Purpose <p>A three-dimensional finite element with absorbing boundary model is proposed for the dynamic analysis of soil-caisson foundation interaction, the caisson foundations is embedded in a homogeneous viscelastic half-space. The objective is to evaluate the dynamic impedances and the displacements of caisson foundations under harmonic loading in both the vertical and horizontal directions.</p> Methods <p>The formulation is based on the sub-structuring method, allowing for a comprehensive evaluation of the dynamic response of the caisson foundation in the frequency domain. The soil and caisson are represented by volumic elements and the slab represented by structural plate-type elements. Absorbing boundaries are placed at the boundaries of the model to avoid wave reflection. The horizontal and vertical forces are separately applied to the center of the caisson slab, the displacement responses are obtained by multiplying the exciting force function by the displacement amplitude transfer function</p> Results <p>The numerical results illustrate the dynamic response of the caisson foundations in terms of vertical and horizontal displacements, as well as vertical and horizontal dynamic impedances. The numerical analyses show that both vertical and horizontal dynamic impedances are strongly affected by caisson geometry and soil stiffness. Dynamic stiffness increases with caisson length and soil Young’s modulus, while displacement amplitudes decrease significantly with increasing foundation length, width, and soil elasticity, with reductions of approximately 40–60%.</p> Conclusions <p>This study provides an understanding of the dynamic behavior of caisson-type foundations subjected to dynamic loading, and the results can be used for the optimization of their design in offshore environments.</p>