This paper examines the environmental aspects associated with the development of Ireland’s Atlantic Marine Energy Test Site (AMETS), which is being developed off the west coast of County Mayo near Belmullet by the Sustainable Energy Authority of Ireland (SEAI) in conjunction with its project partners, ESB International (ESBI), the Marine Institute and TONN Energy. The test site will provide a grid-connected national test facility, at which full scale pre-commercial wave energy converters (WEC) could be deployed during their final stages of pre-commercial development. It will facilitate small arrays of up to five WECs each. It is an integral component of Irelands Ocean Energy Strategy and will facilitate testing and validation of wave energy converters in an open ocean environment. It will be operational for a period of up to twenty years and will be decommissioned thereafter. The results of a year long environmental assessment of the use of the site by birds and marine mammals together with details of subtidal, intertidal and terrestrial habitats are presented. The test site will provide a facility, not only for testing WEC’s, but also for gaining experience on how to develop wave farms for electricity generation, what environmental impacts are associated with such developments and how electricity generated from WEC’s can be integrated and connected to the existing electricity network.