The goal of this paper is to investigate the influence of wave-current interaction on a tidal turbine. Experiments at the Norwegian Marine Technology Research Institute (MARINTEK, Trondheim, Norway) have been carried out, and a computational fluid dynamics (CFD) analysis has been performed to enhance the understanding of the wave-induced loads on the tidal turbine rotor. These loads are known to be the governing forces, and it is, therefore, of great importance to predict them accurately. The CFD results are found to be trustworthy with calculated values close to experimental data. In addition to the wave-induced forces, the wake characteristics and wave influence on the wake are investigated. CFD is a powerful tool if used properly, but it is computationally expensive, especially when dealing with complex geometry such as a tidal turbine blade. A high-performance computer (HPC) has been used to carry out the transient CFD wave-current simulations to obtain reliable results within reasonable time.