Deep in the world’s oceans and seas lies a network of submarine communication cables connecting continents and regions. This critical infrastructure, owned mostly by international consortia of private telecommunication companies, spans, in total, more than 1.3 million kilometers and handles over 95% of the world’s data. The rise of projects like SpaceX’s Starlink and their use in the war in Ukraine has increased the attention on satellites and space security. However, submarine cables remain a crucial yet underappreciated part of the global communications system. The widespread use of these cables by private individuals, businesses, and government agencies makes their protection a matter of national and international security.

As fighting rages on in Ukraine, the cables in the Black Sea could be in danger of disruption. Accidents have caused damage to the cables in the past, and stepped-up naval activity in the region could raise the risk of vessels accidentally cutting the lines lying on the seafloor. Moreover, deliberate Russian attacks on these cables, either through cyber operations or physical destruction, follow the Kremlin’s modus operandi of targeting critical infrastructure to gain strategic advantage without necessarily delivering decisive blows against its enemies. To ensure regional security in the communication and data spheres, Black Sea states must increase their emphasis on protecting submarine cables, including within the format of the North Atlantic Treaty Organization (NATO) or novel regional frameworks.

Vulnerability of submarine cables

Sabotage operations on critical infrastructure have always been a convenient and effective instrument for the Kremlin, forcing target countries to find ways to prevent, attribute, and appropriately respond to these attacks. A year after Russia annexed Crimea, hackers targeted Ukraine’s power grid, causing blackouts and crippling its control centers. While Ukrainian authorities could not present indisputable evidence implicating the Kremlin, many believe the cyberattack was a carefully orchestrated operation involving the Russian state and cybercriminals. The attacks on Ukrainian energy infrastructure have escalated since Russia’s full-scale invasion began on Feb. 24, 2022, ranging from cyberattacks to shut down energy companies’ systems to military strikes on key facilities, triggering widespread electricity outages across Ukraine and Moldova.

Unlike the attacks on land-based power grids and energy pipelines, the threat to submarine cables is still a hypothetical national security concern as no definitive case of sabotage by a state actor has been confirmed thus far. However, some defense officials, notably the chief of the British Defense Staff, Admiral Tony Radakin, have begun to emphasize the security implications of the cables’ vulnerabilities, especially in the context of the Russian invasion of Ukraine. As suspected in the 2015 attack on the Ukrainian power grid, hackers could theoretically coordinate with adversary states to hide their involvement — thus putting an international hacking group’s April 2022 cyberattack on undersea cables connected to Hawaii in a potentially different light. Furthermore, Russia has been investing in capabilities that would allow specialized submarines to place explosives on the seafloor, physically endangering underwater communication infrastructure. In addition to the Russian navy, the Main Directorate of Deep-Sea Research (GUGI) — known as Russia’s “Deep-Sea Spetsnaz” — can undertake covert operations along the seabed. And NATO officials suspect that GUGI has been increasingly focusing on undersea cable networks in recent years. Notably, in January 2022, Norway detected damage to one of two fiber optic cables off the Svalbard archipelago; suspicions that the cable disruption may have been intentional grew later that year, after a mysterious explosion crippled the underwater Nord Stream natural gas pipeline, an incident that is still under investigation.

Skeptics argue that such concerns are exaggerated, especially since companies that own these undersea networks have been building redundancies to provide different data flow routes in case of a disruption to one cable. Furthermore, of the four Black Sea submarine cables, the only one physically connected to the territories in conflict is the Kerch Strait Cable, which links the occupied Crimean Peninsula with the Russian mainland. Not only is the cable owned by Rostelecom — Russia’s largest telecom firm — but any disruption to communications and internet in Ukraine through sabotage would affect Russian forces on the ground as well.

Admittedly, sabotage on submarine cables alone would not decisively impact Ukrainian resistance, given the above-mentioned redundancies and Ukraine’s access to land-based communication links with the rest of the European continent. However, there is strategic value in cord-cutting. The primary objective of such an attack on submarine cables would be to create confusion and anxiety among the affected populations. The Kremlin could also order sabotage operations on cable networks connected to Ukraine’s allies in North America and Europe specifically to exacerbate the growing war fatigue caused by high inflation and gas prices. Dwindling support from Ukraine’s primary aid and weapons suppliers could provide Moscow with greater leverage and force Kyiv to seek a compromise. Russian President Vladimir Putin recently accepted the possibility of a long war, and though he routinely makes threats about the rising potential of a nuclear war, his reluctance to use nuclear weapons thus far points to the possibility that he would rely more on hybrid, subversive tactics intended to aid his floundering military operation and undermine the support of Ukraine’s allies.

Bolstering submarine cable defense

Other than the Kerch Strait Cable, Rostelecom also owns the Georgia-Russia cable system in a joint venture with Georgian and Danish companies. Stretching across the Black Sea, the Caucasus Cable System, owned by Caucasus Online, connects Georgia and Bulgaria. In the west, Türk Telekom International operates the Black Sea Fiber Optic System (KAFOS), which has landing points in Turkey, Bulgaria, and Romania. In collaboration with these companies, the three allied Black Sea neighbors must invest in tools and mechanisms, such as improving cable repair operations and strengthening cyber and physical threat detection measures at landing sites. New telecommunication initiatives could also help reduce the threat from malicious actors by creating more redundancies to direct data traffic and electricity in cases of damage to other undersea cables or land-based systems. For example, the recently approved Romanian-Georgian-Azerbaijani digital and energy connectivity project will provide a viable alternative to countries like Moldova and Ukraine, which face physical threats to their energy and communication infrastructures.

Yet a multinational security apparatus — whether through NATO or a Black Sea regional defense cooperative — is needed to help private companies successfully defend existing systems and launch future projects. The war in Ukraine has exposed NATO’s deficiencies in preventing and responding appropriately to potential Russian sabotage operations on critical infrastructure. Measures taken by private companies to implement redundancies to limit the impact of individual disruptions will mitigate the risks of widespread internet blackouts. And if NATO states invested more in the defense of these networks, Russia would lose a potential point of leverage against the Alliance.

There has been some — albeit slow — progress to bolster submarine cable defense. In 2017, then-British member of parliament Rishi Sunak (prime minister since October 2022) published a report analyzing threats to the global submarine cable network with proposed recommendations for how to protect them. Among his proposals, Sunak suggested that NATO increase naval exercises and wargames designed to improve protocols and capabilities in response to sabotage of undersea cables. Three years later, NATO defense ministers highlighted the importance of identifying the threats posed to submarine infrastructure, particularly by the Russian navy. As part of this effort to enhance security, NATO tasked Joint Force Command Norfolk (JFC-NF) to monitor and protect these networks in the Atlantic. Introducing a similar mission concept to the Eastern Mediterranean and Black Sea regions could be a productive step in ensuring the security of NATO’s exposed southeastern flank. The next iteration of the Black Sea Maritime Forum, first convened on Feb. 25 of last year, could provide the appropriate platform to advance this issue and discuss solutions among Black Sea states with NATO involvement.

Turkey’s resistance

Regionally, coordinating strategic interests among the Black Sea states, especially with NATO, has always been a challenge. Despite Romania’s vocal support for an increased NATO presence in the region, the lack of enthusiasm from Turkey and Bulgaria has hindered progress toward sufficient Black Sea defense. Turkey’s hesitation may be because of its “middleman” approach to the competition between Russia and the United States. Even as Russian aggression continually destabilizes the Black Sea region, Turkish President Recep Tayyip Erdoğan remains unwilling to fully commit to the West’s punitive stance against Moscow. Turkey’s expanded trade relations with Russia, despite increasing pressure from the U.S. to abide by Western sanctions, and its foot dragging on ratifying Finland and Sweden’s accession to NATO, demonstrate the country’s insistence on prioritizing its own security concerns, even at the expense of hindering a united Euro-Atlantic front.

However, Turkey must not overlook the importance of securing the critical infrastructure networks in the Black Sea, including submarine communication cables, especially as one of them — KAFOS — has a landing point in Istanbul, near the Bosporus Strait. Given Ankara’s interest in minimizing the risk of escalation in the Russo-Ukrainian war, it should contribute to the broader Black Sea region’s underwater domain awareness as well as monitor key vulnerabilities that could be exploited or put at risk by a malign actor — whether Moscow or anybody else. Short of a wider North Atlantic Alliance mission, Turkey should actively cooperate with other Black Sea states, including non-NATO member Georgia, in pursuing their own regional security framework that would include as its mission the protection of submarine cables in the Black Sea.


Hotaka Nakamura is a former intern with MEI’s Frontier Europe Initiative, and has an MA in Security Studies from Georgetown’s Walsh School of Foreign Service.

Photo by Carsten Rehder/picture alliance via Getty Images

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