More sustainable than new

Galaxy S21 Ultra 5G 128GB - Black - Unlocked

1 / 5.
Buy now, pay later.

Free delivery
Works with all carriers

Comes with

Charging cable
Get this for even less
Assessment takes 2 minutes and you’ll get an offer instantly. If the price is right, settle up your cart to make it official.
Like starting from . We’ll buy back your old tech for cash.


Galaxy S21 Ultra 5G - Unlocked's customer reviews


256 verified reviews in the last 6 months.

  • M

    Michael E.

    Purchased on February 2, 2024

    The Samsung S21 Ultra appears to be fine in the two weeks since we received it and was as promised. Ordering was easy and delivery was as expected. Our trade-in offer was much lower than we had anticipated ($25.00) for a phone in complete working order without problems. I have previously purchased certified, refurbished smartphones directly from Samsung and felt we received a much better & fairer trade-in offer. While the price of the S21 Ultra was cheaper from Back Market, I believe that I might have fared better buying from Samsung in terms of overall cost. I will research more closely when it's time for our next purchase.
    Galaxy S21 Ultra 5G 128GB - Black - Unlocked

    Reviewed in the United States on February 18, 2024

  • G

    Gerald P.

    Purchased on March 10, 2024

    Trading in my beat-up S21Ultra with damaged screen for this excellent condition replacement enabled me to, in turn, take advantage of trade-in promotion at Samsung Store. My old phone was worthless for trade-in otherwise. The refurbisher who purchased my trade-in tried to claim that it didn't take a charge... but with my photos in hand, the Backmarket staff swiftly dealt with that. Be sure to take photos of live phone, and of each stage of packaging, so that Backmarket is able to support you in case of dispute. Great customer service!
    Galaxy S21 Ultra 5G 128GB - Black - Unlocked

    Reviewed in the United States on March 24, 2024

  • G

    Gene B.

    Purchased on February 29, 2024

    the whole experience was seamless and great! couldn't have asked for a better experience. I purchased S21 Ultra 256gb Unlocked. while I was hesitant about buying a refurbished device, then my device showed up and all the hesitance went right away! will purchase from again !
    Galaxy S21 Ultra 5G 128GB - Black - Unlocked

    Reviewed in the United States on March 18, 2024

  • J

    Jared R.

    Purchased on January 17, 2024

    The phone is great. It works perfectly, the camera is awesome and te phone's processing capabilities are in good condition. I always buy refurbished because it's cheaper and this product came on time and in great condition so, thank you!
    Galaxy S21 Ultra 5G 128GB - Black - Unlocked

    Reviewed in the United States on February 7, 2024

  • E

    Edward E.

    Purchased on December 15, 2023

    Delivery wason time and the phone arrived as described (S21 Ultra in good condition). Everything works fine, except the battery which lasts only half a day under little to moderate useage. From the descriptions of this model, I expected a full day of heavy useage to two days of light use on a fully charged battery. I know it's a used phone, but if the battery is this weak it should have been swapped in order to consider this a refurbished phone.
    Galaxy S21 Ultra 5G 128GB - Black - Unlocked

    Reviewed in the United States on January 1, 2024

  • R

    Rhianna F.

    Purchased on November 10, 2023

    This phone was only 2 years old, and was on here for 600. I couldn't resist that price, and purchased it. It came with 3 small slightly scratched spots on the screen, but that's all. For a refurbished phone, it otherwise works perfect :)
    Galaxy S21 Ultra 5G 128GB - Black - Unlocked

    Reviewed in the United States on November 29, 2023

  • C

    Christopher N.

    Purchased on October 16, 2023

    Greetings. Third time ordering from Back Market. Has not disappointed me yet. I do my research on the phones that strike my interest, see what the new price is and head directly to BM for my price. Four reasons:I work for what I earn so I value my worth; w/o close scrutiny, my device is new and bm refurbished products work/perform/appear as advertised. Last, my carrier connections me without hesitations.
    Galaxy S21 Ultra 5G 128GB - Black - Unlocked

    Reviewed in the United States on November 23, 2023

See all 256 reviews

Reborn vs. brand new

Here’s what you help prevent on average by choosing a reborn smartphone over a brand new one.

171.1 lbs of CO2e

That's like driving an SUV from NYC to Chicago.

6.3 oz of e-waste

That’s around the weight of a baseball.

537.1 lbs of raw materials

That's like 20 dogs digging in your yard for a week.

20,341.2 gallons of water

That's like running a faucet for 3 days

Everything you ever wanted to know about the Galaxy S21 Ultra 5G - Unlocked

Galaxy S21 Ultra 5G 128GB - Phantom black - Unlocked

Our partners are electronics experts who test and verify that each item is 100% functional before it leaves the workshop. This is the reason you benefit from a minimum 1-year warranty with the purchase of a refurbished device at Back Market.

Galaxy S21 Ultra 5G 128GB - Black - Unlocked

  • Manufacturing part numbers (MPN) : SM-G998UZKAXAA
  • Color : Black
  • Screen size (inches) : 6.8
  • Model : Galaxy S21 Ultra 5G
  • Megapixels : 3200 x 1440
  • OS : Android
  • Resolution : 1440x3200
  • Connector : USB-C
  • Carrier compatibility : Unlocked
  • Storage : 128 GB
  • Memory : 12 GB
  • Processor brand : Qualcomm
  • Processor Core : 8
  • Screen type : Dynamic AMOLED 2X
  • Network : 5G
  • Release Date : January 2021
  • Double SIM : No
  • Manufacturer Ref. : SM-G998U1
  • Memory Card Slot : No
  • Verizon compatible : Yes
  • AT&T compatible : Yes
  • T-Mobile compatible : Yes
  • Release Year : 2021
  • eSIM : Yes
  • Foldable : No
  • 5G : Yes
  • SAR head : 0.77
  • SAR body : 1.02
  • Series : Samsung Galaxy S
  • SIM format : Nano
  • SIM card : Single-SIM + eSIM
  • Color (official name) : Phantom Black
  • Product type : Refurbished
  • Brand : Samsung
  • Weight : 8 oz

Welcome to Back Market

The best prices for high-quality reborn tech by sellers we’ve checked and vetted. We don’t mind if you Google us.

Get to know us
  • 1-year warranty
  • Free standard shipping
  • Free 30-day returns
  • Friendly customer service
1 / 3.