In a clear signal of shifting priorities, Ireland has selected French defence firm Thales to supply a towed-array sonar system for its naval forces. This decision reflects growing concern over undersea threats, particularly the vulnerability of critical infrastructure such as transatlantic data cables that lie within Irish waters. While Ireland maintains a longstanding policy of military neutrality, recent events have pushed the government to rethink how it protects its vast maritime zone, one of the largest in Europe.
The new sonar capability represents a major upgrade for the Irish Naval Service. Towed-array sonar systems are highly sensitive underwater sensors that trail behind naval vessels, listening for the distinct acoustic signatures of submarines, drones, and other potential undersea threats. The system, likely based on Thales’ proven CAPTAS models, will provide both passive and active sonar coverage, offering Ireland the ability to monitor the deep ocean more effectively than ever before.
The move follows rising international concern over covert submarine activity, particularly from Russia, in the North Atlantic and near European subsea infrastructure. Instances of suspected espionage ships loitering in Irish waters and increased mapping of undersea pipelines and cables have raised alarms among defence experts. Ireland, though neutral, has been warned that such neutrality does not offer protection against these kinds of hybrid threats. Minister for Defence Simon Harris has acknowledged this vulnerability, pushing for urgent modernisation of Ireland’s maritime surveillance tools.
The Thales sonar system will become part of a broader maritime situational awareness strategy, which includes aerial reconnaissance, radar, and cyber defences. While a formal procurement tender worth around €60 million is expected soon, the Defence Forces have already begun planning how the system will integrate into their fleet. This includes anticipated deployment aboard newly acquired inshore patrol vessels and potential upgrades to existing ships.
Though the investment marks a substantial leap forward, defence analysts caution that technology alone won’t solve Ireland’s maritime security challenges. Operating such advanced systems will require specialised training, dedicated maintenance infrastructure, and ongoing investment in naval personnel. Some argue the decision is long overdue, especially in light of recent incidents that saw foreign submarines operating near Irish shores, requiring assistance from allied navies.
Still, the decision to invest in towed-array sonar is a powerful step toward greater national resilience. It shows that Ireland is beginning to match its maritime responsibilities with the tools needed to protect them, quietly but firmly asserting its readiness in an increasingly complex and contested undersea environment.
