A significant development of offshore wave power is planned in the future, and its impact on the marine environment is unclear. Solid structures placed on the seabed create new habitats and function as artificial reefs for marine organisms. In this study we investigated the artificial reef effect and fouling impacts on offshore wave power devices deployed at the Swedish west coast. Here, buoys acting as point absorbers on the surface are connected to generators anchored on concrete foundations on the seabed. We studied the influence of surface orientation of the wave power foundations on epibiotic colonisation, and made in situ observations of micro-habitat use by fish and crustaceans over four years of submergence. We also examined fouling assemblages on buoys and calculated the effects of biofouling on the energy absorption of the wave power buoys.