Oceans have been stages of both war and commerce always, but the threats they currently pose are not as simple as ancient sea warfare. Modern maritime issues are no longer about the fleets colliding in the middle of the open ocean. Instead, navies must now contend with a mix of state and non-state actors, mixed tactics, and assaults on the infrastructure that supports international trade and communication.
Senior naval officials at the 2025 Paris Naval Conference highlighted how complicated this new world has become. Admiral Nicolas Vaujour, Chief of Staff of the French Navy, added that coordination and cooperation are now essential in addressing bolder and more violent challenges at sea. He cited the Red Sea, where Houthi rebels based in Yemen have repeatedly attacked merchant and naval vessels since late 2023, shutting down one of the world’s busiest shipping lanes. “We observe that in the Red Sea, where there is a small militia which has attacked civilian shipping companies, and we must defend that,” Admiral Vaujour said.
The danger isn’t limited to the Middle East. In Europe, deliberate sabotage of seabed cables and pipelines—occasionally attributed to mysterious or so-called “ghost fleet” vessels—has raised the alarm regarding vulnerabilities of strategic underwater infrastructure. The Royal Norwegian Navy Rear Admiral Oliver Berdal noted that nearly all international communications travel via fiber-optic cables along the seafloor, and much of the energy in Europe arrives by way of pipelines, both over and under the sea. Any disruption would have serious economic and social repercussions.
The situation is further complicated when it occurs in global waters, where legal jurisdictions are unclear. Rear Admiral Berdal explained how if a vessel destroys infrastructure outside of a nation’s territorial waters, reactions are late and multifaceted, requiring responses by the vessel’s flag state and complex political negotiations.
Developing global law is an evolutionary process that provides navies with few chances for quick responses. “This very rapidly becomes a very politicized issue,” he said. “So, how much are we willing to get on without necessarily having all of the national legal frameworks in place, because we have not really been tested in this ‘grey zone’ before?”
The solution lies increasingly in cooperation—not just between navies, but with commercial carriers and industry. Royal Danish Navy Rear Admiral Soren Kjeldsen noted that the construction of a reliable maritime image in the future will depend on close cooperation with commercial shipping and owners of critical underwater infrastructure. The lone-navy era is over; maritime security requires responsibility shared with governments and industry.
Vice Admiral Jeffrey Anderson, the Commander of the US 6th Fleet, highlighted the hybrid nature of modern threats, where state and non-state actors utilize irregular approaches in an effort to create chaos. He stressed that the answer needs to be formal NATO institutions as well as nimble multilateral action. That is, any activity at sea must be coordinated and collective.
NATO’s recent Exercise BALTOPS 25 is a practical example of exactly this strategy in action. Lieutenant General John Mead, Deputy Commander Joint Force Command Brunssum, explained that the exercise is not merely a demonstration of power—instead, it is specifically in response to Russia’s attempts to destabilize the Baltic Sea region, particularly by attacking navigation and infrastructure.
BALTOPS 25, the 54th iteration, is complemented by BALTIC SENTRY 2025, an enhanced surveillance activity, to deter aggressive action and enhance the capabilities of NATO to deter. “Exercise BALTOPS 25 will have complementary results to BALTIC SENTRY and thus contribute to NATO deterrence in the Baltic Sea,” said Lieutenant General Mead.
The stakes are higher than ever. UK Royal Navy First Sea Lord Admiral Sir Ben Key commented that the traditional function of navies to protect trade and economic enterprise is more and more threatened by actors who have no maritime heritage. Sea denial, which was once a solely military concept, is today prosecuted hybridically by civilian or non-traditional forces, making it much harder to counter.
Navies must react quickly to threats in the future. This involves constructing more collaborative partnerships with civilians and coalition forces, adopting new technologies for maritime full-spectrum awareness, and developing flexible legal and operational contexts to counter grey zone hostility. The oceans remain vital to global prosperity and security, but protecting them today requires coordination, responsiveness, and strategic depth proportionate to the character of threats they harbor.