The flagship Android smartphone market is as competitive as ever, and OnePlus 9 Pro vs Galaxy S21 Ultra comparisons are a hot topic of conversation. This year's Galaxy S21 Ultra starts at $200 cheaper than last year's S20 Ultra and has even more features than the previous model. Meanwhile, OnePlus has continued to raise prices on its phones every year, and the current OnePlus 9 series is no exception. The OnePlus 9 Pro starts at $1,069 — more expensive than many other phones, but still over $100 cheaper than the Galaxy S21 Ultra (when the Ultra isn't on sale).

The OnePlus 9 Pro and Galaxy S21 Ultra are some of the best flagship Android phones available today, but which one is better? In this guide, we'll give you all the facts and comparisons you need to make an informed purchase. We also have a review for the OnePlus 9's camera, which is similar (though not identical) to the setup found on the OnePlus 9 Pro.

OnePlus 9 Pro & Galaxy S21 Ultra Specifications

OnePlus 9 Pro Forums ||| Samsung Galaxy S21 Ultra Forums

Design and Hardware: Nearly identical, but not the same!

The Galaxy S21 Ultra and OnePlus 9 Pro have a similar design and build. Both phones are massive slabs of aluminum and glass, with curved ("2.5D") screens on the front and multi-camera setups on the back. The Galaxy S21 Ultra is the larger of the two with its 6.8-inch display, but the OnePlus 9 Pro is close behind with a 6.7-inch screen. Some OnePlus 9 Pro color variants have a glossy finish on the glass, while all the Galaxy S21 Ultra variants have a matte finish. The camera modules on both devices also gives them their own defining individuality.

The displays are nearly the same size, and they're also similar in functionality. Both phones have high-quality AMOLED panels, with vibrant colors and deep blacks, as well as a maximum refresh rate of 120Hz. That means everything from gaming to scrolling through Twitter will be buttery smooth. Both phones also have fingerprint sensors under the display.

The rest of the internal hardware is also similar. The Galaxy S21 Ultra and OnePlus 9 Pro both start with 128GB of internal storage, but with no microSD card slot. The OnePlus 9 Pro can be configured with up to 12GB RAM and 256GB storage, while the highest-tier Galaxy S21 Ultra has 16GB RAM and 512GB storage.

There is one important distinction between the two phones: the System-on-a-Chip (SoC), which includes the CPU and GPU. No matter where you buy it, the OnePlus 9 Pro is powered by a Snapdragon 888 chipset. However, the SoC in the Galaxy S21 Ultra varies by location — it has a Snapdragon 888 in the United States and a few other regions and Samsung's own Exynos 2100 chipset everywhere else. The two chipsets are close enough in real-world performance that the difference doesn't really matter, but it's worth noting here.

The Galaxy S21 Ultra and OnePlus 9 Pro both have all-day battery life. The former has a 5,000 battery with up to 25W fast charging, while the latter has a slightly smaller 4,500mAh battery with faster 65W charging. Both phones can charge wirelessly at 15W using standard Qi pads (and the OnePlus 9 Pro can reach 65W with OnePlus' $70 dock), and they can act as a slow wireless charging pad for other devices.

The Galaxy S21 Ultra has one more hardware trick: It's compatible with Samsung's S Pen stylus. You can use the pen as a pointer (helpful if you're frequently wearing gloves), jot down hand-written notes with apps like Microsoft OneNote or MyScript Nebo, or just have fun doodling. However, you can't store the S Pen inside the phone like you can with any Galaxy Note device. You also don't get the S Pen included with the Galaxy S21 Ultra as it's sold separately.

The rest of the specifications are more or less the same across both phones. They share IP68 water/dust resistance, 4G LTE and 5G support, dual stereo speakers, and a USB Type-C port. Neither phone has a headphone jack, nor do they include an adapter in the box to use 3.5mm wired headphones/earbuds.

Cameras: Both are excellent, but Galaxy S21 Ultra is the zoom champion

The Galaxy S21 Ultra has four rear cameras: a 108MP primary lens, a 12MP ultra-wide, a 10MP telephoto, and another 10MP telephoto. The phone switches between the two telephoto cameras depending on how much zoom is needed — one of them is capable of 3x, while the other is 10x. There's also a 40MP selfie camera, and all lenses are capable of 4K/60FPS video capture.

Meanwhile, the OnePlus 9 Pro has three rear cameras, plus a 2MP monochrome sensor that helps the other lenses. There's a 48MP main camera, a 50MP ultra-wide, and an 8MP telephoto. 4K/120FPS video is supported, as well as 8K at 30FPS. You'll run out of storage fast if you use the latter option, though.

So how do the photos look? Well, it's a close race between the two phones. Photos from the primary rear lens on either device are high-quality, though I slightly prefer the OnePlus 9 Pro. The Galaxy S21 Ultra, like most other Samsung phones, has a tendency to increase the color saturation and brightness to unnatural levels. In the photos with leaves and grass, the green color is more neon-like than the color that appears in real life. I personally prefer the more life-like colors from the OnePlus 9 Pro's camera, but both phones perform well here, including in low-light conditions.

Both phones are capable of 3x zoom without cropping the image, and there's not much of a difference between the two devices here. However, once you go past 3x zoom, the race is absolutely one-sided. The OnePlus 9 Pro's telephoto lens is only capable of 3.3x optical zoom, while the Galaxy S21 Ultra can reach 10x optical zoom. In situations where you need to capture something from far away, the Galaxy S21 Ultra is the clear winner.

Finally, both phones also have wide-angle lenses, and the results are excellent on either device. No matter which phone you go with, capturing wide shots won't be a problem. One thing to note is the noticeably less edge distortion on the wide-angle lens on the OnePlus 9 Pro, which can be something that some users appreciate.

In summary, both phones are close enough in photo quality that most people would be happy with either device. The OnePlus 9 Pro comes out slightly ahead if you prefer life-like color balance and brightness, though if you frequently zoom in farther than 3x, the Galaxy S21 Ultra is the better choice.

Final Thoughts

The Galaxy S21 Ultra and OnePlus 9 Pro are alike in almost every way that matters. Both phones have speedy internal hardware, an all-day battery, excellent cameras, large screens, and so on. Neither device is better than the other in a significant way, but there are smaller differences that are important to some people. The Galaxy S21 Ultra can be configured with more storage and RAM than the OnePlus 9 Pro, so if you never want to delete anything ever, Samsung's phone might be the better option. The physical alert slider on the OnePlus 9 Pro, which isn't available on any Samsung phones, is also a selling point for some.

The software experience can also be a determining factor. Both phones ship with Android 11, with each company's 'skin' on top that adds extra features — OxygenOS on the OnePlus 9 Pro, and One UI on the Galaxy S21 Ultra. OxygenOS is generally clean and intuitive, though there have been reports of software bugs on the OnePlus 9 series, including the same issues with missed push notifications that have affected other OnePlus phones in the past.

Samsung's One UI 3.1 (also based on Android 11) is a bit more feature-packed than OxygenOS 11, but it also has more annoying advertisements than you'd usually see from the system services on a OnePlus phone. Samsung DeX, a feature where you can connect your phone to a monitor/TV/PC and use your apps in a desktop environment, is popular with some Samsung fans and doesn't have a comparable equivalent on OxygenOS.

The OnePlus 9 Pro starts at $1,069 for 12GB RAM and 256GB storage, though a cheaper 8GB RAM/128GB storage option is available in some countries (like India). The Galaxy S21 Ultra starts at $1,200 for 8GB RAM and 128GB storage, with other configurations available with 12GB/256GB and 16GB/512GB, depending on your region. However, Samsung phones go on sale frequently, and the base model of the Galaxy S21 Ultra has dropped below $1,000 a few times already.