Wave energies, and in particular oscillating water column (OWC) systems, represent a promising source of renewable energy, offering many advantages in today’s energy transition. They play a key role in diversifying green energy sources and securing power grids by complementing other renewable sources. In this context, a CFD numerical analysis is conducted in this study to predict the interaction between waves and a semi-submerged oscillating chamber. CFD is indispensable for the development and refinement of OWC wave energy converters. The used turbulence closure model is of the standard k-epsilon type. The effect of chamber shape on water and air flow performance has been performed. The simulation focuses on the effect of classical and spherical shapes on the structure’s hydraulic and aerodynamic characteristics. A nearly 15% improvement in average outlet flow velocity is observed using the spherical_R2 geometry.