Ireland faces rising security concerns over strategic undersea cables

Subsea cables that traverse the ocean floor form the backbone of global communications, carrying a vast majority of international data traffic. These networks facilitate everything from personal messages to trillions of dollars in daily financial transactions. However, these essential links are increasingly viewed as vulnerable targets for sabotage and interference.

Ireland holds a position of outsized strategic importance in this digital landscape. According to the Irish government, roughly 75 percent of transatlantic subsea cables pass through or near Irish waters, effectively connecting North America with Europe. The country is also a major hub for United States technology multinationals, including Google, Microsoft, and Meta, which operate extensive data centers there.

Recent years have seen heightened activity by Russian vessels near undersea infrastructure, fueling fears that cables around Ireland could become targets. In November 2024, the Russian ship Yantar, an oceanographic research vessel described by the UK Ministry of Defence as a spy ship, was monitored in the Irish Sea. It was subsequently escorted out of Ireland’s exclusive economic zone by the Irish Navy.

Tensions escalated in late 2025 when the British government accused the Yantar of directing lasers at Royal Air Force pilots who were monitoring its movements in the North Sea. Earlier, in January 2025, the UK Defence Ministry reported that the vessel had been observed loitering over critical undersea infrastructure in UK waters.

Ireland’s ability to monitor these threats is constrained by its limited defense capabilities. The nation has the lowest defense spending as a share of GDP in the European Union, and its navy lacks submarines. Additionally, Ireland maintains military neutrality and is not a member of NATO.

Senator Tom Clonan, a supporter of Irish neutrality, argued that the country’s long period of peace has led to a relaxation of defense priorities. He noted that successive governments have benefited from a peace dividend over the last three decades, resulting in what he described as a weakness in air, maritime, ground, and cyber domains.

In response to these emerging threats, the Irish government has expanded its naval powers to allow the navy to board and inspect suspicious vessels. Defense Minister Helen McEntee stated in March that protecting against vessels linked to the Russian shadow fleet is a priority. These are often ageing, uninsured tankers used to transport Russian oil and circumvent Western sanctions, a term Moscow disputes as a political fabrication.

Recent incidents in the Baltic Sea have underscored the need for a robust legal framework. In December 2024, a tanker suspected of belonging to the shadow fleet was investigated after damaging cables in the Gulf of Finland. A year later, in December 2025, a cargo ship under the flag of St Vincent and the Grenadines damaged telecommunications cables between Finland and Estonia. A Finnish court convicted the ship's Russian captain and Azerbaijani boatswain of aggravated sabotage, though both denied wrongdoing and the conviction can be appealed.

Daniel Mulhall, Ireland’s former ambassador to the US, emphasized that the country’s geographical position no longer guarantees protection. With 850 US multinationals operating in Ireland, the nation is an integral part of the Western digital economy. He warned that any cyber threat to this economy could target Ireland or make it a collateral victim.

Mulhall argued that ensuring cable safety requires international cooperation. He noted that while no single nation can guarantee absolute security, collective efforts can strengthen defenses against malign actors. He described these cables as the bloodstream of the economy, warning that interference could cause serious trouble.