Explained: What are the security concerns about Irish coastal waters? What cables are down there?

Eva Osborne

At the end of last year, a new Maritime Security Unit was launched within the Department of Defence.

It was set up to examine the increasing maritime threats to Ireland and create a National Maritime Security Strategy.

But what are these threats? And what are the undersea cables off Ireland's coast responsible for?

Dr Margaret Stanley previously led the office of emergency planning in the Department of Defence and she will head the new Maritime Security Unit.

Stanley has previously said that Ireland's geographic position is part of the reason why this kind of security work is being prioritised.

Ireland's maritime footprint is seven times the country's land area and it is home to the majority of transatlantic data communications.

For example, the AEC-1 cable connects New York with Ireland, landing at Killala, Co Mayo.

It is 5,534km long and has been operating since 2016. The system primarily serves telecommunications providers, cloud service providers, content delivery networks, and enterprises that require efficient data transport solutions.

The safeguarding of undersea cables is a huge priority, as they store everything from banking systems to Tiktok operations. Because of this, they are increasingly attractive targets for military and criminal actors.

Around three-quarters of Ireland's national gas is also imported by undersea gas pipelines.

Speaking on Morning Ireland on RTÉ Radio 1, Dr Edward Burke, assistant professor of the history of war at UCD, welcomed the Maritime Security Unit but said it is a slow start for the National Maritime Security Strategy.

"I think the threats that we see on the Irish seaboard are so intense and obvious, not only to us but to the European Union and to other security partners including the UK," he explained.

"We've seen a lot Russian naval activity off the west and east coast of Ireland. We see Russian spy vessels, we're clearly mapping and surveilling our criminal national infreastructure and associate cables for weaknesses."

The government has said its spending on defence in 2025 is a record €1.35 billion and another increase is expected next year.

Last year, the then Tánaiste and current Taoiseach Micheál Martin said Ireland faces “new and emerging threats” due to its underwater cables which are critical for global communications and commerce.

This infrastructure — on which the global economy now depends — has been suspected of being under the watch of Russian spies.

Martin said that as the majority of transatlantic data communications now run through Irish seas, the infrastructure has critical international importance.

“This exposes us to new and emerging threats, including threats to our offshore infrastructure. We take these threats very seriously,” he said.

“The latest National Risk Assessment for Ireland identified ‘Damage to Critical Undersea Infrastructure’ as one of the country’s strategic risks.

“The potential risk implications for Ireland are stark. Our seas not only contain vital subsea cable infrastructure but approximately three-quarters of Ireland’s natural gas is imported via undersea gas pipelines. As an island nation, we rely on the security of our seas.”