This paper presents the stability analyses of a tri-columnar concrete semisubmersible floating platform tailored for a DTU 10 MW wind turbine. The stability of the platform is investigated using SESAM software, focusing on the influence of side pontoon diameter, height, spacing, and the width of the bottom horizontal tanks. An analytical model is employed to examine the combined impact of these factors on the stability and their respective sensitivities. Results indicate that the diameter of the side pontoons exerts the most significant influence on the stability of the platform. Furthermore, free decay simulations validate that the natural periods of the platform are adequately separated from typical first-order wave periods, ensuring compliance with design requirements.