Undersea warfare is undergoing a strategic transformation. The seabed is now a central theatre of geopolitical competition as global powers seek to secure their economic and national security interests.
Recent events have clearly highlighted this operational reality. Former UK Defence Secretary John Healey recently revealed that the Royal Navy tracked three Russian submarines operating covertly above critical UK data cables and energy pipelines. This activity demonstrates not only how vital infrastructure is increasingly vulnerable to hybrid warfare tactics, but also how our national security relies heavily on our ability to monitor, understand and secure the subsea environment.
In an arena that is becoming increasingly contested and complex, integrating advanced sensors, platforms and secure data networks will be critical to providing the maritime domain awareness required to counter advancing threats.
Recognising today’s threat landscape
In recent years, technological advancements and the growing role of uncrewed underwater vehicles (UUVs) have increased the complexity and importance of anti-submarine warfare (ASW) operations. And the threat is further heightened by geopolitical instability, putting the onus on nations to enhance their ASW capabilities.
But it’s not the only critical component of subsea defence. We’ve previously discussed the importance of critical undersea infrastructure (CUI) such as cables and pipelines – for carrying more than 95% of the internet traffic upon which society relies and providing us with essential energy.
Protecting these assets is a monumental challenge for governments worldwide. Adversaries are increasingly leveraging uncrewed platforms and stealth assets to conduct covert surveillance, mapping and potential sabotage. These operations take place at extreme depths that were previously considered unreachable, over vast areas.
As such, the traditional approach of deploying a single frigate or maritime patrol aircraft to track a hostile vessel is no longer sustainable. Instead, navies require a comprehensive network of connected systems to provide surveillance, gather intelligence, detect threats before they can damage critical national infrastructure, and build a resilient defensive posture.
Transforming naval operations with hybrid fleets
To maintain operational effectiveness in congested subsea theatres, defence strategies are shifting towards 'hybrid fleets'. This strategic transformation integrates crewed platforms, uncrewed vehicles and autonomous systems to enhance operational effect. Subsea warfare no longer exists in a silo. Modern operations require seamless integration across all domains from the seabed to space.
This complex mesh of cross-domain interaction relies on secure communication and allied interoperability. By combining commercial off-the-shelf technologies with bespoke military wrappers, nations can deploy advanced capabilities rapidly and affordably.
This aligns with the core themes of industry gatherings like the recent Undersea Defence Technology (UDT) 2026 conference, which focused on autonomy, application and agility to achieve an advantage through undersea technology.
Putting data at the heart of subsea defence
From CUI protection to advanced surveillance and reconnaissance, the core principles of a credible military response to the subsea threat remain consistent: sense, decide and effect. In the modern underwater battlespace, data is the strategic asset that connects these functions.
It’s the one common critical need. Operators must receive accurate and actionable intelligence at the speed of relevance to make informed decisions. Therefore, the ability to collect data persistently – at a large scale across a wide area – is the backbone to any operation, subsea defence included.
Doing so requires distributed autonomous systems. Mobile, drifting and fixed platforms offer the affordable mass that traditional crewed vessels cannot provide alone, with crewed and uncrewed teaming essential for coherent naval operations.
Furthermore, existing commercial seabed sensors can serve a dual-use role. They monitor cable integrity for industry while providing early warnings of hostile activity for defence organisations, forming a seabed sensing infrastructure that protects both commercial and national interests.
High-volume data processing
Collecting massive amounts of data is only useful if that information reaches operators quickly, securely and in a coherent form. Systems must process data at the edge, on board distributed autonomous platforms, before transmitting it through secure communication pathways. Integrating artificial intelligence and machine learning analytics is crucial to manage this overwhelming volume of information, filtering background noise to highlight significant anomalies.
Going a step further, fusing data from multiple allied sources creates a reliable operational picture. This ensures commanders have the trusted insights required to safely deploy both kinetic and non-kinetic effects safely.
Another consideration when it comes to actionable data is the collaboration/sharing aspect. Sharing intelligence allows allied nations to track elusive targets and respond to threats proactively, thereby enhancing collective security – as long as the agreements and processes are in place to make it possible.
Future-ready capabilities for the underwater battlespace
Ultimately, the protection of critical undersea infrastructure and the wider subsea domain is vital to economic stability, societal function and national security. As geopolitical tensions rise, the need for robust, secure and reliable defence systems becomes absolute.
Defence organisations and governments must therefore continue to invest in data-driven architectures that connect autonomous sensors, data processors and crewed platforms seamlessly.
By embracing advanced technologies, nations can maintain an advantage in the undersea domain. Connecting the subsea domain is no longer a future ambition but a present necessity for global security – one that can’t be ignored.