This dataset contains information on the abundance of benthic infauna species from sediment grabs collected from the South East Mourne Coast off Co. Down (Northern Ireland). This survey is part of a large project called INIS Hydro which aims to provide high resolution seabed baseline data for the coast of Ireland, Northern Ireland and Scotland using multibeam echosounders and grab samples for ground truthing. This survey was carried out in February 2011 on the RV Corystes using a 0.1m2 day grab. There were 47 grab samples taken in which infaunal analysis, Particle Size Analysis (PSA) and and Carbon & Nitrogen (C&N) analysis were carried out. The most abundant species found was the brittle star Amphiura filiformis and the most frequently recorded was the polychaete Lumbrineris cingulata.