AWS unveils Fastnet, its first privately built subsea data cable

Jack Loughran Thu 6 Nov 2025

Collected at: https://eandt.theiet.org/2025/11/06/aws-unveils-fastnet-its-first-privately-built-subsea-data-cable

Amazon Web Services (AWS) is planning to build a new 5,000km subsea data cable to connect Maryland, US, with County Cork in Ireland.

The Fastnet cable will be able to deliver over 320 terabits per second, or enough data to stream 12.5 million HD films simultaneously, Amazon said.

Fastnet is expected to be operational in 2028 and will be able to act as redundancy in the event that other undersea cables encounter issues. The installation will help to strengthen the anticipated need for increased data transmission across the Atlantic due to soaring adoption of AI services as well as cloud computing and edge applications.

The system incorporates “advanced optical switching branching unit technology”, which enables data to be redirected to different landing points as network demands evolve. 

Historically, AWS has been part of several consortiums overseeing submarine cable projects that give it a degree of priority access to data transmission across that infrastructure. But Fastnet is the first time the firm has opted to build a cable on its own and could point towards a future where internet infrastructure is owned by a small number of powerful internet giants.

Unlike the consortium cables, AWS will have full control over its capacity and will probably reserve much of this to ensure the reliability of its own services, although that does not stop it from leasing capacity to third parties.

AWS data centres are an increasingly critical part of the internet’s infrastructure: an outage last month showed that the smooth operation of many major platforms and websites depends on them. The day-long outage impacted numerous UK banking services, alongside platforms such as Reddit, Signal, Snapchat, Roblox and Duolingo.

The downtime experienced by UK banks in particular caused some MPs to question why critical financial infrastructure is so reliant on servers hosted in other countries.

Rival tech firms such as Google, Meta and Microsoft have also invested in subsea cables in the past. Google is associated with the largest number, with six fully owned cables and associations with consortiums responsible for a further 15.

“Amazon’s new Fastnet transatlantic subsea cable represents a vote of confidence in Ireland’s digital future, helping to enable the next wave of innovation in cloud computing and artificial intelligence,” said taoiseach Micheál Martin. 

“By linking County Cork to Maryland in the United States, Ireland will become a true gateway to Europe for submarine telecommunications cables. This investment will enhance our global connectivity, reinforce the resilience of critical digital infrastructure, and strengthen our economic competitiveness.”