Given the local conditions and capabilities, semi-submersible floating offshore wind turbines (FOWT) appear to be the most suitable concept for harnessing Chile’s substantial offshore wind energy potential. However, compared to Spar or Tension Leg Platforms (TLP) like the proposed in the INF4INITY project, semisubmersibles tend to experience greater motions. Since large motions and accelerations are critical to the survivability of these platforms, it is essential to quantify them during the design process. Consequently, efficient modelling becomes a desired feature on the initial phase of the design, such it allow to optimize the platform following an iterative process. This study evaluates the accuracy and applicability of a numerical model formulated in the frequency domain and based on the Boundary Element Method (BEM). The behavior of a generic semi-submersible wind energy platform under both operational and extreme conditions is assessed, with results compared to experimental data. Analyses include platform motion and mooring forces in both regular and irregular wave conditions. The obtained results reveal the limitations of the numerical model when applying to model the behaviour of FOWT, and methods for improvement are suggested for future investigations.