Amazon unveils Fastnet, a high-capacity subsea cable that can handle 12.5 million HD streams at once

Amazon has announced Fastnet, its first fully owned subsea fibre-optic cable system, marking a major milestone in the company’s global network infrastructure. The cable, which will stretch from Maryland’s Eastern Shore in the U.S. to County Cork, Ireland, is designed to meet surging demand for cloud computing, artificial intelligence, and edge applications powered by Amazon Web Services (AWS).

According to Amazon, Fastnet will boast a total capacity exceeding 320 terabits per second, equivalent to streaming 12.5 million HD movies simultaneously — a figure the company says highlights the project’s unprecedented data-handling capabilities.

Subsea fibre-optic cables form the backbone of the internet, carrying more than 95% of the world’s international data and voice traffic, including critical financial transactions, cloud operations, and government communications. While Amazon has previously participated in shared subsea projects like Jako, Bifrost, and Havfrue, Fastnet is its first independent subsea venture, giving AWS direct control over routing, capacity, and redundancy.

In an interview with CNBC, Matt Rehder, vice president of core networking at AWS, emphasised the importance of subsea connectivity to the company’s global operations. “Subsea is really essential for AWS and for any connectivity internationally across oceans,” he said. “Without it, you’d have to rely on satellite connectivity, which has higher latency, higher costs, and simply can’t meet the throughput requirements our customers expect.”