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

(19 reviews)

$292.95

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Restored professionally

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

Overall rating

19 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

SM-G988MPN
128 GBStorage
Samsung Galaxy SSerie
0.71SAR head
0.99SAR body
SM-G998UManufacturer Ref.
Phantom BlackColor (official name)
2021Release Year
Dynamic AMOLED 2XScreen type

The Samsung Galaxy S21 Ultra 5G remains a powerful flagship smartphone despite being released in early 2021. It offers a large, vibrant display and a versatile camera system that caters to photography enthusiasts and heavy users alike.

Key features:

Release Date: January 2021
Display: 6.8-inch Dynamic AMOLED 2X, Quad HD+ resolution, 120Hz refresh rate
Processor: Exynos 2100 (Global) / Snapdragon 888 (USA)
Camera: Quad rear cameras including 108MP main sensor, 10MP periscope telephoto with 10x optical zoom
Connectivity: 5G compatible for fast network speeds
Operating System: Ships with Android 11, upgradable to later versions

Who is this for?

The Galaxy S21 Ultra 5G is ideal for users seeking a premium Android experience with a focus on photography and multimedia consumption. It suits professionals, content creators, and tech enthusiasts who want a large, high-resolution display and advanced camera features. Compared to the Galaxy S22 Ultra, it offers similar core capabilities but lacks the built-in S Pen support and some software refinements.

Pros & Cons: Pros Cons High-resolution 108MP camera with versatile zoom options. Large and heavy design may not suit all users. Bright and smooth 120Hz AMOLED display for immersive viewing. Locked to AT&T network, limiting carrier flexibility. 5G connectivity for fast data speeds. No expandable storage option.
Why refurbished?

Choosing a refurbished Samsung Galaxy S21 Ultra 5G supports sustainability by reducing electronic waste while providing a high-quality device. Each pre-owned phone is carefully tested and certified to meet Back Market’s standards for performance and reliability. Learn more about our quality standards.

MPN: SM-G988
Storage: 128 GB
Serie: Samsung Galaxy S
SAR head: 0.71
SAR body: 0.99
Manufacturer Ref.: SM-G998U
Color (official name): Phantom Black
Release Year: 2021
Screen type: Dynamic AMOLED 2X
Model: Galaxy S21 Ultra 5G
Screen size (inches): 6.8
OS: Android
Carrier compatibility: AT&T
Weight: 8 oz
Front camera: 40 megapixels
Brand: Samsung
Color: Black
Network: 5G
Memory (GB): 16 GB
Memory Card Slot: No
SIM card: Physical SIM + eSIM
Resolution: 1440 x 3200
Last OS Compatibility: Yes
Main camera: 108 megapixels
Foldable: 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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