The realisation that the world’s oceans play an important role in climate regulation and many territory activities, notably food production, coupled with economic changes and the rapid advancement in ocean technology have seen a shift in the perception of the importance of marine resources. This increased focus on marine resources means that governments and policy-makers require accessible and reliable information regarding the role of the marine sector. This information may then be used to formulate new environmental and economic policy measures. The aim of this paper is to define, describe and quantify the value of the marine sector in Ireland. This paper outlines a methodology that provides a robust analysis of the Irish marine sector for 2007. It was found that in 2007 the Irish marine sector contributed €1.44 billion in GVA to the wider Irish economy and employed over 17,000 individuals in full time equivalents.