By Research Fellow Samuel Bashfield
As the world becomes increasingly interconnected, a battlefield beneath the waves intensifies. Seabed warfare has become a critical domain of modern geotech conflict. With society’s increasing reliance on undersea infrastructure such as communication cables, energy pipelines, and other vital seabed infrastructure, nations are now vying for control of the ocean floor. This new form of warfare threatens the security of global connectivity and could reshape the geopolitical landscape in profound ways.
Seabed warfare encompasses a range of military operations that target undersea infrastructure. These activities include everything from disrupting communication cables and energy pipelines to sabotaging surveillance networks and military installations placed on or near the ocean floor. In an age of unprecedented technological advancements, nations are increasingly aware of the ocean floor’s importance, both strategically and economically. With modern deep-sea technology advancing rapidly, the scope of seabed warfare has expanded from rudimentary cable-cutting and censorship tactics to sophisticated operations that involve surveillance, reconnaissance, and even cyber warfare.
The significance of the seabed has been recognised since submarine cables were laid in the 1800s. During World War I, belligerents understood the value of undersea cables as lifelines for communication. The British, for instance, targeted Germany’s undersea telegraph cables to disrupt communications and gain a strategic advantage. This early form of seabed warfare illustrated the growing importance of controlling these critical lines of communication during conflictual times.
World War II saw a further escalation in seabed tactics, with the Axis and Allied forces working to protect, take over, or sever crucial undersea communication lines. By the Cold War, seabed warfare had become less frequent but more sophisticated, with the United States (US) conducting operations including Ivy Bells, which involved tapping into the Soviet seabed communication cables to gather valuable intelligence. Seabed surveillance systems were deployed to track submarine movements, laying the groundwork for what would become a key component of modern naval strategy.
Recently, seabed warfare has come to the forefront in Europe, particularly in the Baltic Sea. Several high-profile incidents, most notably the 2022 explosions that ruptured the Nord Stream 1 and 2 gas pipelines, highlighted the vulnerabilities of underwater infrastructure. These explosions caused massive leaks and were confirmed as an act of sabotage. While no group or nation has officially claimed responsibility, the incident sparked a web of accusations, primarily between Russia, Western countries, and Ukraine. This attack demonstrated how exposed the global energy and communication networks are to targeted disruptions.
The Nord Stream pipeline incident was just the beginning. In 2023 and 2024, a series of suspected sabotage incidents against undersea cables in the Baltic Sea raised further alarm. As these attacks increased in frequency and severity, the North Atlantic Treaty Organization (NATO) ramped up its naval presence in the Baltic Sea to monitor and protect vulnerable subsea infrastructure and created a Critical Undersea Infrastructure Network. Europe, a key geopolitical hotspot, is fast becoming ground zero for the future of seabed warfare, with growing concerns that similar tactics could spread to the Indo-Pacific.
While seabed warfare instances are hitherto uncommon in the Indo-Pacific in the modern era, rising tensions are starting to put undersea infrastructure on the radar. The Indo-Pacific is home to some of the world’s most critical undersea cables, which connect nations across the Indian and Pacific Oceans. These cables, essential pipelines, and energy routes are indispensable for the region’s economy and security.
As China’s influence in the Indo-Pacific continues to expand, concerns have grown over Beijing’s potential to disrupt or exploit seabed infrastructure to gain strategic leverage. The threat of sabotage or cyberattacks on critical seabed networks is no longer theoretical but a growing reality that could have disastrous economic and military implications.
Indo-Pacific governments are taking note of Europe’s seabed security challenges and are stepping up their own protective measures. Regional partnerships, such as the Quad – comprising the United States, Japan, Australia, and India – have recognised the importance of safeguarding undersea infrastructure. These nations are increasingly focusing on maritime security, with a particular emphasis on infrastructure and submarine cables resilience.
The emerging importance of seabed infrastructure presents both risks and opportunities for nations. The vulnerability of undersea cables, energy pipelines, and other assets makes them high-value targets for adversaries seeking to exploit these resources for military or economic leverage. As a result, strategic decisions will hinge on the ability to monitor, defend, and potentially disrupt undersea infrastructure in critical regions.
One of the most significant changes in modern seabed warfare is the increasing use of autonomous technologies, such as unmanned underwater vehicles (UUVs), for surveillance and defence. These advanced systems provide new capabilities for both protecting seabed infrastructure and for launching covert operations against enemy assets.
Another growing concern is the expanding cybersecurity risks targeting undersea data networks. As nations, corporations, and non-state actors develop increasingly sophisticated ways to exploit weaknesses in these systems, the potential for disruptions in global communications and energy flows grows. Cyber warfare, coupled with physical sabotage, could cripple nations or entire regions in an increasingly interconnected world.
The growing significance of the seabed in global geopolitics means that seabed warfare will only increase in importance in the coming years. To ensure the integrity of undersea infrastructure, nations will need to cooperate on multiple fronts: through enhanced surveillance, improved cybersecurity and strategic defence partnerships.
As the 21st century marches on, it is clear that the ocean floor is no longer a distant and remote frontier but a vital arena for global security. The battle for control of the seabed will shape the future of geopolitics, and nations that fail to address these emerging threats may find themselves at a severe disadvantage, if not disconnected entirely. It is time for Indo-Pacific leaders to recognise the stakes and take action to safeguard this critical domain before the waves of conflict surge.
This article is part of the series—Raisina Edit 2025 and was originally published in the ORF.