The sea is no longer just a transportation route or an economic resource, but a quiet but important center of strategic competition. Today, the underwater domain has become a major arena for hybrid warfare, and national security is increasingly tied to the protection of critical but largely invisible infrastructure.
Our daily lives depend on the ocean floor. More than 99% of the world’s data is transmitted through submarine communication cables, and national energy security relies on gas pipelines and power interconnections.
Destruction of this infrastructure could halt billions of euros worth of banking transactions and cut off energy supplies for the entire country. This is why underwater defense has become a global market estimated at around 50 billion euros per year.
What is being built: The ecosystem and the drone revolution
The industry’s response to these threats is no longer limited to traditional submarine construction. The focus has shifted to the development of non-traditional systems and dual-use technologies designed to serve both the civilian sector and the military, such as fiber optic and power cable maintenance and installation.
One of the companies operating in this market is Fincantieri Subsea Hub, headed by CEO Pieroberto Forgiello. The group brings together an integrated ecosystem of domestic companies focused on underwater technology. Its purpose is twofold. One is to support the digital transition (the number of fiber optic cables is expected to double over the next decade) and the other is to protect critical infrastructure.
How the DEEP system works
One of the group’s key projects is the DEEP system (Dynamic Ecosystem for Performance Enhancement), a solution for protecting critical infrastructure built around an integrated technology chain.
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Early warning system: The first barrier of sensors installed on the ocean floor detects potential threats by monitoring activity in the surrounding water column.
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Swarm of autonomous drones: When a threat is detected, the system deploys a group of small underwater drones.
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Onboard artificial intelligence: The drone moves toward the threat and, through sensors and artificial intelligence algorithms, identifies the type of hazard in real time, allowing risk mitigation measures to be activated immediately.
Why it’s built: The opacity of hybrid warfare
Geopolitical blocs no longer only clash in public. New forms of warfare often rely on sabotage and other forms of pressure that target critical infrastructure.
Recent incidents, such as the attempted sabotage of the tanker Sea Jewel off the coast of Savona, suspected of being part of Russia’s shadow fleet, have accelerated the realization that commercial ports and maritime corridors are sensitive targets in need of protection.
The opacity of this threat makes continuous monitoring essential. States and private operators will simply not be able to respond once the damage occurs, potentially leading to large-scale digital and energy disruption. Instead, risks should be predicted by integrating undersea monitoring systems with surface drones that patrol inland waters and port access channels.
New frontiers in defense: quantum sensors and underwater wireless networks
Emerging technologies are pushing the boundaries of underwater defense, which until recently belonged to the realm of science fiction.
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Your internet cable becomes your listening device. One of the most innovative developments is DAS (Distributed Acoustic Sensing). The technology makes it possible to measure microscopic changes in tension in standard fiber optic cables used for web traffic, turning transoceanic cables into large underwater eavesdropping devices capable of detecting submarines and divers over vast areas.
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Quantum magnetometer: To overcome the limitations of acoustic sonar in crowded waters, defense researchers are turning to quantum physics. A new quantum magnetometer aboard a drone can detect minute changes in the Earth’s magnetic field caused by the steel hull of a submarine tens of kilometers away.
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Interoperability and underwater wireless communications: As highlighted by the National Hub of the Underwater Dimension, a key challenge for 2026 and 2027 is to create a common European standard that will enable real-time wireless communication between national surface drones, subsea sensors and underwater drones, transforming defense into a shared maritime awareness network in collaboration with NATO.
Toward digital decoupling?
There are also geopolitical risks, moving towards a scenario where infrastructure becomes more fragmented. While Western countries strengthen Mediterranean and Atlantic cables, China is pushing to build alternative digital infrastructure corridors in Asia and Africa.
The future of the underwater realm may not just be military. It is also possible that two separate digital ecosystems will emerge, separated geographically along the ocean floor and protected by swarms of drones ready to guard the invisible borders of underwater cyberspace.
