Motorola SURFboard SB6121 Cable Modem (SB6121)

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The Motorola SURFboard SB6121 Cable Modem (SB6121) was $10 when we checked it on 2026-10-12. That is about 90 percent below the median of the 14 prices we have recorded for it.

A new and improved version of the world's most widely deployed DOCSIS cable modems. For the residential cable subscriber who wants a powerful modem capable of delivering a high-speed data service at blazing fast speeds.10 / 100 / 1000 Base-T Ethernet Port (RJ-45) and 1-Year Limited Warranty. Additional information:• Requires CABLE Internet Service, if not sure your provider is CABLE call them to confirm • Compatible with ALL Major CABLE providers like Comcast, Cox, Charter, Time Warner, Mediacom, Bright House

Editor's note

Worth checking your provider before buying, since it is not compatible with FiOS, U-verse, or Comcast Xfinity anymore. For a supported cable plan it is a proven workhorse.

Motorola SURFboard SB6121 Cable Modem (SB6121) price history

14 weekly checks of our own, from 2026-06-25 to 2026-10-12. How our price tracking works

$104.99$9.85

Typical

Jun 25Jul 22Aug 18Sep 14Oct 12

Lowest

$9.85

Aug 31, 2026

Typical

$99.99

median of 14 weekly checks

Highest

$104.99

Jun 25, 2026

Latest

$10.00

checked Oct 12, 2026

Typical price is the median of the 14 weekly checks we have taken, not the manufacturer list price. Every discount figure on this site is measured against it.

Every observation (14)

Date	Price	Source
Jun 25, 2026	$104.99	Weekly check
Jun 29, 2026	$104.99	Weekly check
Jul 6, 2026	$104.99	Weekly check
Jul 13, 2026	$101.99	Weekly check
Jul 20, 2026	$99.99	Weekly check
Jul 27, 2026	$99.99	Weekly check
Aug 3, 2026	$99.99	Weekly check
Aug 31, 2026	$9.85	Weekly check
Sep 7, 2026	$32.80	Weekly check
Sep 14, 2026	$32.80	Weekly check
Sep 21, 2026	$19.13	Weekly check
Oct 1, 2026	$10.00	Weekly check
Oct 5, 2026	$10.00	Weekly check
Oct 12, 2026	$10.00	Weekly check

About this item

Compatible with Time Warner Cable, Charter, Cox, Cablevision, and more
Not compatible with Verizon FiOS or AT&T U-verse, no longer approved by Comcast Xfinity
Requires Cable Iternet Service, if not sure your provider is CABLE call them to confirm
BROWN BOX models NOT VALID for this item when sold as New, should report to Amazon immediately and RETURN to Seller
Wired modem only, does NOT include WIFI Router or VOIP Telephone adapter. Gigabit Ethernet port to connect to computer or Router for fast downloads.
Internet speeds based on your Cable providers service - up to 172 Mbps download and 131 Mbps upload. 4 Download and 4 Upload Channels.

Details

Brand: ARRIS
Item Weight: 1.5 pounds
Model Number: SB6121
Connectivity Technology: Wired
Compatible Devices: Personal Computer, Router, Laptop
Item Dimensions L x W x H: 6.4"L x 2"W x 8.7"H
Color: Black

#pc-hardware

Motorola SURFboard SB6121 Cable Modem (SB6121): common questions

Is the Motorola SURFboard SB6121 Cable Modem (SB6121) worth it?

Worth checking your provider before buying, since it is not compatible with FiOS, U-verse, or Comcast Xfinity anymore. For a supported cable plan it is a proven workhorse. Its Amazon listing shows 4.4 out of 5 stars across 11,627 ratings, which is the retailer's figure and not our verdict.

How much does the Motorola SURFboard SB6121 Cable Modem (SB6121) cost?

The Motorola SURFboard SB6121 Cable Modem (SB6121) was $10 when we checked it on 2026-10-12. The median of the 14 prices we have recorded for it is $99.99. Prices change often, so the live retailer link carries the current number.

Is now a good time to buy the Motorola SURFboard SB6121 Cable Modem (SB6121)?

At $10 the Motorola SURFboard SB6121 Cable Modem (SB6121) is about 90 percent below the median of the 14 prices we have recorded for it, though we have seen it as low as $9.85 on 2026-08-31.

What is the lowest price the Motorola SURFboard SB6121 Cable Modem (SB6121) has been?

The lowest price on our record for the Motorola SURFboard SB6121 Cable Modem (SB6121) is $9.85 on 2026-08-31, and the highest is $104.99 on 2026-06-25. That record is 14 weekly checks we took ourselves.