Under the United Nations Convention on the Law of the Sea (UNCLOS) the continental shelf is that part of the seabed over which a coastal State exercises sovereign rights with regard to the exploration and exploitation of natural resources including oil and gas deposits as well as other minerals and biological resources of the seabed. The legal continental shelf (consisting of the shelf, the slope and the rise) extends out to a distance of 200 nautical miles from the coastline, or further if the shelf naturally extends beyond that limit (as it does in Ireland's case).

Where the continental shelf extends beyond 200 nautical miles a State is required by UNCLOS (Article 76) to make a submission to the Commission on the Limits of the Continental Shelf (CLCS). This submission sets out the coordinates of the outer limits of the shelf and is accompanied by technical and scientific data to support the claim. The Commission assesses the limits and data submitted by the coastal State and makes recommendations, which are final and binding.

Ireland's claims to extended continental shelf have been divided into three separate areas:

Zone A: The Hatton-Rockall Area occurs to the west and north-west of Ireland and extends to a distance of more than 500 nautical miles from shore. A maritime boundary between Ireland and the UK in this area was settled by international agreement in 1988. The area is also claimed by Denmark (on behalf of the Faroe Islands) and by Iceland. Informal consultations between officials of the four States on the question of establishing the outer limits of the continental shelf and delimitation issues in the Hatton-Rockall Area have been taking place regularly since 2001. In view of the May 2009 deadline, however, Ireland lodged its submission to the CLCS for this area on 31 March 2009.

Zone B: The area abutting the Porcupine Abyssal Plain is located to the southwest of Ireland and is not the subject of any dispute. On the 25 of May 2005 Ireland submitted information on the limits of the continental shelf that lie beyond 200 nautical miles from the baselines for this area. Consideration of this partial submission began in August 2005 and recommendations were issued by the CLCS in April 2007. The outer limits of the continental shelf in this area were formally established on the basis of these recommendations in 2009 by means of statutory order.

Zone C: This area lies to the south of Ireland on the Celtic Shelf in the area of the Celtic Sea and the Bay of Biscay. Because the area had unresolved maritime boundaries between France, Ireland, Spain and the UK, the four States agreed to make a joint submission to the CLCS. A considerable amount of existing data for the joint submission was assembled and merged from the individual holdings of each country. In September 2005 new geological and geophysical data were also acquired specifically for this submission by a team of scientists from each of the four States during the Breogham cruise using the Spanish research vessel Hesperides. The submission was prepared collaboratively by technical experts from all four States and lodged with the CLCS on 19 May 2006.

Delimitation of this area (approximately 83,000 km) between the four States concerned will now be agreed between them on the basis of applicable principles of international law.

Recommendations on this area were received from the CLCS in April 2009. Information on the CLCS,Article 76 of UNCLOS and the Executive Summaries of the partial submissions of Ireland and the joint submission of France, Ireland, Spain and the UK can be found via the online resource provided.