Numerical simulation of the ship motions in regular waves with changing wave direction is carried out. An in-house structured CFD solver [1] which is capable of the overset-grid method is used. The governing equations are 3D RANS equations for incompressible flows. Artificial compressibility approach is used for the velocity-pressure coupling. Spatial discretization is based on a finite-volume method. An interface capturing method based on a single phase level set approach is employed to simulate the free surface flow. Ship motions are determined by solving motion equations, and the motions are strongly coupled with the governing equations. The computational domain is deformed under the criterion of the distance from the ship hull. Regular waves are generated in the regions inside of the computational domain. The wave direction is determined with changing the regions which generate the regular waves. The present method is applied to the case in CFD workshop Tokyo 2015[2]. The ship type is the container hull with the rudder, and the ship motions are three degree of freedom, the heave, pitch and roll motions. Figure 1 shows the instantaneous view of the free surface. The wave pattern indicates the direction of the waves, and the disturbed wave due to the interactions between the incoming waves, ship and its motions can be found. Figure 2 shows the comparison of the amplitudes of the pitch motion. Present results show agreement with the measured data and indicate similarity with the other computed results. The effectiveness of the present method is shown through the comparisons with the experimental and computed results.