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OnePlus 9 Pro vs. Samsung Galaxy S21 Ultra: Which Android phone wins?

OnePlus 9 Pro vs. Samsung Galaxy S21 Ultra
(Image credit: Tom's Guide)

The Samsung Galaxy S21 Ultra and the OnePlus 9 Pro are the two best Android phones around right now. But which one can claim the top spot as the best Android phone?

Since it arrived earlier this year, the Samsung Galaxy S21 Ultra has been the ultimate example of all the features and capabilities Samsung can bring to a smartphone. But there's a new big-screen challenger.

Anything the Galaxy S21 Ultra can do, the new OnePlus 9 Pro claims to be able to do it better. Give users a large display with a fast refresh rate? The OnePlus 9 Pro can do that. Last a long time on a charge? No sweat, OnePlus says. Even cameras — a long-standing issue with OnePlus phones — have received a lot of attention with the OnePlus 9 Pro.

Can OnePlus unseat Samsung from the Android phone throne? To find out, we conducted a OnePlus 9 Pro vs. Samsung Galaxy S21 Ultra face-off. This smartphone battle couldn't be closer.

OnePlus 9 Pro vs. Samsung Galaxy S21 Ultra

OnePlus 9 ProSamsung Galaxy S21 Ultra
Starting price$969$1,199
Screen size6.7-inch AMOLED (3168 x 1440)6.8 inches AMOLED (3200 x 1400)
Refresh rate1Hz to 120Hz10Hz to 120Hz
CPUSnapdragon 888Snapdragon 888
RAM8GB, 12GB12GB, 16GB
Storage128GB, 256GB128GB, 256GB, 512GB
Rear cameras48MP wide (f/1.8), 50MP ultrawide (f/2.2), 8MP telephoto (3x zoom, f/2.4), monochrome lens108MP wide (f/1.8), 12MP ultrawide (f/2.2), 10MP telephoto (3x zoom, f/2.4), 10MP telephoto (10x zoom, f/4.9), laser AF sensor
Front cameras16MP (f/2.4)40MP (f/2.2)
Battery size4,500 mAh5,000 mAh
Battery life (Hrs: Mins)10:38 (60Hz); 10:40 (adaptive)11:25 (60Hz), 10:07 (adaptive)
Size6.4 x 2.9 x 0.34 inches6.5 x 2.97 x 0.35 inches
Weight6.9 ounces8.08 ounces

OnePlus 9 Pro vs. Samsung Galaxy S21 Ultra price and availability

Outside of Samsung's folding phones, the Galaxy S21 Ultra is the most expensive Samsung device you can buy, with a starting price of $1,199 for the 128GB model. If you want to increase that storage to 256GB, you'll pay an extra $50, while the ultimate S21 Ultra — which includes 512GB of storage plus 16GB of RAM — costs $1,379. That's still cheaper than last year's base model Galaxy S20 Ultra, which debuted at $1,399.

Even so, the OnePlus 9 Pro costs less than the Galaxy S21 Ultra. OnePlus' entry-level model, with 8GB of memory and the same 128GB of storage, costs $969. Upgrading to a 256GB model with 12GB of RAM will cost you $1,069.

It's easier to get a Galaxy S21 Ultra, which is available from every major U.S. carrier as well as from Samsung. T-Mobile is the only carrier selling the OnePlus 9 Pro in the U.S., though the phone is also available through OnePlus and retailers like Amazon, Best Buy and B&H.

Winner: OnePlus 9 Pro

OnePlus 9 Pro vs. Samsung Galaxy S21 Ultra design

Save for the different company logos on the back of each phone, the OnePlus 9 Pro and Samsung Galaxy S21 Ultra look a lot alike. You'll find a pair of phones with subtly curved displays — the OnePlus 9 Pro's curve is far less dramatic than last year's OnePlus 8 Pro — without a whole lot in the way of bezels on the top and bottom of the screen. Flip the phones over, and you'll see rectangular camera arrays in the upper left corner; the camera bump on the Galaxy S21 Ultra looks a little less prominent thanks to a contour cut design in which the array blends into the side of the phone.

oneplus 9 pro and samsung galaxy S21 ultra face down

(Image credit: Tom's Guide)

The OnePlus 9 Pro is probably the easier of the two phones to tote around, as it's slightly shorter and not as wide as the 6.5 x 2.97 x 0.35-inch Galaxy S21 Ultra. Samsung's phone weighs in at 8.08 ounces, more than an ounce heavier than the 6.9-ounce OnePlus 9 Pro.

One advantage Samsung usually lords over OnePlus phones has disappeared. The Galaxy S21 Ultra has an IP68 rating for water resistance, but so does the OnePlus 9 Pro. That's something OnePlus usually skips on its flagships. (The cheaper OnePlus 9, for example, doesn't have such a rating if you buy the unlocked version.)

oneplus 9 pro and samsung galaxy S21 ultra face up in hand

(Image credit: Tom's Guide)

 the Galaxy S21 Ultra comes in pretty standard Phantom Black and Phantom Silver colors. Buy the phone directly through Samsung, though, and you can branch out into Phantom Navy, Phantom Titanium and Phantom Brown options. And of course, you've got the best Galaxy S21 Ultra cases if you want a different look and added protection and features on top.

OnePlus takes more of a chance with color than Samsung does, as the OnePlus 9 Pro has just two color options — Morning Mist and Pine Green. The former offers a nice mirror-like sheen, but one that can attract fingerprints. Also in some markets, OnePlus locks these colors depending on which spec you're buying, which might be frustrating for some users.

Winner: OnePlus 9 Pro

OnePlus 9 Pro vs. Samsung Galaxy S21 Ultra display

OnePlus 9 Pro and Samsung Galaxy S21 Ultra stood beside each other

(Image credit: Tom's Guide)

It's a battle of dynamically refreshing displays in a OnePlus 9 Pro vs. Galaxy S21 Ultra showdown. Samsung helped introduce this trend, first with the Galaxy Note 20 Ultra, and now with the S21 Ultra. That phone's massive 6.8-inch AMOLED panel adjusts the speed at which refreshes, depending on what you're doing. Activities like scrolling that benefit from a faster refresh rate can make the display scale up to the maximum 120Hz speed, while more static activities make the S21 Ultra's screen drop down to 10Hz.

But the OnePlus 9 Pro features the same LTPO technology in its 6.7-inch display. The refresh range is even wider here than on the Galaxy S21 Ultra, with the OnePlus 9 Pro capable of scaling down to 1Hz.

OnePlus 9 Pro front three-quarter view

OnePlus 9 Pro (Image credit: Tom's Guide)

The OnePlus 9 captures more of the DCI-P3 color gamut — 84.9% to the S21 Ultra's 81.4%. Those colors are more accurate, too, given the OnePlus 9 Pro's Delta-E rating of 0.20 versus a 0.3 rating for the S21 Ultra. (Numbers closer to zero are more accurate.)

Galaxy S21 Ultra playing Schitt's Creek

Samsung Galaxy S21 Ultra (Image credit: Future)

Where the Galaxy S21 Ultra regains an edge over the OnePlus 9 Pro is in just how bright its screen gets. Measuring 722 nits, the OnePlus 9 Pro is far from dim. But the Galaxy S21 Ultra is even brighter at 821 nits, ensuring that you'll see all of that display even when you're in bright sunlight.

Winner: Galaxy S21 Ultra

OnePlus 9 Pro vs. Samsung Galaxy S21 Ultra cameras

Past camera competitions involving Samsung and OnePlus haven't been much of a fight. Samsung flagships tend to regularly rate among the best camera phones available, while OnePlus' cameras have struggled to keep up. But the OnePlus 9 Pro introduces a new twist to this long-standing rivalry, with OnePlus teaming up with photo specialist Hasselblad to improve its cameras.

This involves more than just stamping Hasselblad's name next to the rear lenses on the OnePlus 9 Pro (though that branding is certainly there). Instead, the OnePlus 9 Pro benefits from improvements to color calibration that OnePlus and Hasselblad have worked on together.

OnePlus 9 Pro and Samsung Galaxy S21 Ultra held together

(Image credit: Tom's Guide)

Going up against the cameras on the Galaxy S21 Ultra certainly requires an extra effort. Samsung's phone features four rear shooters — a massive 108MP main sensor, along with a 12MP ultrawide angle lens and a pair of 10MP telephoto lenses offering respective zooms of 3x and 10x. In contrast, there's a single 8MP telephoto lens on the OnePlus 9 Pro with a 3x zoom of its own. You also get a 48MP main camera and 50MP ultrawide angle lens as well as a dedicated monochrome camera that, frankly, doesn't add much to the picture.

We immediately see the benefit of OnePlus' focus on improved color with this photo of a fruit and vegetable stand. The OnePlus 9 Pro's shot is vibrant, but still realistic, while the Galaxy S21 Ultra over-saturates the green peppers, which also appear slightly out of focus.

Moving outside for a close-up shot of a flower, the S21 Ultra redeems itself. In the S21 Ultra photo, the flower is in sharp focus, and the S21 Ultra picks up small details like beads of water on the leaf. The OnePlus 9 Pro photo isn't bad, but those details don't really stand out, as the green leaves in the background seem to blend together.

Low light photos were one area where we really spotted inconsistencies when testing the OnePlus 9 Pro and that's continued in the OnePlus 9 Pro vs. Samsung Galaxy S21 Ultra face-off. The streetlamp in the OnePlus shot is over-exposed and the night sky around looks fuzzy as a result. Things are placed into much sharper relief in the Galaxy S21 Ultra's photo where the lamps don't blow out details all around them, and the yellow hues from the street lights stretch out across the grass.

Testing out the portrait features of the respective camera phones, it's something of a tossup. My colleague Mark stands out a little better against the background in the OnePlus 9 Pro shot, but apart from his bright blue shirt, there's a hazy cast to the background. OnePlus also seemed to smooth things out in a way that the S21 Ultra did not — you can see the folds and wrinkles in his t-shirt more distinctly in that photo. The color cast looks more natural in the Samsung shot, too.

For the OnePlus 9 Pro's ultrawide angle shooter, OnePlus used a freeform lens that's supposed to remove some of the distortion found around the edges of wide-angle shots. I can't really say that's in evidence in this particular shot of a lake, but I have seen improved ultrawide shot comparisons elsewhere that demonstrate the OnePlus 9 Pro's skill in keeping that bend out of photos. I just think the OnePlus 9 Pro does a better job keeping the entire image in focus — see how the dock looks in both shots — even if the bluer sky in the S21 Ultra photo is more attractive.

We maxed out the zoom on both cameras to 30x to see which telephoto lens you'd trust. Neither photo is really a standout, but the Galaxy S21 Ultra handles colors better — that hazy cast has returned to the OnePlus shot — and everything's in a little better focus thanks to the Zoom Lock feature that can steady your shot from far away. 

Overall, I think the Galaxy S21 Ultra comes out ahead in this camera face-off, though it's much closer than previous OnePlus vs. Samsung showdowns. The OnePlus 9 Pro features the best cameras OnePlus has put in its phones, and that's on display here.

Winner: Samsung Galaxy S21 Ultra

OnePlus 9 Pro vs. Samsung Galaxy S21 Ultra performance and 5G

"Ultra" does not necessarily mean "ultimate." While the Galaxy S21 Ultra performs very well on benchmark tests, it doesn't noticeably outperform the OnePlus 9 Pro. In fact, on some tests, the OnePlus 9 turns in the better numbers.

That's not really a surprise, as both phones are powered by a Snapdragon 888 system-on-chip, the best silicon Qualcomm has to offer these days. Samsung augments that processing platform with either 12GB or 16GB of RAM. OnePlus 9 Pro users get either 8GB or 12GB.

OnePlus 9 Pro and Samsung Galaxy S21 Ultra face down on mossy ground

(Image credit: Tom's Guide)

On Geekbench 5, the two phones can match each other stride for stride in the single core test, as the Galaxy S21 Ultra turned in a 1,123 score to the OnePlus 9 Pro's 1,126. The OnePlus handset pulls ahead withe multicore performance, reaching 3,685 on Geekbench to the S21 Ultra's 3,400 result.

Graphics are also evenly matched, based on the results of 3D Mark's Wild Life Unlimited Test. Here, the S21 Ultra turned in a 34.4 frames per second score, essentially tying the OnePlus 9 Pro's 34.5 FPS result. In other words, you're essentially getting the same performance from either phone — a mark in the OnePlus 9 Pro's favor since it's nearly $250 cheaper than its Samsung rival.

Galaxy S21 Ultra undergoing an Ookla 5G speedtest

Samsung Galaxy S21 Ultra (Image credit: Future)

However, the Galaxy S21 Ultra holds an edge over the OnePlus 9 Pro when it comes to 5G connectivity. You can use Samsung's phone on any 5G network in the U.S. The OnePlus 9 Pro is a little more restricted. It works perfectly fine with T-Mobile's 5G, but not at all with AT&T 5G

After this OnePlus 9 Pro vs. Samsung Galaxy S21 Ultra face-off first appeared, Verizon and OnePlus announced that the OnePlus 9 Pro will work on Verizon 5G — both the slower nationwide network as well as the fast Ultra Wideband 5G Verizon has launched in more than 60 cities. The cheaper OnePlus 9 won't work with Ultra Wideband, Verizon says.

Winner: Samsung Galaxy S21 Ultra

OnePlus 9 Pro vs. Samsung Galaxy S21 Ultra battery and charging

The Galaxy S21 Ultra would seem to have an edge in battery life, given that it's powered by a 5,000 mAh battery to the 4,500 mAh power pack inside the OnePlus 9 Pro. And to be sure, the S21 Ultra lasted a long time on our battery test, in which we have phones surf the web continuously over cellular (5G in this case) until they run out of power. With a time of 11 hours and 25 minutes, the Galaxy S21 Ultra lasts long enough to land on our best phone battery life list.

But there's a big caveat there. We got that long-lasting result when we set the Galaxy S21 Ultra's refresh rate to 60Hz. Enabling the dynamic display feature ate up more battery life, with the S21 Ultra lasting 10 hours and 7 minutes on that test. That's still really good.

However, it's not as good as the 10 hours and 40 minutes that the OnePlus 9 Pro lasted with its dynamic display feature turned on. Setting the OnePlus 9 Pro to a 60Hz refresh rate actually lowered the result by 2 minutes to 10 hours and 38 minutes, which is puzzling.

Regardless, the S21 Ultra manages to win the battery life battle, since it clearly can last significantly longer than the OnePlus 9 Pro.

OnePlus 9 Pro with plugged in charging cable

OnePlus 9 Pro (Image credit: Tom's Guide)

If the OnePlus 9 has a slight advantage in terms of battery life, it's got a big edge over the Galaxy S21 Ultra when it comes to recharging the battery. OnePlus equipped this phone with WarpCharge 65T technology which essentially powered up the OnePlus 9 Pro after just 30 minutes. (It got the phone's to 98%, if you want to split hairs.) The OnePlus 9 Pro also supports 30W wireless charging with the right charging accessory.

That wireless speed is faster than the 25W charging speed that the Galaxy S21 Ultra offers. After 30 minutes of charging, our S21 Ultra battery was at 56%, well behind the OnePlus 9 Pro. And we had to supply our own charger — the Galaxy S21 Ultra doesn't ship with one.

Winner: OnePlus 9 Pro

OnePlus 9 Pro vs. Samsung Galaxy S21 Ultra software and special features

Personally speaking, I prefer the Oxygen OS build of Android that OnePlus uses in its phones over Samsung's One UI skin. OnePlus' approach looks cleaner and feels more like a pure Android experience. I've also never warmed up to the rounded, large icons that Samsung favors on its phones.

Galaxy S21 Ultra being used with an S Pen stylus

Samsung Galaxy S21 Ultra (Image credit: Samsung)

Despite all that, Samsung has an edge over OnePlus that has nothing to do with the software. For starters, the Galaxy S21 Ultra is the first phone outside of Samsung's Galaxy Note series to support the S Pen stylus. (You buy the stylus separately for $40 and you'll need a case to store it in, as there's no place on the phone itself to store your new S Pen.) 

Then there's the not inconsiderable matter of Android support. Samsung says it will support three major Android updates along with four years of security updates. That's a year longer than what OnePlus promises for both software updates and security.

Winner: Samsung Galaxy S21 Ultra

OnePlus 9 Pro vs. Samsung Galaxy S21 Ultra verdict

By the thinnest of margins, the Galaxy S21 Ultra noses its way past the OnePlus 9 Pro as the best Android phone you can buy. Despite the OnePlus 9 Pro coming closer to Samsung's crown than ever, the S21 Ultra still wins out, notably in the camera and software support department. 

OnePlus 9 ProSamsung Galaxy S21 Ultra
Price and availability (10 points)86
Design (10 points)87
Display (15 points)1415
Cameras (20 points)1517
Performance and 5G (20 points)1516
Battery life and charging (15 points)1413
Software and special features (10 points)79
Overall (100 points)8183

The Galaxy S21 Ultra's narrow win shouldn't obscure the fact that the OnePlus 9 Pro remains a great phone. And for many people, the S21 Ultra will be the better choice in any OnePlus 9 Pro vs. Samsung Galaxy S21 decision. Besides the slightly better cameras, the S21 Ultra offers a brighter, bigger display, and it's easier to connect to 5G networks on Samsung's phone. The added year of Android support is also ideal if you want to hold onto your phone longer.

But powerful performance with its Snapdragon 888 processor and copious amounts of RAM — not to mention impressive battery life and ultra fast charging — make the OnePlus 9 Pro a very compelling phone. The fact that the cameras are now in the same conversation as some of the best camera phones out there make a case for OnePlus. But Samsung is still king for the best Android phone, even if its crown is strongly contested. 

We can't wait to see how this kind of competition will shape up for 2022. Unfortunately neither phone maker looks to be launching another big phone this year. Samsung has all but confirmed the Galaxy Note 21 isn't happening, plus it's rumored that the OnePlus 9T isn't happening either. So if you want to buy the best Android phone of 2021, it looks like these are going to be the only two contenders. Unless the Google Pixel 6 surprises everyone.

Philip Michaels
Philip Michaels is a senior editor at Tom's Guide. He has strong opinions about Apple, the Oakland Athletics and old movies. Follow him at @PhilipMichaels.