Global powers are investing heavily in underwater technology, from AI-powered drones to advanced sensors, to protect critical subsea infrastructure like communication cables and energy pipelines from growing hybrid warfare threats. Following incidents like the Nord Stream sabotage, governments and defense companies are rushing to develop autonomous systems for surveillance, detection, and deterrence in what experts call “the next logical domain” of warfare. This emerging underwater arms race pits nation against nation and potentially “machine against machine” in a complex, technologically challenging environment vital to the world’s economy.
The future of global security and warfare isn't confined to the skies; it's rapidly expanding to the ocean floor. Nations and corporations are now dedicating significant resources to advanced underwater technologies, driven by increasing concerns over the vulnerability of vital infrastructure like internet connectivity cables and energy pipelines crisscrossing the seabed.
This heightened focus comes amid the rise of 'hybrid warfare,' a multifaceted threat encompassing cyberattacks, energy sabotage, disinformation, and economic pressure, often blended with conventional military tactics. "It's the changing threat environment that's brought this to the fore," explains Katja Bego, a senior research fellow at Chatham House. Adding to this urgency are rapid advancements in artificial intelligence, drones, and autonomous technology, making sophisticated underwater surveillance and defense capabilities more feasible than ever.
From autonomous underwater vehicles (AUVs) to advanced sensors integrated with subsea cables, governments and military alliances are urgently seeking new methods to monitor and protect the indispensable infrastructure that underpins the global economy. As Bego stresses, "Our whole economy is built on top of this."
The Ocean Depths: The Next Strategic Frontier
A pivotal moment that refocused global attention on subsea vulnerabilities occurred in September 2022. Months after Russia's full-scale invasion of Ukraine, deliberate explosions ruptured the Nord Stream gas pipelines beneath the Baltic Sea. This incident, alongside other damages to subsea infrastructure in regions like the Arctic and near Taiwan, starkly highlighted the neglect this critical domain had suffered since the Cold War era. "This has been neglected for quite a long time, so it's quite a lot of catching up to be done," Bego remarks.
The scale of this challenge is immense: over 1.5 million kilometers of submarine communications cables are operational globally as of early 2026, according to TeleGeography. Beyond telecommunications, a growing network of subsea power cables connects electricity markets and transports energy from offshore wind farms. The effectiveness of aerial drones in the Ukraine-Russia conflict has demonstrated how autonomous systems can reshape warfare, signaling the maritime environment as "the next logical domain."
Defense Giants Dive In
Defense and technology companies are rapidly adapting to this strategic shift. Italian shipbuilder Fincantieri, for example, announced plans in July to acquire majority stakes in four companies for approximately 600 million euros ($689 million), expanding its expertise in underwater and surface drones, marine surveying, and subsea communications. Fincantieri CEO Pierroberto Folgiero sees the company transitioning from 'conventional underwater' operations to an 'unconventional' domain involving smaller submarines, drones, and advanced underwater telecommunications, which he describes as "the real enabler of this new ecosystem." Folgiero envisions future surface ships serving as 'motherships,' coordinating networks of vehicles operating across the water column and seabed.
Fincantieri is not alone. Major defense groups like France's Thales have well-established divisions focusing on sonar, anti-submarine warfare, mine detection, and autonomous underwater systems, as both large and specialized firms compete for a role in this burgeoning subsea market.
The Rise of Autonomous Underwater Drones
Germany-based defense-tech company Euroatlas is a key player in this arena, focusing on the lucrative business of seabed defense. They've developed GrayShark, an autonomous underwater vehicle capable of executing missions without continuous human intervention. According to Verineia Codrean, Euroatlas's chief strategy and partnerships officer, GrayShark can navigate obstacles and follow pre-programmed instructions even when encountering unexpected situations. For instance, while inspecting a pipeline, it could detect a suspicious object, report it, and await further instructions from an operator.
Instead of deploying expensive warships to guard every mile of cable, Codrean envisions a future where fleets of autonomous vehicles constantly patrol strategic seabed areas, converging when one detects an anomaly. She emphasizes that it's a problem of scale: "It is virtually impossible to cover the entire ocean... You just need to know which are the areas that are more interesting to have that constant visibility of what is happening there." Traditional assets like frigates and submarines are too costly and scarce to maintain a continuous presence across the vast critical underwater domains.
Machines Versus Machines
Autonomous vehicles aren't solely for infrastructure surveillance. Codrean highlights the emergence of "anti-autonomous underwater vehicle (AUV) missions." These involve AUVs specifically designed to detect, track, and identify autonomous and unmanned underwater vehicles operated by other nations. "What we are building, so are our non-allies or our enemies building as well," she notes, raising the prospect of intensified machine-on-machine activity beneath the waves. The challenge lies in classifying which vehicles belong to allied or non-allied forces. While Codrean doesn't foresee drones entirely replacing conventional submarines, she anticipates a significant increase in drone-on-drone confrontations, often serving as an initial layer of defense until manned assets are required. Navies, she predicts, will increasingly combine crewed and autonomous systems, making interoperability paramount.
While Fincantieri's Folgiero emphasizes underwater telecommunications as the "real enabler," Codrean argues that the primary bottleneck remains range and endurance, despite advances in acoustic and other subsea communication methods. Euroatlas is addressing this with a hydrogen fuel-cell version of GrayShark, designed for up to 16 weeks underwater or 8,000 nautical miles, though this endurance has yet to be fully demonstrated in real-world underwater conditions. Euroatlas has secured over 100 million euros in GrayShark contracts with unnamed European navies for missions focused on surveillance, detection, and deterrence, as these vehicles are not armed.
The Daunting Challenge of Protection
Despite significant investment and technological leaps, a fundamental challenge persists: it's virtually impossible to realistically protect every mile of seabed infrastructure. "I don't think anyone, listening to NATO people, would pretend that [we] can protect a network of a million kilometers plus," states Bego.
Adding to the complexity is the blurred line of responsibility. Much of the world's subsea infrastructure is privately owned or operated. While these companies traditionally manage maintenance and accidental damage, safeguarding against deliberate interference or wartime scenarios increasingly involves governments and militaries. Governments are advocating for enhanced security measures, including increased monitoring, advanced sensors, and deeper cable burial. However, these measures are costly, sparking debates over funding and ultimate accountability.
The solution, Bego suggests, will necessitate much closer cooperation between governments and infrastructure owners, rather than relying solely on regulation. This investment boom is attracting companies across the Atlantic, with Russia and China also heavily investing in the underwater domain. "There's clearly a lot more money available because of it, because there's just this massive boom in investing in drones," she observes.
However, operating autonomously underwater presents significantly greater challenges than in the air. Poor visibility, difficult communications, and distinct signal propagation patterns make it a tough environment. "This is not technology that's anywhere near the level of the drones we see in Ukraine," Bego cautions. "Progress is being made, but it's just very difficult. Tech hurdles are really quite significant." For these reasons, Bego tempers expectations, emphasizing that autonomous underwater vehicles, while helpful for deterrence and signaling, are not a "panacea" for securing the seabed.
