The research on water entry dynamics is essential for a wide range of polar exploration applications. In particular, investigating the cavity evolution and motion characteristics of structures during water entry in complex environments, such as ice-covered waters, is crucial for the design of vehicles and equipment operating under these conditions. In this study, numerical simulations and experimental methods were employed to investigate water entry under various ice-covered environments, including ice holes of different sizes, floating ice with varying distributions, floating ice with different particle sizes, and ice plates. Recommendations on water entry modes and entry velocities for the deployment and operation of marine engineering equipment in polar regions are also proposed. This research aims to deepen the understanding of fluid–structure interaction dynamics during water entry under ice-covered conditions and to provide valuable guidance for the design and optimization of vehicles and structures operating in polar and ice environments. Future work will focus on incorporating ice fragmentation effects into numerical models to further explore dynamic interactions in realistic scenarios.