OnePlus 9 Pro vs Samsung Galaxy S21 Ultra: Which do you prefer?


The market for premium flagships today is incredibly crowded. Among the manufacturers struggling to stand out from each other, there are two of the game’s biggest players vying for supremacy. The OnePlus 9 Pro and Samsung Galaxy S21 Ultra offer similar experiences at similar prices. While one continues to dominate in the photo space, the other relies on raw performance and software to get the job done. Are there enough differences to make them stand out from each other? Find out in Android Authority’s OnePlus 9 Pro vs Samsung Galaxy S21 Ultra hands-on comparison.

Design and display

The design of these two phones couldn’t be more different. The Samsung Galaxy S21 Ultra is heavier, has a matte finish in all color variants, and a larger camera bump. Both the body and screen are protected by the latest Gorilla Glass Victus, and the phone has an IP68 rating for water and dust resistance. The “Contour Cut” design of the camera feels deliberate and looks very dramatic in real life. Although the phone is gigantic, it doesn’t feel overwhelming and the overall weight gives a premium feel in the hand.


By comparison, the OnePlus 9 Pro is slimmer, has a glossy finish (unless you opt for the matte Stellar Black or Forest Green model), a smaller camera bump, and an alarm shutter. The body and screen are made of Gorilla Glass 5, and although there’s IP68 water and dust resistance rating, the device feels cheaper. This is partly due to the glossy finish and lighter weight of the phone, but I also prefer the camera design on the S21 Ultra. Though smaller, the OnePlus 9 Pro’s camera module feels more like an afterthought than a permanent fixture of the device.

The placement of the USB-C port, stereo speakers, and SIM card tray are almost identically placed. The volume button, however, is located on the left side of the OnePlus 9 Pro, as opposed to the right side on the Galaxy S21 Ultra. I’d give the S21 Ultra a slight edge here, as the button presses are a bit more tactile. The haptics on both devices are good, but the OnePlus 9 Pro comes away with a narrow victory – the vibrations are more precise and nuanced than on the S21 Ultra.

The Samsung Galaxy S21 Ultra feels more premium in the hand.

Both of these displays are impressive in their own right, with a QHD+ resolution screen, 120Hz adaptive refresh rate, and a notch for the camera. I’ll admit that I prefer the front camera placement on the OnePlus 9 Pro; that said, the S21 Ultra has a smaller cutout. Moreover, the Ultra’s screen is also slightly larger, measuring 6.81 inches compared to 6.7 inches on the 9 Pro. Comparing the side of the screen by side, I couldn’t recognize any noticeable differences in resolution or colors. The screen on the S21 Ultra is slightly less curved than the 9 Pro, but not to any appreciable degree.

Battery life

It’s not surprising that these big devices have big batteries. The Samsung Galaxy comes with a 5,000mAh cell, while the OnePlus 9 Pro comes with a 4,500mAh battery. On paper, this 500mAh difference doesn’t sound like much, but it’s a different story in reality. In the standard configuration (Full HD+ at adaptive 120 Hz), the OnePlus 9 Pro lasts just about a full day. In my tests, it usually needed a recharge around 10 pm. On the other hand, the S21 Ultra (again set to FHD+ and dynamic 120Hz) can last almost two days, with about 15% left towards the end of the second day. The S21 Ultra destroys the OnePlus 9 Pro when it comes to battery life performance.


The S21 Ultra destroys the OnePlus 9 Pro when it comes to battery life performance, but OnePlus’ fast charging smashes Samsung.

Where OnePlus beats the S21 Ultra, however, is in charging speeds. The 9 Pro comes with a 65W fast charger in the box, but the Galaxy S21 Ultra doesn’t come with any kind of included charger. This alone could be a deciding factor. The benefits for OnePlus don’t stop there, though. The 9 Pro charges at an incredible 65W, taking the phone from zero to 75% in just under 20 minutes. By comparison, the Galaxy S21 Ultra only charges at a rate of 25W, which makes for significantly longer charging times.

Again, the 9 Pro is a big winner when it comes to wireless charging. With OnePlus’ first-party 50W wireless charger, the 9 Pro can charge from 0% to 70% in just 30 minutes. Even with Samsung’s first-party wireless charger, the S21 Ultra can only charge at 15W wirelessly.

It’s interesting to see two sides of very different charging ideologies. Samsung chose the path of longer raw battery life, while OnePlus seems content to offer shorter battery life in exchange for faster charging. Whichever device you choose, there will, unfortunately, be a trade-off.

Performance and user interface

The raw power on the Galaxy S21 Ultra and OnePlus 9 Pro is almost identical, as both phones come with the latest Snapdragon 888 processor. The 9 Pro has options for 8GB and 12GB of RAM, while the S21 Ultra starts with a base of 12GB and goes up to a full 16GB for the top model. In our test, the Galaxy S21 Ultra scored 5,022 in Geekbench 4 single-core and 13,915 in multi-core. For comparison, the OnePlus 9 Pro scored 5,036 and 14,371 respectively. We also ran our custom Speed Test G-benchmark, and the 9 Pro ran away with a narrow victory in the timed test with a time of one minute and 15 seconds compared to the S21 Ultra’s one minute and 19 seconds. What this means for your everyday life is that both phones will provide a smooth experience across the board. Yes, the 9 Pro is technically more powerful than the Galaxy S21 Ultra, but users won’t experience this marginal difference in speed.


Gaming is no different, with both phones performing impressively in their own right. I didn’t notice any significant difference in games like PUBG Mobile or Asphalt 9. The adaptive 120 Hz comes into its own in both devices, as games at 60fps were smooth without noticeable hangs or stutters. I will say that the 9 Pro remained a little cooler to the touch when playing for extended periods, but again the difference is negligible.

Another significant difference is the user interface. Both devices run Android 11 but come with different skins. The OnePlus 9 Pro runs Oxygen OS 11, which I found far cleaner than the One UI 3 running on the Samsung Galaxy S21 Ultra. It might come as a surprise to some, but the 9 Pro also comes with less bloatware than the Galaxy S21 Ultra. Apart from the aesthetic differences, the functionality of both skins is almost the same. From a user perspective, I can add that the Oxygen OS is a bit easier to navigate, but again that’s my personal opinion. It’s easy to find settings, and both default launchers have native Google integration with the Google Discover feed on the far left home screen. You can read more about the differences between Oxygen OS and One UI in our in-depth dive linked above.


Cameras have traditionally been OnePlus’ Achilles heel, with Samsung taking an easy win in all Vs match-ups. This time, however, it’s closer than ever. OnePlus has partnered with Hasselblad in an attempt to solve some of its long-standing camera problems. This new change has proven to be quite successful, but as you’ll find out, the Samsung Galaxy 21 Ultra fares slightly better than the OnePlus 9 Pro in most metrics.

Both of these devices handle dynamic range, white balance, detail, and color well. However, the OnePlus 9 Pro seems to produce slightly more detailed images compared to the Galaxy S21 Ultra. On paper, you might think that the S21 Ultra would beat the 9 Pro because of the larger 108MP wide-angle camera. For comparison, the OnePlus 9 Pro uses a 48MP primary camera. However, both produce 12MP images by default (due to pixel binning) and the result shows a very comparable detail capture. As I’ve said before, specs don’t mean everything, and the 9 Pro is an excellent example of this. That said, I think the difference comes down to software processing. The 9 Pro tends to over-sharpen images, giving the effect of a more detailed photo, whereas the Galaxy S21 Ultra‘s detail is on par, but the software processing softens the image. Either way, this is the closest we’ve seen OnePlus come when it comes to camera performance.


The S21 Ultra still produces more saturated, punchy images and brighter photos. As we mentioned in our full review, thanks to the partnership with Hasselblad, OnePlus has improved its color processing in this generation, which is on the realistic side of things. The images produced are flatter with less contrast and saturation. Some might see this as a drawback, but it gives you some extra flexibility to edit the images in post-processing. I preferred the overall look of the S21 Ultra’s color gamut over the 9 Pro, but that will come down to personal preference. If you like punchier, brighter images, then the Galaxy S21 Ultra might be the camera phone for you.

HDR performance on the OnePlus 9 Pro is not as good as on the Galaxy S21 Ultra. In most cases, the S21 Ultra retains more detail in shadows and highlights, resulting in a slightly more natural-looking HDR image. This is especially noticeable in lower-light indoor shots, as the 9 Pro produces some oversaturated scenes. In daylight scenarios, however, the 9 Pro still competes but tends to reduce highlights and lift shadows a bit more. The resulting image is a bit flatter than the S21 Ultra, but not at all unpleasant.

The wide-angle lenses on both these phones are good. The S21 Ultra, however, tends to produce a slightly sharper image with a higher dynamic range. It also produces a more accurate white balance, and images are brighter and more saturated. The Galaxy S21 takes the win here, but by a small margin.

Finally, the telephoto and selfie cameras are both very close, but again the Galaxy S21 Ultra produces brighter, sharper, and less noisy images. This is especially important in the telephoto lens, considering the S21 Ultra has 10x optical zoom compared to OnePlus’ 3x. Still, even at 3x, the S21 Ultra produces far sharper and cleaner images.

In general, the Samsung Galaxy S21 Ultra performs better in low light. Dynamic range and white balance are a bit more accurate than the OnePlus 9 Pro. That said, the 9 Pro again seems to retain more detail in highlights and shadows. Both devices produce incredibly dense images in low light, but I still preferred the more saturated images that come out of the S21 Ultra.

OnePlus 9 Pro vs Samsung Galaxy S21 Ultra: the verdict

Both devices are incredibly good. The specs compete on paper and in real life, meaning it’s never been so hard to choose one of these premium flagships over another. Moreover, the main cameras on both these devices perform so closely that I don’t think it’s a metric to choose one over the other. That said, the Samsung Galaxy S21 Ultra offers a more premium experience, both in design and battery life, albeit at a much higher price. For power users with money to spare, the extra flexibility offered by the longer battery life could be a deciding factor.

On the other hand, the OnePlus 9 Pro has insanely fast charge times, a minimalist design, and competitive cameras – all for 200 crowns less for the base model. Therefore, budget-conscious consumers might find the OnePlus 9 Pro more attractive.

Bottom line, if you want a smoother user interface and incredibly fast charging times, go for the OnePlus 9 Pro, but if longer battery life, overall camera versatility, and a more premium design are your cup of tea, the Galaxy S21 Ultra is a clear choice.


              OnePlus 9 Pro Samsung Galaxy S21 Ultra
Display 6.7-inch curved LTPO AMOLED
20.1:9 aspect ratio
3,216 x 1,440 at 525ppi
120Hz refresh rate (adaptive)
6.8-inch Dynamic AMOLED
Curved WQHD+
3,200 x 1,440 at 515ppi
Adaptive 120Hz refresh rate
Processor Qualcomm Snapdragon 888 Qualcomm Snapdragon 888 or Samsung Exynos 2100
RAM 8 or 12GB 12 or 16GB
Storage 128 or 256GB
No external storage
128, 256, or 512GB
No external storage
Power 4,500mAh battery

Warp Charge 65T
65W charger in box

Warp Charge 50 Wireless
10V/6.5A, 20V/3.25A
Output: 50W (with prop. charging stand)

5,000mAh battery

Fast wired and wireless charging

Connectivity 5G support
Wi-Fi 6 support
2×2 MIMO
Wi-Fi 802.11 a/b/g/n/ac/ax
NFC support
Bluetooth 5.2
5G support
Wi-Fi 6E support
NFC support
Bluetooth 5.0
Cameras Rear:
– 48MP main (Sony IMX789)
1/1.43-inch sensor
1.12μm/46MP or 2.24μm/12MP
ƒ/1.8, EIS, OIS
– 50MP ultra-wide (Sony IMX766)
1/1.56-inch sensor
– 8MP telephoto
1.0μm, ƒ/2.4
– 2MP monochrome

– 16MP single (Sony IMX471)
1.0μm with EIS
ƒ/2.4, fixed focus

– Wide-angle: 108MP, ƒ/1.8, 0.8µm with OIS and phase-detection AF
– Telephoto: 10MP, ƒ/2.4, 1.22µm with OIS, dual-pixel AF, and 3x optical zoom
– Telephoto: 10MP, ƒ/4.9, 1.22µm with OIS, dual-pixel AF, and 10x optical zoom
– Ultra-wide: 12MP, ƒ/2.2, 1.4µm with dual-pixel AF and a 120-degree FoV
– Laser AF sensor

10x optical zoom
100x “Space Zoom”

– 40MP, ƒ/2.2, 0.7µm, with phase-detection AF

Software Android 11
Oxygen OS 11
Android 11
One UI 3.1
Dimensions and weight Global:
163.2 x 73.6 x 8.7mm
75.6 x 165.1 x 8.9mm
Colors Morning Mist, Forest Green, Stellar
128 GB in Phantom Silver and Phantom Black

256 and 512GB in Phantom Black

Other colors: Phantom Titanium, Phantom Navy, and Phantom Brown


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