Resource assessment as well as characterisation of site climatologies for the design of Marine Energy Converters requires data bases allowing an accurate description of the environmental forcing, especially waves and sea-states, on a high resolution grid. As a support to its research activities related to the development of marine renewable energies, Ifremer is building a specific hindcast data set for the assessment of sea-states climatologies. The main features of this database, built running an up-to-date configuration of the WaveWatch III ® wave model on an unstructured grid extending from the South of the North Sea to the Bay of Biscay are presented here. Attention is given to the parameterization and forcing as well as the specific output data sets and validation processes.