This dataset consists of significant wave height, peak wave period, second moment wave period and nautical wave direction. The dataset is a gridded dataset, with grid resolution of 1.85 km. It covers the entire Irish Sea area, with a precise range -2.7 degrees longitude to -7 degrees longitude and from 51 degrees latitude to 56 degrees latitude. The data are hourly averages and cover the period from 01 January 1996 to 01 January 2007. The wave parameters generated by POLCOMS-WAM were used as input conditions into a coastal processes and sediment transport model which looked at the response of the north Liverpool coastline to extreme flooding events. The dataset was generated by the Proudman Oceanographic Laboratory Coastal Ocean Modelling System coupled with the Wave Modelling model (POLCOMS-WAM) as part of the Natural Environment Research Council (NERC) CoFEE project which ran from April 2007 to September 2010. The dataset consists of 132 data files in Climate and Forecast (CF) compliant NetCDF format.