[Purposes] This work contributes to the existing body of research by systematically carrying out numerical investigations on the hydrodynamic characteristics of submerged floating tunnels under the impact of freak waves generated by wave focusing. [Methods] The high-precision finite volume method is used to simulate the governing equations of incompressible two-phase flow. Additionally, a high-resolution numerical wave tank was established. The spring-mass-damping system, which represents the dynamic response of a submerged floating tunnel under wave loads is numerically calculated using the overset mesh technique and the fourth-order Runge-Kutta method. The hydrodynamic characteristics of submerged floating tunnels are systematically investigated by considering the effects of five prominent factors, i.e. wave height, submersion depth, water depth, wave period, and tunnel diameter. [Findings] When subjected to the impact of focused wave, the maximum horizontal load on the submerged floating tunnel is slightly larger than the vertical load. Furthermore, the maximum horizontal displacement is approximately 5 times that of the vertical displacement. [Conclusions] With the increase of the effective wave height, both the hydrodynamic load on the submerged floating tunnel and the structural dynamic response rises gradually. Results show that the influence of the water depth and wave period on the hydrodynamic and structural dynamic response of submerged floating tunnel is very limited. With the increase of the submersion depth, both the wave load on the submerged floating tunnel and the dynamic response of the structure decrease conversely. Another finding is that under the same incident wave conditions, the smaller the diameter of the submerged floating tunnel is, the less the dynamic responses. Therefore, it is believed that the findings drawn from this paper can further enhance our understanding on the damage mechanism of submerged floating tunnel under freak waves.