Galaxy S21 Ultra 5G • Locked AT&TSilver • 128 GB • Physical SIM + eSIM

(37 reviews)

$295.16

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Customer reviews for Galaxy S21 Ultra 5G • Locked AT&T

Overall rating

37 verified reviews

Rating details

Battery
4.5/5
Shipping
4.5/5
Lens & Camera
4.7/5
Accessories
4.3/5
Packaging
4.5/5
Overall performance
4.1/5
Appearance
4.4/5

Reviews

Paul S.
Verified purchase
Reviewed 11/16/25, United States.
The device arrived in a timely manner in a condition and functionality stated in buy Back Market This is my second order using this site I also purchased an s22 ultra and have been very satisfied with both purchases
Galaxy S21 Ultra 5G 128GB - Black - Locked AT&T
Galaxy S21 Ultra 5G 128GB - Black - Locked AT&T
Condition
Good
Light signs of wear. The body may have light micro-scratches. For items with screens, the screen will have no scratches.
Purchased
11/2/25
Debbie L.
Verified purchase
Reviewed 11/10/24, United States.
Phone is perfect for me! So glad I could buy an ATT refurb, since some features are not available on unlocked devices. Replaced the same phone I had, an unlocked S21 Ultra with a cracked screen which would cost more to fix than this refurb, and since ATT service/reception has been going steadily downhill, really appreciate that I can use WiFi calling now. Yeah, I should switch but no guarantee that service would be any better. Totally happy with this purchase!
Galaxy S21 Ultra 5G 128GB - Black - Locked AT&T
Galaxy S21 Ultra 5G 128GB - Black - Locked AT&T
Condition
Excellent
Almost no signs of wear. The body may have very light micro-scratches. For items with screens, the screen will have no scratches.
Purchased
10/31/24
Renee L.
Verified purchase
Reviewed 8/14/23, United States.
I was honestly worried getting a used phone. But I wasn't paying 1000 for a phone. so I went back and worth for couple weeks and I had message company and asked few questions. They was awesome and answered all my questions. so I ordered the phone I wanted and it was here in 3 days. let me tell you. This phone looks brand new. I have had it for couple days and no problems at all. I absolutely love it. I will be buying more stuff from here.
Galaxy S21 Ultra 5G 256GB - Dark Gray - Locked AT&T
Galaxy S21 Ultra 5G 256GB - Dark Gray - Locked AT&T
Condition
Excellent
Almost no signs of wear. The body may have very light micro-scratches. For items with screens, the screen will have no scratches.
Purchased
8/8/23
Mason H.
Verified purchase
Reviewed 10/17/24, United States.
The condition was near perfect though it had minor screen burn in only noticeable if you really look into it
Galaxy S21 Ultra 5G 128GB - Black - Locked AT&T
Galaxy S21 Ultra 5G 128GB - Black - Locked AT&T
Condition
Fair
Signs of wear. The body may have a few visible scratches and dents. Items with screens may have light scratches.
Purchased
10/15/24
Eric H.
Verified purchase
Reviewed 3/5/24, United States.
This is my 3rd purchase from backmartket and I must say, they have never failed to deliver a quality product to me! This phone is in amazing condition it has 1 tiny little scuff on the screen that was maybe ⅛ of an inch long that was super shallow and completely disappeared when I put a screen protector on it!everything else works perfectly and it is a major improvement from my s10 thank your again backmartket I've recommended you to everyone that's said they needed a new phone and plan on purchasing all my tech from you in the foreseeable future if possible
Galaxy S21 Ultra 5G 128GB - Black - Locked AT&T
Galaxy S21 Ultra 5G 128GB - Black - Locked AT&T
Condition
Excellent
Almost no signs of wear. The body may have very light micro-scratches. For items with screens, the screen will have no scratches.
Purchased
2/18/24
Misty L.
Verified purchase
Reviewed 3/26/25, United States.
I got my device and the touch screen was either unresponsive or intermediate... so I got the label, the box and proofed of purchase... I sent it out 16th and got back to the seller on March 20th. so 2 business days would be the 21st, 24th, 25th, and 26th... with messaging back market waking what's going on the I get message back with that I believe is AI they are looking into it and never given me a direct answer just asking me to be patient... I'm losing wages with this problem as that's my works phone....
Galaxy S21 Ultra 5G 128GB - Black - Locked AT&T
Galaxy S21 Ultra 5G 128GB - Black - Locked AT&T
Condition
Fair
Signs of wear. The body may have a few visible scratches and dents. Items with screens may have light scratches.
Purchased
2/26/25
Jake M.
Verified purchase
Reviewed 10/31/24, United States.
I ordered an "excellent" condition phone for a little extra. The phone i got has scratches and dings on the metal body around the edges. Nothing to impair the use of the device, but one can't help feeling a bit ripped off. When you pay extra for condition, you expect to get what you pay for. Lesson learned on this one...
Galaxy S21 Ultra 5G 128GB - Silver - Locked AT&T
Galaxy S21 Ultra 5G 128GB - Silver - Locked AT&T
Condition
Excellent
Almost no signs of wear. The body may have very light micro-scratches. For items with screens, the screen will have no scratches.
Purchased
10/26/24

Everything you ever wanted to know about the Galaxy S21 Ultra 5G • Locked AT&T

Durability
Overall performance
Camera
Screen quality

6.8Screen size (inches)
AndroidOS
1.02SAR body
Physical SIM + eSIMSIM card
Phantom SilverColor (official name)
8 ozWeight
NoFoldable
40 megapixelsFront camera
SilverColor

The Samsung Galaxy S21 Ultra 5G remains a strong contender in the premium smartphone segment despite being released in early 2021. Known for its large display and versatile camera system, it continues to meet the needs of users who want a high-end Android device with advanced features.

Key features:

Release Date: January 2021
Display: 6.8-inch Dynamic AMOLED 2X, QHD+ resolution, 120Hz refresh rate
Processor: Exynos 2100 (global) / Snapdragon 888 (USA)
Camera: Quad rear cameras including 108MP wide, 12MP periscope telephoto, 10MP telephoto, and 12MP ultra-wide
Connectivity: 5G compatible ensuring fast network speeds and low latency
Operating System: Ships with Android 11, upgradeable to later versions

Who is this for?

The Galaxy S21 Ultra 5G is suited for power users, photographers, and multimedia consumers who want a large, vibrant display and a versatile camera setup. It’s also ideal for professionals who require strong performance and connectivity. Compared to newer Galaxy models, it offers many flagship features but may lack some latest software updates and enhancements.

Pros & Cons: Pros Cons Large, vibrant AMOLED display with smooth 120Hz refresh rate. Heavier and bulkier than some newer flagship models. Versatile quad-camera system with high-resolution sensor and telephoto zoom. May not receive the latest Android updates as promptly as newer devices. Strong performance powered by Snapdragon 888 / Exynos 2100. Locked to AT&T, limiting carrier flexibility.
Why refurbished?

Choosing a refurbished Samsung Galaxy S21 Ultra 5G supports sustainable consumption by extending the device's lifecycle. Back Market ensures each pre-owned device undergoes thorough testing and quality checks to meet high standards. Learn more about our quality standards.

Screen size (inches): 6.8
OS: Android
SAR body: 1.02
SIM card: Physical SIM + eSIM
Color (official name): Phantom Silver
Weight: 8 oz
Foldable: No
Front camera: 40 megapixels
Color: Silver
Connector: USB-C
Brand: Samsung
Serie: Samsung Galaxy S
Storage: 128 GB
Last OS Compatibility: Yes
Manufacturer Ref.: SM-G998U
Release Year: 2021
Memory (GB): 12 GB
Carrier compatibility: AT&T
Resolution: 1440 x 3200
SAR head: 0.77
Main camera: 108 megapixels
Model: Galaxy S21 Ultra 5G
Network: 5G
Screen type: Dynamic AMOLED 2X
Memory Card Slot: No

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Customer reviews for Galaxy S21 Ultra 5G • Locked AT&T

Overall rating

Rating details

Reviews

Reviews

Paul S.

Debbie L.

Renee L.

Mason H.

Eric H.

Misty L.

Jake M.

Popular searches

Everything you ever wanted to know about the Galaxy S21 Ultra 5G • Locked AT&T

Durability

Overall performance

Camera

Screen quality

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