Global internet and artificial intelligence expansion increasingly depend on an often overlooked piece of infrastructure underwater communication cables.
More than 95 percent of international data and voice call traffic flows through nearly a million miles of subsea cables, carrying everything from government communications and financial transactions to video calls and streaming media.
“The growth of AI and data intensive services is only increasing the importance of subsea cables,” said Alex Aime, vice president of network investments at Meta.
“People often think about AI as compute and data centers, but without the connectivity linking those centers, they are just expensive warehouses.”
Subsea cables date back to 1850, when the first commercial telegraph cable connected Dover, England, and Calais, France. Telephone communications later relied on coaxial cables, and today fiber optic technology powers the global internet.
The market has evolved, with webscale companies like Meta, Google, and Amazon now representing roughly half of the subsea cable market, according to Paul Gabla, chief sales officer at Alcatel Submarine Networks, the world’s largest subsea cable manufacturer and installer.
“About ten years ago we saw a new category emerge with webscale players demanding dedicated connectivity to meet growing data needs,” Gabla said.
As AI driven applications require increasingly large and fast data transfers, investment in subsea cables is surging.
Telecommunications data firm TeleGeography forecasts investment in new cable projects to reach approximately $13 billion between 2025 and 2027, nearly double the $6.5 billion invested between 2022 and 2024.
Meta’s Project Waterworth, announced in February, aims to lay a 50,000 kilometer cable linking five continents, making it the world’s longest subsea cable project. Meta will be the sole owner of the multi year, multi billion dollar project.
Amazon has also launched Fastnet, connecting Maryland’s eastern shore to County Cork, Ireland, with capacity exceeding 320 terabits per second, capable of streaming roughly 12.5 million HD movies simultaneously.
“Subsea infrastructure is essential for AWS and global connectivity,” said Matt Rehder, Amazon Web Services vice president of core networking. “Satellite links can help, but latency is higher, costs are greater, and the capacity needed for AI and global internet traffic cannot be matched.”
Google has invested in over 30 subsea cable projects, including Sol, which will connect the US, Bermuda, the Azores, and Spain. Microsoft has similarly expanded its subsea footprint, highlighting the strategic importance of direct oceanic connectivity for major tech providers.
Matthew Mooney, director of global issues at cybersecurity firm Recorded Future, noted, “You’ve seen huge growth in submarine cables over the past 20 years, driven by an insatiable demand for data.”
Subsea cables carry the bulk of global communications traffic, far outpacing satellites in both capacity and reliability. While one damaged cable can disrupt connectivity for entire regions, redundancy built into global networks mitigates long term outages.
In 2022, Tonga’s only subsea cable was severed by debris from an underwater volcanic eruption, leaving the island isolated from the internet.
In September, disruptions in the Red Sea affected Microsoft Azure users in Asia and the Middle East, though re routing minimized outages.
Experts say most damage is accidental, often caused by fishing operations or anchors, but intentional sabotage has become a growing concern.
For coastal communities and small nations, subsea cables are a lifeline. “When our only cable was cut, everything from banking to communication stopped,” said Lani Tupou, a telecommunications official in Tonga.
It highlighted how vulnerable even a small nation is to disruptions far beyond its control. Industry engineers emphasize the need for investment and maintenance.
“Subsea cables may be out of sight, but they are the backbone of global connectivity,” said Gabrielle Martinez, a network engineer based in Miami. “Ensuring their security and reliability is critical as AI and cloud services expand.”
With AI models becoming more computationally intensive and data center networks growing, the demand for subsea cables is likely to accelerate.
Analysts expect continued private investment from major tech firms alongside international partnerships to increase network resilience.
“As data volumes grow exponentially, the next decade will likely see unprecedented cable deployment,” said Aime. “The internet, and AI in particular, cannot function without robust subsea infrastructure.”
Underwater cables, often invisible to the public eye, have become central to global AI development and internet functionality.
As investment surges and projects like Waterworth and Fastnet come online, these subsea arteries will shape connectivity, economic activity, and technological innovation across continents.
The challenge remains ensuring these cables remain secure, reliable, and capable of supporting a rapidly digitalizing world.