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The best Samsung Galaxy S21 Ultra cases you can buy

You've already splurged on a premium device, now it's time to keep it safe from harm.

Published onMay 15, 2023

Samsung Galaxy S21 Ultra Silver slate
Robert Triggs / Android Authority

While the Galaxy S23 Ultra is now the reigning king, the Samsung Galaxy S21 Ultra is still a powerhouse of a phone. Not to mention an expensive one. You’ll want to protect that investment with a case, but the good news is that you don’t have to sacrifice style or functionality. Whether you’re looking for something slim and sleek or tough and rugged, here at Android Authority we’ve tested and selected the best Samsung Galaxy S21 Ultra cases you can buy, separated into categories.

If you want to learn more about cases, check out our guides to the best phone cases and the best phone accessories you can buy.

Android Authority’s parent company, Authority Media, also owns PHNX.

Best Samsung Galaxy S21 Ultra thin cases

Spigen Thin Fit

Samsung Galaxy S21 Ultra Spigen thin fit case
  • Thin and light
  • Only one color option
  • Very form-fitting
  • Some, but not much, drop protection
  • Matte finish attracts fingerprints
  • Very affordable

If you’re looking for a thin and light Samsung Galaxy S21 Ultra case, this case’s name is self-explanatory. Despite the spartan look and lack of color options, Spigen has been a favorite of ours (and our readers) for years now. This particular case fits extremely snugly around the phone, with precise cutouts that make it look almost like a part of the phone itself. The rubbery finish offers some grip, but it isn’t the best choice if you’re particularly clumsy. The matte finish also looks great, but it is a bit of a fingerprint magnet.

PHNX mnml thin case

PHNX mnml Galaxy S21 Ultra thin case
  • Ultra thin and light
  • Comes in three colors
  • No branding
  • Not much protection
  • A bit pricey

The mnml case for the Galaxy S21 Ultra is just that: minimal. It’s incredibly thin and light at just .35mm, and there’s no branding on the outside of the case. It won’t offer much drop protection, but it does cover the camera bump so it’s far better than nothing. The polypropylene finish also affords some grip to prevent slips. It comes in three finishes: matte black, frosted white, and frosted black.

Ringke Air-S

Samsung Galaxy S21 Ultra Ringke Air S thin case
  • Thin and light
  • Three color options
  • Very affordable
  • Built-in strap or lanyard holes
  • Good, but not perfect, fit

If you want a bit more color, these thin cases from Ringke are a safe bet. There isn’t anything overly fancy about them, but one unique feature we love is the inclusion of strap/lanyard holes on the lower part of the sides. It’s a bit of a throwback feature that many new phone cases skip. Since this kind of silicon case isn’t compatible with adhesive accessories like PopSockets, it’s also a great way to prevent drops, which thin cases like this can only mitigate to a certain degree.

Caseology Nano Pop

Samsung Galaxy S21 Ultra Caseology Nano Pop case
  • Eye-catching design
  • Thin-ish
  • Solid protection
  • More styles available

Want a case that can make your Galaxy S21 Ultra even more stylish? Check out Caseology cases. The Nano Pop pictured above features a two-tone design that’s truly eye-catching, and it does so without adding too much bulk to your phone. If you don’t mind a bit more bulk, the Caseology Parallax switches things up with an attractive textured exterior that comes in a variety of colorways. For a more subdued look, the Caseology Vault comes in matte black and gray, with a sandstone finish that won’t slip or collect fingerprints.

Best Samsung Galaxy S21 Ultra clear cases

Spigen Ultra Hybrid

spigen ultra hybrid
  • Relatively thin and light
  • Precise cutouts
  • Good protection
  • Clear cases tend to yellow over time
  • Difficult to keep clean
  • Not the easiest to remove

The Spigen Ultra Hybrid offers good protection for the Galaxy S21 Ultra with the combination of a polycarbonate back and TPU bumper. You have the choice between a clear option or one with a matte black bumper. The bumper is a little stiff initially, so I had to pull a little harder than I’d have liked to remove the case. The PC back is also a huge fingerprint magnet for my oily fingers, so it’s a difficult case to keep clean. If you’re looking for a thinner, lighter, and simpler TPU case, the Spigen Liquid Crystal is worth considering as well, but won’t be as protective as the Ultra Hybrid.

Ringke Fusion

Ringke Fusion clear case
  • Excellent transparent case
  • The clear version is very cheap
  • Different styles available
  • Built-in strap or lanyard holes
  • Good fit

The Ringke Fusion is quite similar to the Spigen Ultra Hybrid in its design. A PC back and TPU bumper provide ample protection and let you show off the phone’s design. The bumper is softer than the Spigen, so we had an easier time installing and removing the case. The standard clear version, the cheapest of the lot, is a bit of a fingerprint magnet, but you can get the matte clear version to avoid this problem. The Fusion is also available in a few different styles if you’re looking to add some flair. Like Spigen, Ringke has a clear TPU case as well, the Ringke Air, but it was a little too flimsy for our liking.

ESR metal kickstand case

esr metal kickstand case for the galaxy s21 ultra
  • Solid protection
  • Sturdy metal kickstand
  • Bulky because of the kickstand
  • Two styles available

If the name isn’t enough of a giveaway, it’s all about the metal kickstand with this case. It’s a sturdy, well-built stand that lets you prop the phone up in both landscape and portrait. Even though the Galaxy S21 Ultra is a big and heavy phone, we weren’t worried about the phone falling over at any point. ESR suggests not setting the kickstand to an angle beyond 60 degrees to prevent the stand from loosening, though. You’ll rarely find kickstand cases outside of heavier rugged options, but this ESR case is a welcome exception to the rule.

Best Samsung Galaxy S21 Ultra wallet cases

TUCCH wallet

tucch wallet with four card slots and cash pocket
  • Good-looking faux leather
  • Folio cover doubles as a kickstand
  • Four card slots and a cash pocket
  • Plenty of color options
  • RFID blocking

The TUCCH wallet comes with a classic wallet phone case design. The case is made with premium PU leather that looks stylish and feels great. The folio cover doubles as a kickstand and also comes with an additional layer for RFID blocking. The case comes with four card slots and a large pocket for cash, but packing it too much makes it a little thicker than we would like. We didn’t have any problems closing the magnetic clasp even with all the card slots filled, though. There are plenty of color options to choose from as well, but the classic black looks the part of a stylish leather wallet case.

Spigen Slim Armor CS

spigen slim armor cs
  • Non-traditional wallet design
  • The rear card slot can hold up to three cards
  • Solid protection
  • Good fit

The Spigen Slim Armor CS skips the traditional wallet case design for a more modern card holder case style, but you can still carry three cards or some cash. It’s also thin, but protective, with Spigen staples like Air Cushion technology ensuring that it’ll survive a bump or drop. Spigen says that the rear card slot can hold up to three cards. It’s definitely a squeeze with more than two though, especially if the cards are embossed. The “door” of the card slot isn’t easy to open and the mechanism isn’t very smooth, which is a little disappointing.

Vena vCommute

Vena vcommute wallet case
  • Excellent protection
  • Good kickstand
  • Can hold up to three cards
  • Compatible with magnetic car mounts

The Vena vCommute doesn’t look like a wallet case at first glance, but we like this design more than the Slim Armor CS or the Smartish Slayer. It’s a stylish faux leather case with a hidden compartment on the back that can hold up to three cards. The leather flap that hides the compartment can also be folded and locked into a multi-angle kickstand that works really well, despite how heavy and big the S21 Ultra is. It’s also military-grade certified for drop protection, so you won’t have to worry about bumps and drops.

Looking for more? Check out our list of thebest wallet case brands available.

Best Samsung Galaxy S21 Ultra rugged cases

Otterbox Defender

otterbox defender
  • Complete all-around protection
  • Thick and bulky
  • Comes with a belt clip holster
  • Port covers keep out dust and debris

Otterbox is the go-to case brand for rugged cases, and the Defender is one of the best options from the case maker. We’re not a fan of how thick and bulky the case is, but there’s no denying that it’s made to take a beating. The case also comes with a belt clip holster that doubles as a kickstand. It’s not the best kickstand implementation we’ve seen and the plastic isn’t very sturdy, but it works. There are a few color options available with the Defender as well.

UAG Monarch

uag monarch
  • Very protective but feather-light
  • Stylish design
  • Expensive
  • Difficult to remove

The Monarch is one of the best cases you can get from UAG and cranks the protection up to 11. At first glance, the Monarch looks the part of an ultra-rugged case, with its five layers of material, reinforced corners, grip-y sides, and a raised back. But we were impressed by how light the case is despite what its looks would suggest. Even though it’s quite thick, you can still use NFC payments or wirelessly charge the phone without taking the case off. Different options add a splash of color to the phone as well.

Spigen Tough Armor

spigen tough armor
  • Good protection without the thickness
  • Mil-grade certified
  • Allows wireless charging
  • Flimsy kickstand

The Tough Armor is one of the most durable cases Spigen makes, and it offers plenty of hybrid protection. You’ll find a layer of soft TPU that’s great against drops and a tough polycarbonate shell to keep scratches at bay. It even packs a built-in kickstand to prop the phone up in landscape orientation. Unfortunately, the kickstand is the only blemish on an otherwise great case. It’s thin, plastic, and flimsy. We didn’t have any problems propping the phone up, but durability is definitely a concern with a phone as heavy as the S21 Ultra.

Looking for more? Check out our list of the best rugged case brands available.

Best Samsung Galaxy S21 Ultra leather cases

Otterbox Strada

otterbox strada genuine leather case
  • Stylish leather folio
  • Two car slots
  • Military-grade drop protection
  • Expensive

The Otterbox Strada comes with all the protection of an Otterbox case in a stylish leather folio case. The genuine leather case looks and feels great. A magnetic metal latch holds the folio cover in place and it’s a solid magnet. It comes with two card slots, so if you’re looking for more, the wallet cases above are the better option. But if you want a stylish leather case for the S21 Ultra, the Strada is an excellent case.

FYY leather wallet

fyy leather wallet with three card slots and a cash pocket
  • Genuine leather
  • Has three card slots and a cash pocket
  • Strong magnetic closure

If you’re looking to completely ditch your wallet with a stylish leather case, the FYY case is the one for you. The genuine leather wallet looks fantastic and comes with three card slots and a large pocket for cash. The case comes with an additional RFID blocking layer to keep your cards safe as well. The TPU case inside does a good job of holding the phone in place but is a little too thin, so it might not do a great job of protecting the phone if it falls with the folio cover open. Luckily, the magnetic closure is very sturdy.

Samsung leather case

samsung leather case
  • Thin and light
  • Soft leather gives a premium feel.
  • Not very protective.
  • Expensive

We’re back to the simple designs, but this first-party leather option from Samsung adds a premium feel to your Galaxy S21 Ultra. It comes in black and brown, and each version features aluminum accents that help to complement the leather finish. The interior of this leather case is lined with soft microfiber, so your new phone should stay in top shape for years to come. However, there’s not much of a front lip to protect your 6.8-inch display, so you might want a screen protector.

Best Samsung Galaxy S21 Ultra S Pen cases

Samsung S-View cover with S-Pen slot

samsung s view cover with s pen slot
  • Control the phone without opening the folio cover
  • Built-in S-Pen slot
  • Expensive

Samsung’s official cases for its flagships are really expensive. But if you’re going to splurge, the S-View cover is the case to get. A quick glance to check the time, or swiping on the cover to answer calls, see notifications, and control my music without opening the cover was a lot of fun. The regular version of the S-View cover is the one to get if you’re looking for different color options. But if you have an S-Pen, the version with the built-in slot is the better way to go. If you don’t want to S-View cover, Samsung also has a standard silicone cover with an S-Pen slot available.

Spigen Liquid Air P

spigen liquid air p galaxy s21 ultra case with s pen slot
  • Thin and light
  • The textured back adds grip
  • S-Pen slot
  • Form-fitting

The Spigen Liquid Air P is essentially the thin and light Liquid Air with the added benefit of an S-Pen slot. Despite how thin and form-fitting it is, the case is military-grade certified and comes with Air Cushion technology for extra corner protection. The only issue with the S-Pen slot is that there is a very specific way to put it in the slot (the Samsung logo should face the front or back). You can squeeze it in the wrong way, but then it becomes very difficult to remove the stylus.

Supcase UB Pro with S-Pen slot

supcase ub pro with s pen slot
  • Excellent protection
  • Good kickstand
  • Built-in S-Pen slot
  • Different color options

This version of the UB Pro by Supcase is nearly identical to the standard version but with an extra S-Pen slot. It comes with all the benefits of the regular case, including a multi-piece hybrid design with a thick TPU bumper around the edges. There’s also a rotating belt holster and a built-in kickstand that is plenty sturdy. Unlike a lot of rugged cases, there are a few color options available if the standard black isn’t for you. The UB Pro for the S21 Ultra doesn’t come with a screen protector panel, but I actually prefer that given the issues they can cause with the fingerprint scanner.

Best Samsung Galaxy S21 Ultra custom cases


skinit custom cases
  • Completely customizable cases
  • Great selection of branded cases
  • Good dual-layer protection

Skinit is a well-known phone skin brand, but if you’re looking for more protection, the company has plenty of custom and customizable cases available as well. The Impact case is a dual-layer hybrid case with enhanced corner protection and a raised lip around the screen. Of course, the big selling point here is customization. You can add your own images to the case, or choose from hundreds of custom designs featuring sports teams, universities, superheroes, TV shows, movies, and a lot more.

Case24 custom cases

case24 custom cases for the samsung galaxy s21 ultra
  • Different case types
  • Customizable printed cases
  • Solid protection with the heavy-duty case
  • Good fit

Unlike Skinit, Case24 leaves the customization entirely up to you. You can add your own pictures to make the case truly your own. What’s unique about Case24 is that a variety of case types are available. You can choose from a standard thin-fit TPU case, a dual-layer hybrid case where the custom design goes around the edges, and a fully-printed wallet case.

Best Samsung Galaxy S21 Ultra specialty cases

Moment Thin case

moment case compatible with moment lenses
  • Compatible with Moment lenses
  • M-force compatible
  • Ultra-thin and light
  • Not the most protective

Moment’s Thin cases are meant for one thing and that is to let you use Moment’s lenses easily with your phone. The camera section is designed to hold the lens in place properly and stop it from rotating. The new cases are also now compatible with Moment’s M-Force magnetic mounts, which work just like MagSafe accessories. It’s not the most protective case, though, with only six feet of drop protection.

How we test phone cases

We rigorously test smartphones, accessories, and other products in our reviews here at Android Authority, and there are plenty of factors we consider before recommending a phone case. This is particularly important with the large, heavy, and generally unwieldy Galaxy S21 Ultra.

  • Protection: Different cases offer different levels of protection. While an ultra-thin case is great to keep the phone scratch-free, it won’t do much in case of a drop. We simulate real-world drops to test durability for hybrid and rugged cases, like if the phone falls while pulling it out of the pocket. We also look at corner protection, the lip around the display and rear camera, and whether you get covered buttons.
  • Build materials and quality: Poor-quality polycarbonate cases are prone to cracking when installing or removing them. The fit also matters. If you have to apply a lot of pressure to remove a case, the case will crack. With softer TPU cases, continuously removing the case might cause it to loosen around the corners, affecting the fit and protection you will get.
  • Grip: You don’t want a case that will slip out of your hand or slide off a table. Apart from hands-on testing, we slide the phone across different surfaces like wood and marble to see how slippery (or not) it might be. Cases get extra points if they have ridges or bumps along the sides or back to help add to the grip.
  • Installation and removal: Installing a case shouldn’t be difficult, and we don’t consider it if a case can’t even be installed easily. However, removing a case can be a pain with even high-quality cases and potentially damage your phone. It’s a big no-no if you have to apply a lot of force to the point where you feel the phone almost bending.
  • Design and colorways: Design and color are personal choices, but it’s nice to have options. We also have a dedicated category for clear cases to show off the phone’s design.
  • Price: You don’t have to spend too much to get a good case. You can always find $15 cases that offer as much protection, if not more, than $75 options.

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