The ROMS (Regional Ocean Modeling System) hydrodynamic model is run for a domain that covers the Irish waters in the northeast Atlantic. The model has a mean horizontal resolution of 1.9 km and 40 terrain-following vertical layers. The system produces a best estimate of the ocean state once a week and also a daily 3-day forecast. Parameters modeled include: ocean temperature and salinity, sea level, and ocean currents. In addition, two models with a horizontal resolution of 200 - 250m are nested within the larger model to give 3 day forecasts of ocean state for the greater Galway Bay area (Connemara model) and the southwest of Ireland (Bantry Bay model). The ocean forecasts are generated on a 'best endeavors' basis and should not be used for safety critical applications. 7-day forecasts are generated for research purposes and for comparison with measured data. NCEP GFS atmospheric forcing is used and the model is nested within the MERCATOR North Atlantic model. The Marine Institute does not guarantee to make model output available on its web site.