Xiaomi 15 Ultra vs. Samsung Galaxy S25 Ultra: Rewriting the status quo

Xiaomi 15 Ultra vs. Samsung Galaxy S25 Ultra: Design and display

Xiaomi made subtle changes to the design of the Xiaomi 15 Ultra, and the result is a device that's quite striking. While I'm using the white model, the two-tone variant of the device is styled to look like retro cameras, and it is definitely the one to get. The aesthetic combined with beveled sides and rounded edges make it great to hold and use, and even though it's heavy at 226g, I didn't notice that heft in regular use.

The phone is built to last; Xiaomi is using a custom glass solution at the front, and the back is made out of a resilient material that weathers tumbles with ease. I didn't use a case with the phone, and after a month and a half of extensive use with travel to three countries, the 15 Ultra still looks pristine.

Samsung chose to go with a similar design, but the Galaxy S25 Ultra has rounded edges, and that makes it a little easier to hold. Outside of that, it is still a giant slab of a phone, and while the design is familiar, it doesn't quite stand out anywhere as much as Xiaomi's device. That said, the use of a titanium mid-frame gives the device greater rigidity.

Both devices get IP68 ingress protection, and I didn't see any issues in this regard. They both use ultrasonic biometric sensors, and the one on the Xiaomi 15 Ultra is great to use — it's fast to authenticate and is ideally located.

Xiaomi once again went with a 6.73-inch AMOLED panel, but it has much better brightness this time around. While the phone doesn't get as bright as the Vivo X200 Pro or the Pixel 9 Pro XL, it is noticeably brighter than the S25 Ultra both indoors and outdoors, and that's what ultimately matters. Xiaomi once again did a fantastic job tuning the panel out of the box, and you get vibrant colors and excellent contrast with plenty of adjustability.

To Samsung's credit, the brand did a good job slotting in a bigger 6.9-inch panel into the S25 Ultra, and it also has good color vibrancy. The anti-reflective coating on the panel makes it well-suited to outdoor use, and although it doesn't get as bright as its rivals, there are no issues viewing the panel under harsh sunlight.

Both phones do a great job with media playback and gaming, and they have good built-in audio. The Xiaomi 15 Ultra wins out thanks to a better in-hand feel and brighter panel, but the S25 Ultra gets a lot right — even though it doesn't quite have the same great feel.

Xiaomi 15 Ultra vs. Samsung Galaxy S25 Ultra: Hardware

There isn't anything missing on the hardware side of things, with both devices powered by the same Qualcomm silicon. Of course, Samsung once again gets a higher-binned version going up to 4.47GHz — while the standard platform in the Xiaomi goes up to 4.32GHz — but there's no noticeable difference between the two in daily use. Both phones are among the fastest available today, and they run demanding games effortlessly.

One point of contention with the Xiaomi 15 Ultra is that it tends to overheat during extended gaming sessions; it gets hotter than most other 2025 phones I used, but the side effect is that it doesn't have any issues with throttling. The Galaxy S25 Ultra doesn't have any issues in this regard, and it continues to be a standout choice.

The S25 Ultra base model comes with 12GB of RAM and 256GB of storage, but Xiaomi is selling the 16GB/512GB as the standard globally, and it uses the latest UFS 4.1 storage module instead of the UFS 4.0 that's on Samsung. Similarly, the Xiaomi 15 Ultra comes with a Bluetooth 6.0 radio, and it is the only device I used until now to have it. I didn't see any issues with connectivity or while making calls, and the Xiaomi 15 Ultra has a fantastic vibration motor.

Xiaomi has a clear advantage with battery life; the 15 Ultra has a 5410mAh battery outside China, and it easily lasts over a day. The S25 Ultra also lasts a day, but the 5000mAh battery doesn't quite last as long as Xiaomi's device. Then there's the charging situation, with Samsung once again limiting its phone to 45W. Xiaomi retained 90W charging on the 15 Ultra, and it takes less than half as long to charge the battery as the S25 Ultra while lasting longer.

Xiaomi 15 Ultra vs. Samsung Galaxy S25 Ultra: Cameras

There's no contest — the Xiaomi 15 Ultra has the better camera package overall. The software I'm testing still has a few issues with HDR blooming, and as such, images aren't consistent all the time. Even then, the caliber of shots produced by the Xiaomi 15 Ultra is leagues better than the S25 Ultra — Samsung really needs to overhaul its strategy in this area.

The 15 Ultra has a 1-inch main camera with a Sony LYT-900 imaging module, and this year, it's joined by a 200MP Samsung HP9 tele lens that goes up to 4.3x, and a secondary 50MP tele that shoots at 3x. A 50MP wide-angle lens rounds out the cameras at the back, and this is the strongest set of cameras until the Vivo X200 Ultra or Find X8 Ultra debut sometime later this year.

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Samsung is using the same 200MP main camera as last year, and while the S25 Ultra gets a new 50MP wide lens, it doesn't quite manage to stand out anywhere as much as its Chinese rival. The Xiaomi 15 Ultra wins out when it comes to dynamic range, color vibrancy, and detail rendition. Portraits in particular are stunning on the 15 Ultra, and you just don't get the same kind of segmentation or quality out of the S25 Ultra, and that's a real limitation.

Xiaomi 15 Ultra vs. Samsung Galaxy S25 Ultra: Software

Both phones run Android 15 out of the box, and Samsung has the definite edge when it comes to software updates. The S25 Ultra will get seven Android updates, with the Xiaomi 15 Ultra limited to four. Samsung also does a much better job rolling out updates on time, and although the S24 Ultra is yet to make the switch to Android 15, there's a good bet that the device will get the stable build before the Xiaomi 14 Ultra — Xiaomi just doesn't roll out timely updates.

The software itself is unchanged on both phones, so if you've used a Xiaomi or Samsung device in the past, you'll be immediately familiar with what's on offer. Samsung's push into AI with Galaxy AI gives the S25 Ultra an extensive toolkit in this area, and whether it's image generation or editing, writing assistance, transcribing, or real-time translations, the device does a great job. I used the built-in audio transcribing utility on the Xiaomi 15 Ultra to good effect as well, but the phone doesn't have quite as many features as the S25 Ultra at least when it comes to the AI side of things.

Outside of that, there isn't much to talk about. The Xiaomi 15 Ultra has better fluidity than the S25 Ultra, and it doesn't have quite as many annoyances as earlier iterations of the software. Both skins need a visual overhaul, but they deliver extensive customizability.

Xiaomi 15 Ultra vs. Samsung Galaxy S25 Ultra: Which should you buy?

Xiaomi didn't have to do too much to make the Xiaomi 15 Ultra stand out, and the addition of a new 200MP lens at the back alongside the usual design and hardware changes make the phone a real powerhouse. It has the best camera package of any 2025 device yet, and while there are some inconsistencies with HDR imagery, it takes fantastic photos and videos in just about any situation.

The design is better this time around, the battery lasts longer than last year, the AMOLED panel is brighter, and the UI is better. The phone runs hotter than its immediate rivals, but it doesn't have any shortcomings when it comes to gaming as such outside of the heat, and I didn't see any issues with connectivity.

Ultimately, the biggest issue with the Xiaomi 15 Ultra is availability; Xiaomi still doesn't sell phones in the U.S., and that makes it annoying to get a hold of the device in region. But with the phone selling in India, the U.K., and key western markets, it is easier to buy than the Find X8 Pro and Vivo X200 Pro, and that's a big deal in and of itself.

Coming to Samsung, the Galaxy S25 Ultra just doesn't do enough to push the needle, and I'm not convinced that it's worth the cash. It is still a great phone in its own right, and if you're on an older Samsung device and want to make the switch, it is a viable choice. That said, the Xiaomi 15 Ultra does a better job in just about every area other than long-term update guarantee, and if you don't have any allegiance to Samsung, I highly recommend switching to Xiaomi — you'll love what this phone can do in daily use.