Meta title: Quantum Fiber Is Now AT&T Fiber in Seattle WA
Meta description: Quantum Fiber is transitioning to AT&T Fiber in Seattle WA. See what changes, what gets better, and how to switch. Check your address now.
Quantum Fiber Internet Seattle Washington is ending and AT&T Fiber is taking its place across King County.
This is not a rebrand. Lumen Technologies made a strategic decision to exit the consumer internet market. AT&T is moving in with newer infrastructure and a completely different service standard. For Seattle residents who spent years dealing with CenturyLink and Quantum reliability problems that change is significant.
This page explains exactly what is happening, what gets better, and what Seattle households need to do right now.
Check if AT&T Fiber is available at your Seattle address today.
Lumen Technologies built its consumer brand Quantum Fiber on the same infrastructure it inherited from CenturyLink in the Pacific Northwest.
The underlying technology was never the problem. The commitment to maintaining and investing in that infrastructure for King County consumers was. Lumen's long term focus shifted toward enterprise and wholesale markets. Consumer internet in Seattle neighborhoods was not the business they wanted to sustain.
AT&T Fiber is actively expanding through King County as part of a national buildout strategy. Seattle is a priority market. The most tech dense residential city in the Pacific Northwest has a professional population that was underserved by what Quantum Fiber consistently delivered.
Seattle, WAThe customer satisfaction record for CenturyLink and Quantum Fiber in Washington State tells a specific story.
Repeated service interruptions that took longer to resolve than they should. Support response times that did not reflect the urgency of a Seattle engineer sitting offline mid sprint. Infrastructure investment in older King County neighborhoods that lagged behind the pace of Seattle's residential and professional growth. Lumen ranked among the lowest rated internet providers in Washington State over multiple consecutive years in independent customer surveys.
AT&T Fiber brings formal contractual SLA accountability, dedicated fiber architecture, and infrastructure investment designed specifically for the demands of the King County market.
Quantum Fiber serves different Seattle addresses on different infrastructure depending on the age and location of the network serving your specific block.
Some King County streets received genuine fiber to the premises. Others received older hybrid architectures that created performance inconsistencies. AT&T Fiber builds dedicated glass strand infrastructure directly to individual home addresses across Seattle. No hybrid architecture. No legacy copper integration points. Dedicated fiber from the street terminal to your home on every single installation.
Seattle, WAQuantum Fiber was operated by Lumen Technologies. AT&T Fiber is operated by AT&T.
These are two separate companies with different infrastructure, different support systems, and different contractual accountability. Moving from Quantum to AT&T in Seattle means establishing new service with a new provider. A new installation appointment. New equipment. New billing from AT&T directly. Your Quantum account does not transfer automatically.
Quantum Fiber customers in Seattle have Lumen supplied gateway equipment at their address.
AT&T Fiber installation replaces that equipment completely during the technician visit. Your new AT&T gateway supports Wi-Fi 6 and handles both fiber modem and Wi-Fi router functions in one device. You purchase nothing. Everything arrives with the technician. The old Quantum equipment gets removed and the new AT&T gateway gets installed and tested before the technician leaves your King County address.
Support responsiveness was one of the most consistent complaints from Quantum and CenturyLink customers in Seattle.
AT&T provides dedicated commercial support channels for business customers with priority routing and defined escalation procedures. Residential customers receive standard AT&T support which consistently outperforms the Lumen and Quantum experience that King County residents reported over multiple years. When your connection has a problem during a Pacific Northwest winter storm you are not waiting days for a callback.
Seattle, WAAT&T Fiber delivers equal upload and download on every residential plan.
300 Mbps gives 300 Mbps upload. 500 Mbps gives 500 Mbps upload. Gigabit gives 1000 Mbps both ways. Quantum Fiber plans Seattle WA also advertised symmetrical speeds. The real world delivery varied depending on which King County infrastructure served your specific address. AT&T Fiber's dedicated glass strand architecture eliminates that variability entirely. Every Seattle address on AT&T Fiber gets the symmetrical speeds on the plan they ordered.
AT&T Fiber delivers latency under 10 milliseconds throughout the business day.
Not just during quiet Sunday mornings. During Monday standup hours when every Amazon and Microsoft remote worker in your Capitol Hill or Ballard neighborhood goes online simultaneously. Quantum Fiber latency in Seattle varied more significantly during business hours as Lumen's infrastructure carried both residential and enterprise traffic through shared King County network points. For Seattle professionals on daily video calls that consistency difference is audible on every call.
3: No Data Cap on Any AT&T Fiber Residential Plan
AT&T Fiber includes unlimited data on every residential plan in Seattle.
Quantum Fiber also offered unlimited data on most plans. This is one area where the transition does not represent a significant change. What does change is the confidence behind that commitment. AT&T is actively investing in the Seattle market long term. Lumen was actively exiting it.
2: Equipment Changes — What Comes With AT&T Fiber Installation in Seattle
Every Seattle AT&T Fiber installation includes a new gateway at no charge.
Current AT&T models support Wi-Fi 6 which manages many simultaneous connections more efficiently than older Quantum gateway hardware. In a Seattle household running two engineering home offices alongside streaming, gaming, and smart home systems that efficiency shows up as consistent performance under real concurrent load rather than slowdowns during peak household usage hours.
Some AT&T Fiber installations include a separate Optical Network Terminal that mounts on your exterior wall or inside a utility space.
This unit converts the incoming fiber signal before it reaches your gateway. Newer AT&T Seattle installations increasingly use an integrated gateway that skips the separate ONT. Your technician determines which configuration your specific King County address requires on arrival.
The AT&T technician arrives with all equipment included. No purchases required beforehand.
They run fiber from the street terminal to your chosen room. They account for Pacific Northwest property conditions including Seattle's consistent moisture environment. They install the gateway. They test speeds at your ordered tier. They check Wi-Fi coverage throughout your home before signing off. The full visit runs 2 to 4 hours.
No promotional pricing that jumps after 12 months. No equipment rental fees. No data cap overages. Straightforward monthly billing from day one.
Seattle, WA| Plan | Monthly Price | Download | Upload | Data Cap |
|---|---|---|---|---|
| Internet 300 | $55 | 300 Mbps | 300 Mbps | None |
| Internet 500 | $65 | 500 Mbps | 500 Mbps | None |
| Internet 1 Gig | $80 | 1000 Mbps | 1000 Mbps | None |
Existing AT&T mobile customers receive 20 percent off fiber automatically every month.
The gigabit plan drops from $80 to $64 permanently. No promotional window. No expiration. The most affordable gigabit option in Seattle today for anyone already on AT&T mobile service.
AT&T Business Fiber plans for Seattle businesses start at $60 a month for 300 Mbps symmetrical speeds.
Every business plan includes automatic WiFi backup, battery backup, and a formal SLA from day one. For Seattle businesses that experienced Quantum Fiber reliability issues during the Pacific Northwest storm season, those included features represent a fundamental improvement in the foundation their business runs on.
Seattle, WAQuantum Fiber availability Seattle Washington is changing as Lumen transitions out of consumer markets in King County.
Availability and service continuity for existing Quantum customers varies by address and timeline. Check your address with AT&T Fiber today to confirm what is available at your specific Seattle location right now.
Yes. You will need to cancel your Quantum Fiber service as part of the transition.
Confirm your AT&T Fiber installation date before canceling Quantum to avoid a connectivity gap at your Seattle address. Coordinate the cancellation to align with your confirmed AT&T installation date.
Your devices, smart home systems, and wired connections all work normally with AT&T Fiber.
The AT&T gateway supports downstream router connections if you have specific networking equipment you want to keep running. Most Seattle households use the AT&T gateway without additions and find it handles everything without extra configuration.
Most Seattle installations complete in 2 to 4 hours.
The technician handles everything from outdoor fiber routing through Pacific Northwest property conditions to indoor gateway placement, speed testing, and Wi-Fi coverage checks throughout your home before leaving.
For most King County addresses yes and specifically in three areas.
Infrastructure consistency across Seattle neighborhoods. Support accountability when something goes wrong. Business SLA protection for King County commercial customers. Quantum Fiber vs AT&T Fiber Seattle Washington is not a close comparison once those three factors get examined alongside the speed numbers.
The transition from Quantum Fiber to AT&T Fiber in Seattle is underway across King County.
Check your specific address to confirm whether AT&T Fiber is live on your street today and see available plans, pricing, and installation timeline.
See how AT&T Fiber compares to every Seattle provider on our Seattle Competitors page
Working from home in King County? Visit our Work From Home Internet Seattle page for the right speed plan
Ready to book? Read our AT&T Fiber Installation Seattle guide to know exactly what happens on setup day
