Posted on March 06, 2025, by Tech Spurt, Smartwatch Expert

Looking for a smartwatch that blends style, functionality, and stellar battery life? The Xiaomi Watch S4, unveiled at MWC 2025, might just catch your eye. I’ve been wearing this sleek device on my wrist for the past couple of weeks, and I’m here to share my hands-on experience. From its unique customizable design to its rivalry with the OnePlus Watch 3, this Xiaomi Watch S4 review breaks down everything you need to know. Let’s dive in!

A Design That Stands Out: Customize Your Way

One of the standout features of the Xiaomi Watch S4 is its fluid design. Unlike most smartwatches, you can pop off the bezel and swap it with another to match your vibe. The standard 22mm straps are interchangeable too, giving you endless personalization options.

The review unit I tested came with a colorful strap that felt a bit too playful for my taste—think kid-friendly rather than sleek. Luckily, Xiaomi offers bundles like the creamy blue two-tone bezel and leather-style strap combo, which I found far more sophisticated. You can also grab nylon or fluoro rubber straps separately. Weighing in at 50g (including the strap) with a rugged aluminum alloy frame, it’s hefty but durable—no scratches or scuffs after weeks of wear, even with its slightly raised bezel offering minimal display protection. Plus, it’s water-resistant up to 5 ATM, so it can handle a swim or a sweaty workout.

Why It Matters: Whether you’re dressing up or keeping it casual, the Xiaomi Watch S4 adapts to your style—perfect for anyone who loves a personalized tech experience.

Stunning Display: Bright, Sharp, and Smooth

The 1.43-inch AMOLED display on the Xiaomi Watch S4 is a showstopper. With a 326 PPI resolution, text is crisp and legible, even the tiniest details. The 60Hz refresh rate keeps navigation smooth as you swipe through menus, matching the fluidity of top-tier smartwatches.

What impressed me most? The brightness. With auto-brightness that kicks in within a second, this screen shines even under harsh sunlight. The always-on display is subtle indoors (a bit too dim outdoors), but a quick wrist flick powers it up to reveal sharp contrasts and vivid colors. It’s a display that rivals the best in its class.

Pro Tip: If you’re often outdoors, this screen’s brightness ensures you won’t squint to check your stats.

Setup and Software: HyperOS Meets Mi Fitness

Pairing the Xiaomi Watch S4 with your smartphone is a breeze via the Mi Fitness app, available for free on the Google Play Store. Setup took me just a few minutes. The app lets you tweak watch faces, manage notifications, and input health stats for personalized tracking—think 24/7 heart rate monitoring, blood oxygen levels, stress tracking, and advanced sleep analysis.

Running on Xiaomi’s HyperOS, the watch offers a familiar yet distinct interface. Swipe up for customizable widget cards (e.g., health, weather, music), down for notifications, and left for watch faces. Each bezel set comes with a matching face, though my creamy blue one was oddly glitchy. No worries—the Mi Fitness app offers over 200 free watch faces, from sleek designs to cute ones (Mr. Wanko, anyone?). Simple faces upload in seconds, while complex ones take about a minute.

Heads-Up: Notifications are basic—you can read snippets but not reply. For more interaction, consider a Wear OS device like the OnePlus Watch 3.

Health and Fitness Tracking: Solid, But Not Perfect

The Xiaomi Watch S4 packs all the health essentials: step counting, heart rate monitoring, SpO2 tracking, stress levels, and sleep analysis. A 60-second checkup gives you a quick snapshot of your vitals—great for a casual wellness check. With over 150 sports modes (from dancing to obscure ones I couldn’t decipher), it’s got something for everyone. Dual-frequency GNSS tracking keeps tabs on outdoor runs or walks, though it’s not pinpoint accurate—I appeared to detour into buildings on one route.

My experience? Step counting during a boxing workout overestimated my movement, and heart rate readings occasionally spiked for no reason. Sleep tracking labeled me a “koala” (small, furry, and clingy—fair enough), but the cycle breakdown felt vague, and advice like “avoid books before bed” was unhelpful. Battery-draining 24/7 tracking is reliable for casual users, but serious athletes might want a Garmin for precision.

Takeaway: It’s a solid all-rounder for everyday fitness enthusiasts—not a pro-grade tracker.

Battery Life: A Week of Power

The 486mAh battery delivers big. With all features on—sleep tracking, continuous monitoring, everything—I got five full days of use. Dial back auto-workout detection, and you could stretch it to six or seven days. That’s a win over rivals like the OnePlus Watch 3 (four days max) and matches top Huawei models. Charging is fast too—fully drained to 100% in about an hour via a non-magnetic dock with a secure magnetic clasp.

Why You’ll Love It: Fewer charges mean more wear time—a game-changer for busy folks.

What’s Missing? Payments and App Support

Contactless payments? Spotty at best. In the UK, it supports Curve Card, but I hit errors trying to add mine—same as the last generation. App support is limited too—no marketplace to expand beyond preloaded options like weather, torch, and camera shutter. For deeper integration, Wear OS devices have the edge.

Xiaomi Watch S4 vs. OnePlus Watch 3: Which Wins?

The Xiaomi Watch S4 shines with its customizable design and longer battery life, but the OnePlus Watch 3 offers Wear OS flexibility—think message replies and broader app support. For casual users, Xiaomi’s value and style win. For tech-savvy folks, OnePlus might edge out.

Final Verdict: Should You Buy the Xiaomi Watch S4?

The Xiaomi Watch S4 is a stylish, affordable smartwatch with a gorgeous display, excellent battery life, and enough health tracking for most people. Its customizable bezels and straps make it feel fresh every time you switch things up. It’s not flawless—fitness tracking lacks precision, and payments are hit-or-miss—but for the price, it’s a compelling rival to the best smartwatches of 2025.

Who’s It For? Anyone seeking a versatile, long-lasting smartwatch without breaking the bank. If you’re a fitness buff or need robust app support, look elsewhere.

What do you think? Drop your thoughts below, and check out my reviews of the OnePlus Watch 3 and Huawei’s latest for more options. Happy smartwatch hunting!