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EirGrid High Court Notice Remains On Display In Dún Laoghaire Harbour

21st June 2026
Harbour Posting — A High Court notice concerning EirGrid marine survey operations in Dublin Bay displayed at Dún Laoghaire Harbour. The notice includes a map of the licensed survey corridor. Photo: Afloat
Harbour Posting — A High Court notice concerning EirGrid marine survey operations in Dublin Bay displayed at Dún Laoghaire Harbour. The notice includes a map of the licensed survey corridor Credit: Afloat

A High Court notice relating to EirGrid's marine survey operations in Dublin Bay remains on public display at Dún Laoghaire Harbour.

The notice, dated 14 May 2026, is attached to railings overlooking the marina and contains details of court orders concerning activity within a licensed survey corridor in Dublin Bay.

EirGrid PLC is identified as the plaintiff in the proceedings. The defendants are described in the notice as "persons unknown interfering with the permitted maritime usage in the licensed area under Maritime Usage Licence MUL240010".

The notice includes a chart showing the survey area extending across waters between Dún Laoghaire and Dublin Port. Coordinates defining the licensed area are also published.

According to the court order, the injunction relates to marine survey works being undertaken within the designated survey corridor. The notice states that interference with those operations is prohibited and outlines procedures relating to any equipment or obstructions found within the survey area.

The charted area covers waters regularly used by recreational sailors, fishing vessels and other marine users operating in Dublin Bay.

While dated more than a month ago, the notice remains prominently displayed within the harbour, providing public information on the court proceedings and the extent of the survey corridor.

No further information was immediately available at the harbour regarding the current status of the proceedings.

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Undersea Cables

Undersea cables are vital to Ireland's connectivity, facilitating high-speed internet, telecommunications, and energy transmission. These cables traverse the Irish Sea, connecting Ireland to the United Kingdom and continental Europe, and play a crucial role in global communications.

Submarine Communications Cables:
Ireland is strategically positioned along major transatlantic communication routes. Approximately 75% of transatlantic cables pass near Irish waters, underscoring the nation's significance in global data transmission.
These cables are typically as wide as a garden hose, with the filaments that carry light signals being extremely thin—roughly the diameter of a human hair. They are sheathed in layers of insulation and protection, with cables laid nearer to shore using extra layers of armoring for enhanced protection.

Energy Interconnectors:
In addition to communication cables, undersea interconnectors are being developed to enhance energy security and support the transition to renewable energy sources. The UK has approved the construction of five new subsea interconnector cables to boost the grid's flexibility amidst rising renewable energy. These projects will link the UK with wind farms in Belgium and the Netherlands, and connect England with Germany, Wales with Ireland, and Scotland with Northern Ireland. The cables, with a combined 6GW capacity, are expected to be operational by 2032, increasing the UK's total interconnector capacity to 18GW.

Security Concerns:
The strategic importance of these undersea cables has raised security concerns. Incidents in the Baltics have heightened awareness about the potential risks to subsea infrastructure. Ireland's historical neutrality and limited defense resources have led to calls for enhanced maritime security and defense investments, including modern surveillance technology and international cooperation. The government's response includes participation in EU security projects and collaboration with neighboring countries on maritime security.

In November 2024, a Russian spy ship, the Yantar, was escorted out of the Irish Sea by the Irish navy after it was found patrolling an area with critical submarine pipelines and cables. The vessel's presence heightened concerns due to its proximity to interconnector cables vital for internet services linking Ireland to the UK, operated by major tech companies such as Google and Microsoft.

Regulatory and Policy Framework:
The protection and maintenance of undersea cables fall under the jurisdiction of national governments, with private companies often responsible for their security. In Ireland, the Department of Communications, Climate Action and Environment oversees the regulation of telecommunications infrastructure, including undersea cables. The Irish Naval Service plays a role in monitoring and protecting maritime infrastructure, including undersea cables. Internationally, the United Nations Convention on the Law of the Sea (UNCLOS) provides a framework for the laying and maintenance of submarine cables, recognizing the "freedom of the seas" and the rights of coastal states.

Conclusion:
Undersea cables are indispensable to Ireland's connectivity and economic infrastructure. Given their strategic importance, ongoing efforts are necessary to ensure their protection and resilience against potential threats. This includes enhancing security measures, international cooperation, and adherence to regulatory frameworks to safeguard these critical assets.