Water entry is a complex nonlinear behavior that involves the multiphase flow coupling, which exists extensively in various engineering fields. In the present work, the shear stress transport k − ω turbulence model is imported to close the governing equations. The air–water interface and the six degree-of-freedom motion of the cylinder are defined using the volume of fluid method and the overlapping of grid technology, respectively. A three-dimensional numerical model to simulate the vertical water entry of cylinder under various wind and current velocities is carried out. The results generated from the unsteady dynamic characteristics of the flow field are verified against the published experimental data. A numerical parametric study is subsequently conducted to study in detail the effect of wind and current velocity on translational, rotational, and multipoint pressure characteristics in the process of water entry. The study from the evolution mechanism of cavity and the flow field revealed that the expansion speed and the closure mode of cavity change with the velocity of wind and current, which in turn affects the dynamic motion of cylinder over time and the complex distribution of pressure and velocity field and multiscale vortex structure in the process of water entry.