Ocean stores a huge amount of energy and ocean current energy can be a viable source in future. In this article, an axial marine current turbine has been optimized to enhance its power coefficient through numerical modeling. The blade pitch-angle and number of blades are the design parameters chosen for the analysis to find the optimal design. A commercial code for CFD simulations with in-house optimization code was used for the analysis. It was found that, changing the blade pitch-angle and reducing the number of blades can improve the turbine’s coefficient of power. This is due to increase in lift and reduction of losses caused by turbulence near the downstream of the turbine. The article presents flow-simulation difficulties and characteristic curves to identify the differences between the actual and optimized turbine. The detailed flow physics is discussed and pictured in the post processed plots.