Xiaomi’s Watch S3 is one of the best affordable smartwatches out there

The Xiaomi Watch S3 was part of a trio of Xiaomi wearable launches designed to go big on health and fitness features at low prices.

Sitting in between the Watch 2 and the Smart Band 8 Pro, the S3 is a fully round smartwatch that lets you whip the bezels on and off for different looks and includes features you typically don’t expect to find on a watch at this price – just £129.99 in the UK – like a dual-band GNSS mode to give outdoor exercise tracking accuracy a boost.

It’s a smartwatch not striving to directly compete with smartwatch big hitters from Apple, Google and Samsung, but that doesn’t mean it wants to shortchange you on performance either. The Xiaomi Watch S3 certainly promises a lot for less and manages to deliver on most of what it’s promising.

Check out our chart of the best smartwatches to see alternatives.

Design & Build

• Works with interchangeable bezels
• Black or silver colours
• 5ATM waterproofing

Out of the box, the Xiaomi Watch S3 clearly feels like a well-built watch if a little on the unoriginal side in look.

There are two colour options – black or silver, and I had the black version to test, which is matched up with a pretty standard fare flurorubber strap that’s been comfortable to wear and easy to get on and off.

You do also have the option to opt for a leather strap, which you might want to do if you like the look of Xiaomi’s more intriguing bezels.

Mike Sawh

The case body is made from an aluminium alloy with a stainless steel bezel giving the watch a nice weight and that bezel does have a special trick, which sets the S3 apart from rivals. You can quickly twist the bezel to remove it, letting you swap in additional bezels to change the look of the watch.

The removable bezel included is a pretty plain affair but I did have an additional ceramic one to put in its place, which certainly gives the S3 a more eye-catching look. A nice added touch when you add in a new bezel ring is that it suggests a watch face to compliment it.

Mike Sawh

Outside of that removable bezel Xiaomi keeps things simple elsewhere. There are two physical buttons that sit pretty flush with the right side of the case.

There’s the optical sensor around the back where you’ll also drop it on the disc-shaped charging cradle. A 5ATM waterproof rating means you can go swimming with it as long as you’re not going deeper than 50 metres, which seems unlikely for most people.

Screen & Audio 

• 1.43-inch AMOLED display
• Supports always-on mode
• Includes microphone and speaker

It’s always pleasing to find a good quality colour screen on a cheap smartwatch and that’s exactly what you’ll find on the S3.

It’s a not too hulking 1.43-inch, 466 x 466 resolution AMOLED touchscreen that can be set to always-on. There is a smart always-on display mode to give you the best level of battery life by keeping the screen on when you need it most.

There’s also a nicely responsive raise-to-wake gesture support if you value having more battery life instead.

Mike Sawh

Mike Sawh

Mike Sawh

The display is vibrant and bright maxing out at 600 nits, though there’s some fuzziness around the icons and some colours are a touch oversaturated. It doesn’t hamper the experience, but it’s a sign you’re not getting the best of the best here. 

Xiaomi does find room for a microphone and speaker enabling you to take calls from your wrist, as long as it’s paired to your smartphone over Bluetooth, of course. You can bring up a keypad that fills the screen and call quality is good enough to make it usable as a wrist-based phone, though it does struggle in noisier environments.

Software & Features 

• Runs on Xiaomi’s HyperOS
• Contactless payments via Mastercard
• Compatible with Android phones and iOS

Unlike the Wear OS-packing Xiaomi Watch 2, the Watch S3 runs on Xiaomi’s own HyperOS. It’s a version of the operating system that’s also packed onto Xiaomi’s phones, TVs and smart home tech among other devices.

It is an operating system that plays nice with iPhones and Android phones and my testing with an iPhone saw no connection pairing or syncing issues.

Mike Sawh

Mike Sawh

Mike Sawh

It’s a predominantly gesture-based experience, so swipe left and right to see your widgets packed with information like heart rate, music controls and alarms. There’s no bad lag and the software runs nice and smooth overall.

There’s a clearly Apple-inspired, but certainly more basic, hands-free mode where you can flick or shake your wrist to answer or reject calls, open your voice assistant, take a photo or check in on the weather.

The top physical button launches the app tray and the bottom one gives you quick access to the workout tracking screen. Notification support works well and is optimised to the S3’s screen and while you can merely dismiss notifications, they are nice and easy to glance and absorb on the move.

Xiaomi offers a decent array of core smartwatch features here. You’ve got Amazon Alexa to tick the smart assistant box, the onboard music player is an Android-only feature, though unlike other smartwatches doesn’t work with third-party music services to let you load on offline playlists. 

The core smartwatch experience is actually very good. It’s not as clunky as it can be on smartwatches at this price and a big part of that is down to the very well-functioning HyperOS, which shows Xiaomi is listening and refining its operating system.

The contactless payment support that will only work with Mastercard pay terminals which could be a pain and the watch face options are pretty extensive with more available via the app.

Fitness & Tracking 

• Over 150 sports modes
• Dual-band GNSS mode
• 12-channel, optical heart rate monitor

The Watch S3 has the sensors and the modes to be a smartwatch that can do everything from track your heart, sleep, runs, pool swims, help you relax with breathing exercises and even tell if you’re in good training shape.

On the sensor front, you’re getting a pretty typical set of motion and optical sensors including a 12-channel heart rate sensor that promises a heart rate accuracy of 97.95%.

There’s an automatic activity recognition mode for activities like running, walking and indoor rowing and Xiaomi even manages to find room for a dedicated ski mode. There’s built-in GPS to track outdoor workouts and a dual-band GNSS mode to boost outdoor tracking accuracy, which is rare to find on a watch at this price.

Mike Sawh

Mike Sawh

Mike Sawh

As far as being a smartwatch I’d trust to do all of these things it’s a case of being good at some things and not quite so reliable enough for other things.

If you’re relying on it to be your daily fitness tracker to track your daily steps, heart rate, stress and sleep I’d say the S3 does a good job. I found daily step counts were around 500-800 steps out from similar tracking on a Garmin watch and an Oura Ring Gen 3 I wore alongside it.

When continuously monitoring heart rate, daily resting heart rate averages were nicely in line with Garmin’s very reliable tracking and while maximum readings during the day didn’t entirely match up, they also weren’t wildly out either.

When you take the watch to bed you’re going to capture sleep duration, sleep stages including REM, average heart rate and get a sleep score, which is also compared to other Xiaomi users. You’ll also be assigned a sleep animal once you’ve worn the watch to bed for seven nights.

Data like sleep duration, sleep stage breakdowns and sleep scores are close to the Oura Ring Gen 3, one of the best sleep trackers I’ve tested. The presentation of the data in the Mi Fitness app is pretty basic, but that’s not necessarily a bad thing here and makes it easier to glean on the most useful stats.

Mike Sawh

Mike Sawh

Mike Sawh

In terms of sports tracking, you have 150 sports modes to pick from and that includes pool swimming, outdoor cycling, hiking and, of course, running. Runners can also benefit from accessing running courses to get new runners familiar with different types of training runs; whether that’s following a run/walk session or taking on your first interval run.

You also get that aforementioned dual-band GNSS mode, which aims to improve outdoor tracking accuracy when using the watch near tall buildings, deeply forested areas and adverse weather. This is a key reason for some to buy it over rivals.

I’ve run (indoors and outdoors), used it for indoor rowing with and without the automatic activity recognition mode and used it for pool swims. For treadmill runs, the tracking accuracy came up pretty short on distance tracking next to a dedicated running watch. That created a problem calibrating as the difference between the recorded distance and actual distance was so big it didn’t give me a big enough range to calibrate it.

For outside runs, it underreported distance on all of our runs and the average pace timing wasn’t quite right either. Heart rate tracking accuracy wasn’t great at all, with average and max readings well off from the gold standard tracking on a heart rate monitor chest strap. Here’s hoping these issues can be improved with software updates but don’t count on it.

Mike Sawh

Mike Sawh

Mike Sawh

I also had problems syncing some of those runs to the Mi Fitness app as well. For pool swims, it put in a good performance against two other swim trackers for metrics like distance covered and average pace, though stroke counts seemed a little off.

While that data primarily lives inside of the Mi Fitness app, Xiaomi does allow you to send that data to Strava and now Suunto, and it did that with no problem and in a speedy fashion to the former.

If you’re planning to work out solo or you like the idea of raising the alarm if you get into trouble, Xiaomi does include some emergency assistance features letting you tap the bottom physical button three times to call an emergency contact. There’s also a fall detection mode here too, though without any sort of standalone LTE connectivity, you will need to be paired to your phone via Bluetooth to make these features useful to have at your disposal.

Battery Life & Charging

• Up to 15 days battery life
• Up to 5 days in always-on mode
• Supports quick charge mode

Xiaomi suggests you can get just over two weeks of time in between needing to drop the S3 on its charging cradle, though I’d say that number represents when you’re not putting all of its features to regular use.

The precise quoted numbers are 15 days when paired to an Android phone and 14.5 days when using it with an iPhone. That’s a lot more than WearOS rivals like the Google Pixel Watch 2 review and even Xiaomi’s own Watch 2.

Mike Sawh

Mike Sawh

Mike Sawh

If you’re planning to keep the screen set to always-on then that number drops to 5 days and if you’re using features like the most advanced health monitoring support, that will contribute to a more noticeable drop in battery.

I’ve found that daily battery drop-off was on average 10% and that was with the raise-to-wake in use and using features like music controls, notifications, continuous heart rate monitoring and using GPS. Switching the screen to always-on averages out to around 2-3 days. 

While not hitting those promised numbers, having a smartwatch that can last well over a week is still a good showing. You also have the added bonus of a very swift quick charge mode that will top you up with two days of watch time off a 5-minute charge.

Price & Availability

The Xiaomi Watch S3 was announced in February 2024, alongside the Xiaomi Smart Band 8 Pro and the Xiaomi Watch 2 and is available to buy from the Mi store and retailers including Amazon. It’s priced at £129.99, and that’s the same price for both black and silver versions.

If you want to pick it up in the US, Xiaomi doesn’t currently ship the Watch S3 from its own website, so you may have to do some hunting around to get hold of one Stateside.

That price puts it firmly in the cheap but not quite budget smartwatch category so sits alongside watches like the Amazfit Bip 5, Honor Watch 4, Huawei Watch Fit 2 and the Redmi Watch 4, which is built under Xiaomi’s affordable sub-brand and does share some software similarities to the Watch S3.

Oddly, the extra bezels are nowhere to be seen on the Mi store so we’ll update this review when they go on sale.

Check out our list of the best smartwatches for the top options.

Mike Sawh

Mike Sawh

Mike Sawh

Should you buy the Xiaomi Watch S3?

The Xiaomi Watch S3 is a pleasant smartwatch to live with and pick up if you’re on a tight budget but also don’t want to make major compromises on features and performance.

No, it doesn’t have Wear OS features like the pricier Xiaomi Watch 2, but the experience on the whole is very good and core smartwatch features perform well too.

When you look in and around the price of the Xiaomi Watch S3, it’s up against watches like the Amazfit Bip 5, Honor Watch 4 and the Redmi Watch 4. The Bip 5, along with the Honor and Redmi watches have blockier looks in comparison and it’s where the interchangeable bezels on the Xiaomi smartwatch really gives it something different.

Feature sets are largely similar across the board, though you won’t find dual-band GPS support on those other watches, which could swing it for runners though I found discrepancies in the other tracking data.

The Xiaomi Watch S3 is one of the strongest options at that more affordable end of the market, whether you’re an iPhone or an Android user, especially if you value a good-looking, round design with scope to tinker with that look.

Specs

• 1.43-inch, AMOLED always-on display
• 5 ATM water resistance rating 
• Built-in speaker
• Dual-band GNSS
• 486mAh capacity battery
• Up to 15 days battery life
• Heart rate sensor
• Blood oxygen sensor
• Bluetooth calls
• Sleep tracking
• Stress monitoring
• 44g (without strap)