Abstract: Sea-crossing bridges commonly use dumbbell-shaped cap group pile foundations, which are continuously subjected to wave dynamic actions. A three-dimensional numerical wave flume model is thusly developed using Fluent software, employing the boundary wave-making method to generate waves, with the sponge layers installed at the end of the flume for wave absorption. The correctness of the wave generation, of the absorption, and of the wave-structure interaction simulation methods was validated through simulations of fifth-order Stokes wave propagation and experimental tests on wave-structure interactions with rectangular bridge piers. Using the validated simulation methods, the wave force characteristics of dumbbell-shaped cap group pile foundations were numerically analyzed. The results indicate that the width of the tie beam has a negligible effect on the wave forces acting on the dumbbell-shaped pile cap, and that the wave force can be simplified as that on a single circular cap multiplied by a shape correction factor. As the water level decreases, the group pile coefficients of upstream piles generally increase, while those of downstream piles decrease, with a more pronounced reduction in wave forces along the direction of wave propagation. The presence of the dumbbell-shaped pile cap reduces the wave forces on the piles but significantly increases the overall wave force on the pile group, which should be considered in design. When the design water level is above the pile cap, the wave forces on the cap dominate the total forces acting on the foundation.