New Arms Race Unfolds on Ocean Floor as Seabed Threats Grow

The shift comes amid growing concern about hybrid warfare, a broad term that can include cyberattacks, energy sabotage, disinformation and economic pressure, with or without conventional military methods. Katja Bego, senior research fellow at Chatham House, told CNBC that the changing threat environment brought the issue to the fore. She said rapid advances in artificial intelligence, drones and autonomous technology are making new approaches to underwater surveillance possible.

Governments and military alliances are exploring ways to better monitor infrastructure that underpins the global economy. “Our whole economy is built on top of this,” Bego said.

In September 2022, months after Russia launched its full-scale invasion of Ukraine, explosions ruptured the Nord Stream gas pipelines beneath the Baltic Sea. Investigators determined the pipelines, built to deliver natural gas from Russia to Germany, had been deliberately sabotaged. Bego said the incident, along with damage to subsea infrastructure in other parts of the world such as the Arctic and near Taiwan, focused governments’ attention on vulnerabilities that received little attention in the decades after the Cold War. “This has been neglected for quite a long time, so it’s quite a lot of catching up to be done,” she said.

More than 1.5 million kilometers of submarine communications cables are in service globally as of early 2026, according to TeleGeography, a telecommunications research firm that tracks global subsea cable networks. Alongside telecommunications cables and oil and gas pipelines, a growing network of subsea power cables also connects electricity markets and carries electricity from offshore wind farms to land.

The widespread deployment of aerial drones during the war between Ukraine and Russia has shown how autonomous systems operated from afar can change the nature of warfare. Bego described the maritime environment as “the next logical domain.”

Defense companies are positioning themselves for that shift. Italian shipbuilder Fincantieri announced in July plans to acquire majority stakes in four companies for around 600 million euros ($689 million) to expand capabilities across underwater and surface drones, marine surveying and subsea communications. The company is building on more than a century of submarine expertise to move from what CEO Pierroberto Folgiero calls the “conventional underwater” world into an “unconventional” one encompassing smaller submarines, drones and underwater telecommunications. Folgiero described underwater telecommunications as “the real enabler of this new ecosystem.” He sees future surface ships acting as “motherships,” coordinating networks of vehicles operating above the seabed and throughout the water column.

Fincantieri is not alone. Major defense groups, including France’s Thales, have established businesses spanning sonar, anti-submarine warfare, mine detection and autonomous underwater systems, as large and small firms seek a role in the emerging market for operating beneath the ocean surface. Germany-based defense-tech company Euroatlas is another company targeting the potentially lucrative business of defending the seabed.

Euroatlas has developed an autonomous underwater vehicle called GrayShark that can travel to an assigned area and carry out a mission without continuous human control, according to Verineia Codrean, the company’s chief strategy and partnerships officer. It is designed to avoid obstacles and follow predetermined instructions when it encounters something unexpected. While inspecting a pipeline, for example, it could identify a mine-like object, report the discovery and wait for an operator to decide whether it should investigate further.

Rather than guarding every mile of cable with warships, Codrean imagines a future with fleets of autonomous vehicles continuously patrolling strategic areas of the seabed and converging when one detects something unusual. “It is virtually impossible to cover the entire ocean,” Codrean told CNBC. “You just need to know which are the areas that are more interesting to have that constant visibility of what is happening there.” She argued that this is fundamentally a problem of scale, as frigates, submarines and maritime patrol aircraft are too expensive and scarce to maintain a continuous presence.