ABOARD THE LÉ GEORGE BERNARD SHAW-During a recent naval patrol of the Irish Sea, Lt. Cmdr. Maria O'Callaghan pointed to a web of purple lines on her screen, indicating the locations of undersea cables carrying data crucial for internet services and banking transfers.

Around 75% of all trans-Atlantic subsea cables pass through or near the waters around Ireland, where a growing number of suspected Russian shadow fleet vessels now regularly sail. After an increase over the past 18 months, O'Callaghan said, shadow fleet vessels are in the waters nearly every day.

Yet, Ireland's defenses to protect this stretch of the North Atlantic are scant.

The country has eight patrol ships to protect an expanse of water the size of California. It has no long-range military radar, no combat aircraft, no air defenses and no ability to detect hostile submarines.

Ireland allocates 0.2% of its GDP for defense, the lowest proportion of any EU member state even after raising military spending by more than 40% in recent years. The country isn't a member of the North Atlantic Treaty Organization, so doesn't come under the protection of the alliance's mutual-defense pact.

Ireland's defenses are prompting fears among some Western officials and experts that infrastructure essential for Europe and the U.S. is perilously exposed to the threat of Russian interference and sabotage. Russian submarines, spy ships and jets have already been detected in and around the Irish coast and airspace.

"We have sleepwalked into this position where we are in the most difficult security horizon that I can remember. We are essentially defenseless," said David Murphy, an expert on Irish military history at Maynooth University, Ireland. "We don't have the people, we don't have the equipment," he added. "We're 25 years behind the rest of the world right now."

The gap between Ireland and its European peers puts its government in an uncomfortable position, amid a recent wave of hybrid attacks and drone incursions, allegedly carried out by Russia, across the continent. The Kremlin denies involvement.

At a recent European Union defense ministers' meeting outside Dublin, a British warship and submarine-hunting helicopter were deployed at Ireland's request to provide security. British troops on Irish soil have long been anathema, a reminder of the country's 800 years under British rule.

Heading into that meeting, Kaja Kallas, the EU's top foreign and security official, said that maritime security in Ireland "is a great concern for all of us because there are cables that are underneath the sea and that are really affecting the everyday lives of people."

Asked about Ireland's spending, she added that, "member states are making different contributions to defense. It very much depends on whether they feel that the threat is real or not."

Ireland has long promoted itself as a global tech hub with low corporate tax, cutting-edge research and excellent connectivity. It hosts more than 80 data centers, and operational headquarters for tech giants including Apple, Google, Microsoft and Meta Platforms.

"Ireland made a bet on globalization and a world without conflict, essentially, and set itself up as a European hub for primarily American companies," said Elisabeth Braw, senior fellow with the Atlantic Council. "But you also need to make sure that you're able to provide the environment for them when things are not perfect in the world, and Ireland is not set up for that."

Former U.S. national security adviser Robert O'Brien has called Ireland's defense investments "pitiful," saying its lack of radar systems and intelligence networks exposes American tech firms to Chinese and Russian espionage and cyberattacks.

Ireland has cooperated closely with NATO on peacekeeping for decades, but remained outside the alliance. This aversion to militarism has historical roots. Opposition to World War I, and attempts to draft Irishmen into the British army, fueled the Irish revolution, leading to the country's independence. Anti-militarism has since been central to avoiding internal division, and attitudes against rearmament persist.

"Neutrality and opposition to war and empire are absolutely integral to what this country is," said Richard Boyd Barrett, a lawmaker from the left-wing People Before Profit party.

"Russia can barely win a war against Ukraine," Barrett said. "It's preposterous, to be honest with you, that Russia represents any serious military threat."

Yet, Ireland has felt Russia's probing of Europe's defenses, and depended on allies to detect and deter it. U.S. and British forces have spotted Russian attack submarines in Irish waters at least twice since 2022. The U.K. has scrambled jets to deter Russian jet fighters spotted over Ireland's west coast.

In 2024, the Irish navy found a Russian spy ship, the Yantar, loitering over critical internet submarine cables and energy infrastructure, and escorted it away.

In late 2025, unidentified drones were seen flying over Dublin airport during a visit by Ukrainian President Volodymyr Zelensky. Irish Prime Minister Micheál Martin suggested the incident was part of a Russian hybrid campaign.

The number of suspected Russian shadow fleet vessels transiting through Irish waters has increased dramatically in recent months. Some 388 of them passed through the Irish Sea from January to September this year, up from 132 over the same period last year, according to the Irish Naval Service.

On the recent patrol in the Irish Sea, O'Callaghan monitored ships for suspicious behavior, looking for what she called "pattern of life." Similar data cables have been damaged by fishing vessels dragging their anchors.

"As a mariner, we are aware of what is normal and what is not normal," she said. "If they happen to loiter in an area of interest, we go to investigate that and ask the questions."

A 2022 review of Ireland's military capabilities recommended expanding the country's armed forces, and acquiring radars and jet fighters. The government has since increased military spending to roughly $1.7 billion in 2026, and released its first-ever maritime security strategy.

Still, the budget lags behind European peers. Ireland's armed forces number around 7,750 personnel, below its goal of about 9,700. Recommended materiel purchases haven't happened so far.

Irish governments have historically used neutrality to justify low defense budgets. Meanwhile, countries like Sweden and Finland for years remained nonaligned but maintained strong armed forces, said Tobias Billström, who was the Swedish foreign minister during the country's accession to NATO.

For example, "nothing in Ireland's neutrality prevented Ireland from buying primary radars, and that was identified as a gap in February 2022," said Billström, now director of strategy and government affairs with Nordic Air Defence, a tech startup. "Ireland has diagnosed itself accurately but it has so far declined the treatment."