Long-haul dark fiber demand is skyrocketing amid ongoing AI data center buildouts, with neoclouds emerging as some of the largest buyers, according to a report from Zayo.
The DigitalBridge-owned firm’s annual Bandwidth Report suggests that long-haul dark fiber demand doubled between 2024 and 2025, with higher capacity counts being snapped up at an “unprecedented rate.”
The 21-page report saw Zayo reveal that new fiber sold tripled over the past year alone, with three of the vendor’s largest hyperscale customers more than doubling their investments, including two separate 864 fiber-count purchases.
Hyperscalers and carriers typically dominate dark fiber investments, with Zayo’s report listing them as accounting for 95% of all long-haul purchases.
But the report suggests so-called “AI-native companies” are eating into the capacity pie, picking up dense counts of both metro and long-haul dark fiber.
Emerging neocloud players are flush with cash and, having shored up their hardware supplies, are now building out their networks. For example, Ciena CEO Gary Smith recently told investors that these nascent vendors were “leaning in on the network” with plans to invest in their own stack.
Zayo’s report points to neoclouds as emerging fiber spenders, with the business having already secured a deal with an unnamed firm for some 8,000 route miles back in April.
“Many of the AI neoclouds and model providers are still getting their feet under them and getting an understanding of how they need to build their backbones to support their growth,” Joda Schaumberg, VP of digital infrastructure sales at Zayo, said. “As this improves and their growth continues, they will continue increasing their bandwidth spend.”
Metro dark fiber is also on the rise per Zayo’s report, growing steadily at a compound annual growth rate (CAGR) of 12% from 2021 to 2025.
The firm said that in a handful of “AI-driven metros,” like New York, Chicago, and Dallas, it’s witnessing up to 20-times higher demand for dark fiber.
“We are seeing the strongest growth in metro markets where data center density, cloud connectivity, and AI workloads are converging,” said Mike Kozlowski, head of product management for metro dark fiber at Zayo. “Demand is increasingly tied to proximity, where data is created, processed, and consumed, which is driving investment into dense metro fiber networks.”