It is hard to deny that Xiaomi has been on a solid run lately, releasing some of the most exciting smart devices, phones and other tech. The company seems firmly committed to disrupting the status quo of dominant players like Samsung, Google and Apple. The Xiaomi Watch S4, released in early 2025, exemplifies this strategy—a device that blends customizable design, robust fitness tracking and exceptional battery life at a price that undercuts rivals while still looking stunning.
After two weeks of testing, I am pleased to say the Xiaomi Watch S4 is an exciting option for users seeking value without sacrificing core features. While it stumbles in areas like app support, its strengths make it one of the year’s most intriguing wearables.
Unboxing the Xiaomi Watch S4 was a simple affair, with the watch arriving in a sleek black box containing just a charging cable and nothing else. However, it’s the accessories that elevate this straightforward device into something truly special.
The Watch S4 features an interchangeable bezel system that lets you quickly swap out the bezels, along with the 22 mm quick-release straps, allowing you to tailor the look to suit your style. The silver model tested here, with its high-gloss PVD finish, mimics the elegance of stainless steel, while the rainbow and black variants cater to bolder tastes.
At 47.3 mm, the case leans large, but the 12 mm thickness and 70 g weight (with straps) ensure it sits comfortably even on smaller wrists. The rotating crown and side button provide tactile navigation, though their fixed functions limit customization. With water resistance up to 5 ATM, it easily withstands swims and showers, while the sapphire-coated 1.43-inch AMOLED display resists scratches—something my clumsy self is very grateful for.
You could be forgiven for thinking the Watch S4 is a much more expensive offering than it is, thanks in part to its stunning 466×466-pixel panel that reaches 1,500 nits of brightness (2,200 nits in peak mode). This ensures readability even under direct sunlight—something runners and hikers will appreciate. HyperOS 2.0, Xiaomi’s lightweight operating system, delivers smooth animations via a 60 Hz refresh rate. Swipe gestures feel intuitive: swipe down for notifications, up for widgets and left to cycle watch faces.
Yet, as much as I like HyperOS 2.0, it does have its limitations that competitors like Apple simply do not face. The absence of third-party apps—a glaring omission compared to WearOS or watchOS—means users must rely on Xiaomi’s preloaded tools. While essentials like weather, timers and music controls are present, those hoping to control apps like Spotify or respond to messages on WhatsApp will be out of luck. Still, the availability of plenty of free watch faces (many customizable) helps soften the blow, with options ranging from minimalist analog designs to data-rich fitness dashboards.
“Sleep analysis proved detailed on the Xiaomi Watch S4 smartwatch, breaking cycles into light, deep and REM stages.”
Even if the Watch S4 lacks third-party app support, fitness is where it truly shines. Xiaomi has equipped the watch with sensors, including 24/7 heart rate monitoring, SpO2 tracking, stress monitoring and sleep tracking.
During testing, heart rate accuracy seemed relatively good, especially for the everyday activities I was doing—running around MWC—and provided a reliable sense of overall health throughout my day-to-day fitness routine. It should be more than sufficient for those looking for casual tracking. However, for anyone serious about fitness, medical-grade devices are always preferred—especially for intense training. Sleep analysis proved detailed on the Xiaomi Watch S4 smartwatch, breaking cycles into light, deep and REM stages.
The 150-plus sports modes cover everything from boxing to bridge—a comically broad range that underscores Xiaomi’s “something for everyone” approach. Automatic workout detection remains inconsistent. A 90-minute walk triggered recognition only after 70 minutes, likely due to frequent stops. However, for the most part, Xiaomi has nailed the main uses, and any inconsistencies I noticed could easily be addressed in future updates.
While I have been a bit lukewarm on some of the features, battery life is one area where the S4 truly dominates. With the always-on display disabled and moderate use, it lasts 12 to 15 days—double the lifespan of most Wear OS watches. Even under heavy load (continuous GPS and maximum brightness), it manages 5 to 6 days. A quick 5-minute charge grants two days of power, which is a lifesaver for forgetful users.
I have praised OnePlus for delivering impressive battery life with their Watch series, and Xiaomi is coming in hot on their heels. The Apple Watch has improved since its initial release, but it gets nowhere near the battery life I achieved with the Watch S4. I was comfortable relying on the S4 throughout my entire time at MWC 2025, and it wasn’t until I was heading home that the battery finally reached the 20 percent range—and that was after a full trip of heavy use.
Bluetooth calls work flawlessly, with clear audio from the built-in microphone and speaker. Notifications are readable but lack reply options—an oversight in an era when quick Messenger responses are expected. Gesture controls, such as wrist flicks to dismiss calls, proved finicky at times.
There’s a bit of a gimmick to how some of the gestures work, but once you get the hang of them, they function as intended and offer good control over how the watch operates in daily life. Additionally, if you are invested in the Xiaomi ecosystem of smart devices, the S4 integrates seamlessly with everything, providing a nice bonus for those who have remained loyal to the brand.
After two weeks of testing, I have to say I was impressed. Granted, the Xiaomi Watch S4 isn’t the best at everything—except perhaps battery life—but it is good at most things, making it a solid offering overall. Its modular design, vivid display and robust health suite justify its $199 price, undercutting the Galaxy Watch 7 by more than $150. While compromises like spotty GPS and limited app support prevent it from being perfect, it’s more than enough for 95 percent of users looking for a smartwatch. The Xiaomi Watch S4 may be all you ever need.
