The action of the ocean＇s waves can be converted into a vertical motion by submerging an opening in the base of a chamber into the sea. The entrained water forces an oscillating airflow through the top of the chamber which vents to atmosphere via an air turbine. An electric generator completes the conversion chain. A design methodology that focuses on the aerodynamic stage which couples the oscillating water column (OWC) and the Wells air turbine will be presented. The turbine＇s most influential design variables will be considered within the context of maximising the plant＇s annual performance within the wave regime.