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Zayo
North America's largest independent fiber network, selling everything from dark fiber and 400G wavelengths to dedicated internet. We quote it for high-capacity routes, diverse paths and data centers, and for office internet where Zayo is already in the building.
The short answer
Zayo is an independent fiber infrastructure company with about 224,000 route miles in North America after it bought Crown Castle's fiber business in May 2026. It sells at every layer: dark fiber, wavelengths on a 400G-enabled network, Ethernet, and dedicated internet from 100 Mbps to 100 Gbps on its Tier 1 IP backbone. On a 36-month term, Zayo DIA typically runs $475 to $575 a month at 100 Mbps and $800 to $975 at 1 Gbps, with installs around three months. It gets more competitive as bandwidth rises, and it is at its best where you need fiber, not just internet.
Speeds
DIA 100 Mbps to 100 Gbps; wavelengths to 400G; dark fiber
1 Gbps monthly
$800 to $975 on a 36-month term
Install interval
About three months typical for DIA
SLA
DIA 99.9% unprotected, 99.95% protected (Zayo service description)
Carrier overview
What Zayo offers
Zayo builds and owns fiber, then sells it at whatever layer the customer wants:
Dark fiber. Leased strands for exclusive long-term use, metro and long-haul. Zayo lists 32,000 on-net buildings and 1,700 on-net data centers for dark fiber, and says its long-haul dark fiber is about 90% underground. You light it with your own optical equipment.
Wavelengths. Point-to-point optical transport on a 400G-enabled North American network, with protected and diverse options and more than ten unique long-haul routes. Zayo's Waves on Demand program pre-provisions 100G waves on selected routes so they can be activated through its portal in hours rather than weeks.
Private networks and Ethernet for connecting sites, and CloudLink for private connections to cloud providers.
Dedicated Internet Access and IP Transit. 100 Mbps to 100 Gbps on Zayo's Tier 1 backbone, IPv4 and IPv6 dual stack, static, default or BGP routing. Zayo says it augments backbone capacity when links reach 50% utilization. DDoS protection is a paid overlay.
DynamicLink (Zayo's network-as-a-service product), plus managed SD-WAN, SASE and Starlink-based services.
In May 2026 Zayo closed its purchase of Crown Castle's fiber business, adding about 90,000 route miles and 40,000 on-net enterprise locations in US metro markets. Crown Castle's small cells went to a separate company, Arium Networks. Zayo's European business has operated as a separate entity, Zayo Europe, under the same ownership since 2024.
Where they are strongest
Zayo is on the shortlist whenever the requirement is fiber itself: dark fiber between two data centers, a 100G or 400G wave between metros, or a route that has to be physically diverse from another carrier. Its long-haul routes include paths built specifically to fill gaps other carriers leave, which is what makes it useful as the second leg in a diverse design. Vertical Systems Group ranked Zayo second in US wavelength services for 2025, behind Lumen.
The Crown Castle fiber purchase matters for buyers in large US metros. Many office buildings and data centers that were Crown Castle on-net are now Zayo on-net, which can change who the lowest-cost lit carrier is in a building.
How we quote them
We quote Zayo for 10 Gbps and higher dedicated internet, wavelengths, dark fiber, diverse-path designs and DynamicLink. For a standard 1 Gbps office circuit, Zayo is competitive mainly in buildings it already serves.
Before a Zayo quote goes next to anyone else's, we confirm three things:
Which Zayo network the building is on. After the Crown Castle purchase, some buildings are on legacy Crown Castle fiber now owned by Zayo. We confirm on-net status and the route to the nearest Zayo hub.
Protected or unprotected. Zayo's published availability objectives differ by protection, for both DIA and waves. A cheap unprotected circuit is a different product from a protected one.
Dark fiber or lit. If you are pricing dark fiber, we price the equivalent wavelength too, because the cheaper monthly number is not always the cheaper total. See Zayo dark fiber vs lit wavelengths.
Services we quote
Dark fiber · Wavelengths · Private networks · Dedicated Internet Access · IP Transit · Ethernet · WANs · CloudLink · DynamicLink NaaS · Managed SD-WAN, SASE and Starlink · DDoS protection
Coverage
Metro fiber in 400+ markets across the U.S., Canada and Europe
Carrier type
National
Carrier-neutral: we work for you, our client, with no carrier or service provider bias.
Product comparison
Zayo dark fiber vs Zayo wavelengths
Dark fiber | Wavelengths | |
|---|---|---|
What you get | Unlit strands, for your exclusive use | A lit optical channel at a fixed speed |
Who lights it | You, with your own optical gear | Zayo |
Capacity | Whatever your equipment supports | The contracted speed, up to 400G |
Who monitors and repairs the optical layer | You (Zayo repairs the fiber) | Zayo |
Published availability objective | Zayo cites 99.999% uptime on its network | 99.999% protected, 99.9% unprotected (Zayo GSA schedule) |
Best for | Large, growing, long-term point-to-point needs | Fixed high-capacity links without an optical team |
Dark fiber is cheapest per gigabit only if you have the engineers and the time horizon to use it. Our full walkthrough is in Zayo dark fiber vs lit wavelengths.
Alternatives
When another carrier fits better
A standard office circuit where Zayo is not lit. A carrier already in the building, such as Verizon Business, AT&T Business or Comcast Business, will usually install faster and cost less.
You want the shortest install for a wave on a common route. Lumen publishes a 20-business-day delivery commitment on its RapidRoutes. Price both. See Lumen vs Zayo for wavelengths.
Low-cost internet in a lit tower or data center. Cogent is usually cheaper on-net, especially as a second path.
Managed security and voice on the same contract. Lumen bundles more managed services than Zayo does, and Uniti sells them through Uniti Solutions alongside Uniti Fiber.
The Southeast and secondary markets. Uniti's network is often denser across the Gulf Coast and the former Windstream footprint.
Typical pricing
What dedicated internet usually costs here
Slightly above the market average at 100 Mbps and slightly below at 1 Gbps; Zayo's pricing gets more competitive as bandwidth climbs. Typical dedicated install is about three months.
| Tier | Typical monthly | Market average |
|---|---|---|
| 100 Mbps | $475 – $575 | ≈ $500 |
| 1 Gbps | $800 – $975 | ≈ $900 |
Contract notes
What Zayo's published service terms say
Zayo does not publish a single current SLA document. These are the published terms we could find, and how we use them:
DIA availability objectives. Zayo's DIA and IP Transit service description (version 1.1, revised November 2021) sets 99.9% availability for unprotected circuits and 99.95% for protected circuits. Zayo's current DIA page says "99.9% uptime." Ask for the SLA attachment that applies to your order, because the service description predates several network upgrades.
DIA repair targets. The same document sets a mean time to repair of 4 hours for equipment or jumper failures and 12 hours for fiber cuts on unprotected circuits.
Wavelength objectives. Zayo's federal GSA schedule (pricing effective August 2025) lists 99.999% availability for protected waves and 99.9% for unprotected waves, and defines three wave types: Basic (unprotected, shared infrastructure), Custom (protected or diverse, with a defined path or latency profile) and Dedicated (dedicated optical infrastructure and equipment).
Dark fiber is a lease, not ownership. On the same schedule, Zayo leases dark fiber strands; the customer is responsible for everything on the premises side of the demarcation point and does not get the right to access, splice or modify the fiber itself. If you want an IRU (a long-term right of use) rather than a lease, say so at the start.
Credits. We did not find a published Zayo credit schedule. We get it in writing for every Zayo quote before it goes next to a carrier that does publish one.
Term, renewal and early termination live in your service order and master agreement. See Read this before you auto-renew a 36-month term.
Learn the lingo
Frequently asked questions
What does Zayo do?
Zayo builds and owns fiber networks and sells capacity on them: dark fiber, wavelengths, Ethernet, private networks, dedicated internet and IP transit. Its customers range from carriers, hyperscalers and banks to enterprises and public sector. It is not a residential provider.
Is Zayo a Tier 1 internet provider?
Zayo describes its IP network as Tier 1, and CAIDA ranks it among the top ten global internet providers by its AS rank. In practice, that means Zayo DIA reaches most of the internet through its own peering relationships rather than buying transit.
How much does Zayo dedicated internet cost?
On a 36-month term, Zayo DIA typically runs $475 to $575 a month at 100 Mbps and $800 to $975 at 1 Gbps, and it gets more competitive at 10 Gbps and above. Zayo does not publish DIA pricing; the address, term and on-net status set it.
How long does a Zayo install take?
About three months is typical for DIA. On-net buildings can be faster, and builds take longer. For 100G waves on routes in Zayo's Waves on Demand program, activation can take hours because the capacity is pre-provisioned.
What did Zayo buy from Crown Castle?
In May 2026 Zayo closed its purchase of Crown Castle's fiber business, adding about 90,000 route miles and 40,000 on-net enterprise locations in US markets. Crown Castle's small cell business went separately to Arium Networks. If you had Crown Castle fiber service, Zayo is now your carrier.
Should I buy Zayo dark fiber or wavelengths?
Buy wavelengths if you need a fixed high-capacity link and do not run your own optical network. Consider dark fiber if you need very high, growing capacity on a point-to-point route, plan to keep it for many years, and have the engineers to light and monitor it. We price both on the same route before you decide.
What SLA does Zayo offer?
Zayo's published DIA service description sets 99.9% availability for unprotected and 99.95% for protected circuits, with a 4-hour repair target for equipment and 12 hours for fiber cuts. Its federal schedule lists 99.999% for protected waves. We confirm the credit schedule in writing for each order, because Zayo does not publish one.
Does Zayo serve Europe?
Zayo's European business has operated as Zayo Europe, a separate company under the same ownership, since 2024. The two provide services to each other's customers under formal agreements. For a transatlantic design, we confirm which entity contracts each end.
Sources
Zayo dark fiber product page (32,000 on-net buildings, 1,700 data centers, 99.999% uptime claim)
Zayo wavelengths product page (400G-enabled, 10+ unique routes)
Zayo Dedicated Internet Access product page (100 Mbps to 100 Gbps, 99.9% uptime, 50% augmentation)
Zayo guide to dark fiber (metro vs long-haul, 90% underground long-haul, customer responsibilities)
Zayo network page (route miles, markets, 400G IP PoPs, CAIDA ranking, Zayo Group entities)
Fierce Network, Zayo Waves on Demand (pre-provisioned 100G waves)
Lightwave, Vertical Systems Group 2025 US Wavelength Leaderboard (March 2026)