Review: Xiaomi Watch S3

The Xiaomi Watch S3 is an affordable smartwatch with a highly customizable look that includes swappable bezels. It can track your health, fitness, and sleep, bring phone notifications to your wrist, and last several days between charges. The downside? It runs Xiaomi’s software, which feels a bit basic, and you can forget about third-party apps.

Closing in on a month with the Xiaomi Watch S3, I’m impressed by its tracking capabilities, considering the relatively low price, and the changeable bezels are a neat idea. But I’m also fine with saying goodbye to it. The Watch S3 has too many limitations for me, but it’s important to remember that this device is less than half the price of the most affordable option in our best smartwatches guide.

Before we dig in, it’s worth noting that there is a global version of the Xiaomi Watch S3, but it's not sold in the US, there's no official US support, and certain features (like NFC for payments) vary by region.

Smartwatch Chameleon

For folks who like to match their watch with their outfit, the Xiaomi Watch S3 has a unique trick up its sleeve in the shape of interchangeable bezels. Changing the strap on a watch can be impactful, but being able to change both the strap and bezel almost makes it look like a completely different device.

The Watch S3 has quite a chunky 47-mm aluminum case with angled lugs and two buttons on the right. A stainless steel bezel sits on top of the screen, and you can rotate it to remove and replace it with a different bezel. It’s easy once you get the hang, and there’s a wee marker on the inside to help you align. The bezels slot into place securely, and I never worried about them coming loose.

Attach a new bezel and the Watch S3 suggests a matching watch face. It's a neat trick. There are more than 100 watch faces in every conceivable style, and you can even create your own. Changing the strap is also straightforward, so you can quickly change your look. My favorite of the straps and bezels Xiaomi sent was the classy green and black combo. You get one black or silver bezel with a matching fluororubber strap with the Watch S3, and alternatives must be purchased separately.

The 1.43-inch AMOLED screen has a layer of protective Corning glass. The display is roomy and crisp, but the relatively low peak brightness of 600 nits (a luminance measurement) meant it was sometimes hard to read in direct sunlight. The Watch S3 is also 5ATM rated for water resistance, meaning you can swim with it.

Streamlined for Stamina

The Xiaomi Watch S3 focuses on the basics with call and notification alerts from your phone; health, fitness, and sleep tracking; and a handful of utilities like a voice recorder, camera shutter control, and compass. It runs HyperOS, so there are no third-party apps like you will find on a Google Wear OS smartwatch.

Navigating around the Watch S3 is slick and lag-free. HyperOS is not the most attractive software and lacks a cohesive design, with a mix of dull and garish icons. But it mostly worked well, aside from the odd missed notification from my phone. It connects via Bluetooth 5.2, and you can use it with any phone running Android 8 or iOS 12 or later. I tested with the Xiaomi 14 Ultra.

There are 30 apps on the Watch S3 covering most bases. There are music controls (they worked fine with Spotify), a dialer app, and a notes app. There is an NFC wallet for payment cards that works with Xiaomi Pay, but it is limited to Mastercards with specific banks (mine was not listed). There is also an Amazon Alexa app, giving you access to the voice assistant if you sign into your Amazon account. While the notes app on the 14 Ultra syncs tasks with the Watch S3, don’t expect the tight integration you get with the Apple Watch and iPhone. Weirdly, the voice recorder app just records to the watch, and I couldn’t find a way to export the recordings.

While the Watch S3 can mirror notifications from your phone, they are one-way, so you can’t reply to text messages from your wrist. You can make and take calls from your connected phone as the Watch S3 has a mic and speaker, but the sound quality is poor, so I’d only do so in a pinch. The main thing I missed was navigation support because there’s no Google Maps or equivalent.

The main benefit of Xiaomi’s streamlined approach is excellent battery life. Xiaomi claims that the 486 mAh battery inside the Watch S3 can go for up to 15 days, but if you activate the always-on display and max out the frequency of the health tracking features, as I did, you can expect to go four or five days between charges. That’s still very good, and it means you can take a weekend trip with the S3 without worrying about packing its charger.

It takes around an hour to fully charge the Xiaomi Watch S3 using the proprietary magnetic two-pin charger in the box. The Watch S3 doesn’t support wireless charging, but the charging puck is at least backward compatible, so it works with older Xiaomi watches.

Tracking and Software

For folks keeping a casual eye on health and fitness metrics, the Watch S3 ticks all the boxes. You must install the Mi Fitness app on your phone to configure and sync data from your Xiaomi Watch S3, but it’s pretty straightforward, with a tab for all your health and fitness data, including sleep tracking, heart rate, step count, calories burned, and a few other things. You can also share your data with Google Fit, Apple Health, Strava, or Suunto. The device tab shows your connected Watch S3 and lets you dig into alternative watch faces, app notifications, and other settings.

The health tracking is solid, though some folks may have concerns about sharing the kind of personal data a smartwatch collects with Xiaomi (here’s Xiaomi’s privacy policy). The 12-channel PPG (photoplethysmography) optical heart rate sensor can track your heart around the clock, but more frequent readings drain more battery life. It tallied with my Apple Watch Series 9 (7/10, WIRED Recommends), occasionally straying by three or four beats during workouts.

There is a comprehensive list of workout modes (around 150), and the Watch S3 can automatically recognize and track runs. It also has GPS (dual-band GNSS) to track your routes outdoors. My step count was within a hundred of the Apple Watch's at the end of the day. The blood oxygen tracking (SpO2) also seems to work fine (as with most smartwatches, the readings are all offered as rough approximations).

Sleep tracking was broadly correct. The Watch S3 was quite good at telling when I had fallen asleep and tracking overall hours of slumber. However, when I compared the data with other sleep trackers, it was clear that the Watch S3 consistently overestimated how long I spent in the deep sleep phase. After a week of sleep tracking, it tells you what sleep animal you are (I was a koala). While it’s not especially heavy (44 grams without the strap), you know you’re wearing it, and the bulk sometimes annoyed me at night.

The Watch S3 also has an accelerometer, gyroscope, electronic compass, barometer, ambient light sensor, and hall sensor. The raise-to-wake function works well and can save some battery life. You can also use the gimmicky customizable quick gestures by rotating or shaking your wrist to ignore a call or launch Alexa. There are a few other options, but the photo shortcut did not work for me, even using the Watch S3 with a Xiaomi 14 Ultra.

There’s no denying you get lots for your money, even if you add another bezel and strap (ranging from around £10 to £30). The Watch S3 is currently offered at £120 in the UK, and I’m hard-pressed to find an alternative smartwatch with a similar feature set that isn’t significantly more expensive. If you want WearOS, there’s the Xiaomi Watch 2 (£170), though it lacks the switchable bezels. Some of the best fitness trackers are similarly inexpensive. But as a budget smartwatch, the Xiaomi Watch S3 is tough to beat.