the WearOS one, but you only have access to more rudimentary and basic functionalities.
Most watch faces are replaced with basic ones, third-party apps and tiles are unavailable, some complications may fail to showcase data, SOS calls are unavailable, and most accessibility features are disabled. Only workouts and most health features are available, and you can still receive notifications. This mode extends the battery life up to a week here, which is pretty much unmatched.
Back to smart mode, most of the features of the OnePlus Watch 3 are still available on the new version. For example, you get customizable new video/photo watch faces, while stock watch faces are way more customizable than on the OnePlus Watch 2 generation.
Performance is pretty decent. In smart mode, the OnePlus Watch 3 43mm treats us to a fluid interface with more than enough responsiveness. There's 2GB of RAM and a generous amount of 32GB of storage, which is more than enough to store all your music, apps, and other data.
The wearable is only compatible with Android devices, with the OHealth app acting as a software hub for all features and health-related data. As before, you can't use this smartwatch with an iPhone.
The activity loadout is similar to the one on the OnePlus Watch 3, including more than a hundred different sports and activities, including eleven professional sports. Tracking each activity gives you a data-rich dashboard that can be customized with the type of data you wish to see.
In running, for example, you get cadence, stride length, GTC (ground contact time), vertical amplitude, vertical stride, running power, and more. When tracking tennis, you get to see your swing speed, total strokes, serve, forehand, and backhand data. Swimming lets you track your 100-meter pace, number of laps, distance, swolf, and number of strokes. Walking lets you track your distance, number of steps, and cadence.
The OnePlus Watch 3 43mm comes with a GPS that supports all the essential technologies, like Galileo, Beidou, GLONASS, QZSS, and GPS itself.
The problem here is the fact that the GPS is a single-band one, which could introduce some issues when tracking your activities in dense metropolitan areas. The larger OnePlus Watch 3 comes with dual L1+L5 GPS, which is better-suited to accurately measure your activities in the city jungle.
The omnidirectional antenna from the larger Watch 3 also seems to be missing here, probably due to space constraints. Sleep tracking
Like its bigger brother, the OnePlus Watch 3 43mm comes with very detailed sleep tracking reporting. Your sleep gets broken down into the four main categories: deep sleep, light sleep, REM, and awake duration. Each category shows your result compared against the ideal length, which lets you identify issues with your sleep. For every one of your sleep sessions, you get awarded a Sleep Score, naps included.
The smartwatch will also track your vital signs during sleep, monitoring your respiratory rate, and even identify breathing problems and detect snoring if you enable the respective feature.
This watch lacks some of the core OnePlus Watch 3 health features, like ECG, Vascular Age, and 60S Health Check-in. That one required you to hold your finger on the digital crown for a minute to give you a complete report of all your health and wellness metrics, like hearth health, arterial stiffness, breathing issues, and more.
The new feature coming with the smaller OnePlus Watch 3 is female cycle tracking. It can predict upcoming menstrual cycles and ovulation windows, while users can log in symptoms and other changes. I assume it works alright.
Just like the larger watch, mental health monitoring is fairly important here. The watch will take your heart rate variability, heart rate, and your activity levels throughout the day to deliver an estimation of your physical and mental health. The interface of the respective Mind and Body tile is updated with more friendly graphics, making it easier to track your moods.
I noticed that the new watch thinks I am way less stressed than its predecessor did, which is peculiar. I haven't had any major changes in my lifestyle, so it could either be a false positive or OnePlus has changed the algorithms, behind the feature; I shall report back if I notice a correlation.
The 43mm version of the OnePlus Watch 3 comes with a 354mAh battery, notably smaller than the massive 631mAh one on the larger OnePlus Watch 3. Interestingly, battery life is halved across the board in comparison with the larger wearable.
OnePlus says we should expect up to 60 hours in smart mode and up to a week of usage in power-saver mode, while the larger watch offers up to 120 hours in smart mode and up to two weeks when you enable the power-saving mode.
This data is pretty consistent in my experience, and while everyone uses their wearables differently, I get around two and a half days out of the OnePlus Watch 3, with always-on display disabled and with all the sleep-tracking bells and whistles enabled.
Don't get me wrong, the battery life is still great here, but it's less impressive than the OnePlus Watch 3. Still, regular Apple Watches and Galaxy Watches still can't hold a candle to this wearable.
Charging is super fast thanks to the 10W VOOC wireless-charging puck. It takes just an hour to fully charge the wearable, but a quick 10-minute charge is more than enough to get you enough power to last through the day.
Like the larger watch, you can make and take calls with the OnePlus Watch 3 43mm. Audio is fairly decent, with the quality sufficient and the loudness fairly good.
The haptics are strong, but once again a bit too high-pitched and distracting for my taste. I miss the stronger thump of an Apple Watch or a Galaxy Watch here, but for the most part, the haptics are okay.
Naturally, it's Samsung's smartwatches that are the most popular among the Android crowd, and rightly so: they pair friendly design with great health and wellness features. However, their battery life won't be comparable to the OnePlus Watch 3 43mm, which will most certainly have them beat.
The upcoming Apple Watch Series 11 , on the other hand, also won't be able to match the great battery life of this here OnePlus smartwatch. An Apple Watch naturally fits extremely nicely into the Apple ecosystem, and has all the health and fitness features you might want.
No two ways about it, the OnePlus Watch 3 43mm is a compromise in most areas, offering a slightly worse experience in comparison with the standard OnePlus Watch 3.
The most essential feature of any smartwatch, the battery life, is halved here, mostly due to the design constraints. Some not-so-essential but still nice-to-have health features are missing, and the watch can't get as bright as its bigger brother, which is something you'd have to learn to live with.
Then again, when you compare this OnePlus Watch against the non-OnePlus WearOS competition, it shines rather brightly. It has better battery life than most WearOS devices you might get, an equal feature and functionality set, and a design language that's super lovely! Another ongoing criticism with OnePlus' smartwatches is the lack of a cellular version for sale: regardless of what you do with your watch, you will need to have your Android phone close by; otherwise, you're left with a digital watch that merely tracks your steps.
Would I recommend getting this one? Yes, despite its flaws, it's excellent value for money, especially if you're sick of super-large smartwatches.