From undersea cables to underwater drones: the race to secure the ocean floor

Businesses and governments are increasingly waking up to the fact that the future of warfare lies not only in the skies but also under the sea.

With growing concerns about the vulnerability of critical infrastructure such as connecting cables and energy pipelines that traverse the ocean floor, nations and companies alike are pouring significant funding and attention into new technologies intended for underwater use.

This comes amid growing concerns about so-called hybrid warfare, broadly defined as including cyber-attacks, energy sabotage, disinformation and economic pressure, with or without conventional military means.

“It’s the changing threat environment that has brought this issue to the surface,” Chatham House senior researcher Katya Bego told CNBC.

At the same time, rapid advances in artificial intelligence, drones and autonomous technology are enabling new approaches to underwater surveillance, she said.

From autonomous underwater vehicles to sensors attached to undersea cables, governments and military alliances are finding ways to better monitor the infrastructure that supports the global economy.

“Our entire economy is built on this,” Bego said.

In September 2022, several months after Russia began its full-scale invasion of Ukraine, an explosion ruptured the Nord Stream gas pipeline beneath the Baltic Sea. Investigators determined that a pipeline built to transport natural gas from Russia to Germany was intentionally sabotaged.

Bego said the incident, along with damage to undersea infrastructure in other parts of the world such as the Arctic and near Taiwan, has focused governments’ attention on vulnerabilities that received little attention in the post-Cold War decades.

“This has been neglected for quite some time, so it’s going to take a lot of effort to bring this back,” she said.

As of early 2026, more than 1.5 million kilometers of submarine communications cables will be in use around the world, according to Telegeography, a telecommunications research firm that tracks the world’s submarine cable networks.

Alongside communications cables and oil and gas pipelines, a growing network of undersea power cables also connect power markets and transport power from offshore wind farms to shore.

Meanwhile, the widespread deployment of aerial drones during the war between Ukraine and Russia showed how remotely operated autonomous systems can change the nature of warfare. Bego described the marine environment as “the next logical area.”

Defense companies are now poised for that change.

italian shipyard fincantieri announced plans in July to acquire majority stakes in four companies for about 600 million euros ($689 million) to expand its capabilities in underwater and surface drones, marine surveying and undersea communications.

The company is building on more than a century of submarine expertise as it moves from what CEO Pieroberto Forgero calls a “traditional underwater” world to an “unconventional” world that includes mini-submarines, drones and underwater communications. Speaking to CNBC in July, Forgero said underwater telecommunications is “a real enabler of this new ecosystem.”

Forgero believes future surface ships will act as “mother ships,” coordinating a network of vehicles operating on the ocean floor and throughout the water column.

Fincantieri is not alone. Major defense groups including France Thaleshas established businesses across sonar, anti-submarine warfare, mine detection and autonomous underwater systems, as large and small companies alike seek a role in emerging markets operating below the surface.

Germany-based defense technology company EuroAtlas is another company that has set its sights on the potentially lucrative business of undersea defense.

The company has developed an autonomous underwater vehicle called GrayShark that can move into designated areas and carry out missions without continuous human control, said Verinia Kodorian, the company’s chief strategy and partnerships officer.

It is designed to avoid obstacles and follow predetermined instructions when faced with unexpected situations. For example, while inspecting a pipeline, you can identify an object like a mine, report the discovery, and wait for the operator to decide whether to investigate further.

Instead of warships guarding every length of the cable, Kodrian envisions a future where fleets of self-driving cars continually patrol strategic areas on the ocean floor, converging when they sense anomalies.

“It’s virtually impossible to cover the entire ocean,” Kodrian told CNBC. “You just need to know which areas are more interesting to always have visibility into what’s going on there.”

He argued that this is fundamentally a matter of scale, as frigates, submarines, and maritime patrol aircraft are too expensive and scarce to maintain a continuous presence over vast areas where cables, pipelines, and other strategic assets are located.

“There’s a much bigger set of problems in the underwater space domain that haven’t existed before,” he said, adding, “From a mathematical perspective, there’s no way (crews) could be anywhere where these problems are occurring, whether it’s sabotage or some movement from an enemy submarine.”

Self-driving cars aren’t just being developed to monitor infrastructure. Alongside anti-submarine warfare, where submarines target other manned submarines, Kodrian points to the emergence of so-called anti-autonomous submarine (AUV) missions aimed at detecting, tracking and identifying autonomous unmanned submarines operated by other countries.

“What we are building, our non-allies and adversaries are building as well,” she said.

“Other companies are also building autonomous underwater vehicles, so we need to be able to sort out which ones are NATO friends and allies and which are not,” Kodrian said. This increases the potential for further machine-to-machine activity behind the scenes.

But Kodrian doesn’t think self-driving cars will replace traditional submarines or warships. “While it’s not definitive to say it’s just drone-on-drone, we are certainly going to see more drone-on-drone activity until manned force intervention becomes necessary,” she said.

Instead, she expects the Navy to increasingly combine manned and autonomous systems, and interoperability between them will become increasingly important.

Fincantieri’s Forgello said underwater communications were the “real enabler” of the new underwater realm, but Kodrian argued that advances in acoustic and other undersea communications meant the bigger bottlenecks were range and endurance.

Euroatlas is also developing a hydrogen fuel cell version of the GrayShark designed to last up to 16 weeks or 8,000 nautical miles underwater, but the company has not yet demonstrated underwater durability.

EuroAtlas has announced that it has signed a Greyshark contract worth more than €100 million with an unnamed European Navy. Kodrian said the vehicles were not armed, but instead were tasked with surveillance, detection and deterrence.

Despite all the investment and technological advances, fundamental problems remain. That means no one can realistically protect all of the undersea infrastructure.

“I don’t think anyone listening to NATO officials would argue that (we) can protect a network that is more than 1 million kilometers long,” Bego said.

Responsibility for protecting that infrastructure is also becoming blurred. Much of the world’s undersea infrastructure is owned or operated by private companies, which have traditionally dealt with routine maintenance and accidental damage. But governments and militaries will become increasingly involved to protect them from deliberate interference or even outright war scenarios.

Bego said governments are pushing for stronger security measures, which could range from increased surveillance to sensors and burying cables deeper. However, these measures can cost a lot of money, raising questions about who should pay and where ultimately responsibility lies.

As a result, Bego said it would likely require not only regulation but also closer cooperation between governments and infrastructure owners.

While this investment opportunity is attracting companies from both sides of the Atlantic, Bego said Russia and China are also investing heavily in the underwater realm.

“There’s been a huge boom in investing in drones, so there’s definitely more money available because of that,” she says.

However, operating autonomously underwater is much more difficult than in the air. Visibility is poor, communication is difficult, and signals don’t travel the same way underwater as they do in air.

“This is not technology close to the level of drones we see in Ukraine,” Bego said.

“We’re seeing progress, but it’s very difficult,” she added. “The technical hurdles are really quite large.”

Vigo therefore cautioned against viewing autonomous underwater vehicles as a technological solution that can ensure safety on the seabed.

“It helps,” she said. “It’s mainly about deterrence and signaling. It’s good to develop into this area. It’s not a panacea to solve it.”