Floating offshore wind turbines (FOWTs) can be used to exploit the enormous wind energy present over deep waters. Numerous studies have examined the dynamics of FOWTs, but few have focused on validating numerical results with experimental results, particularly for a deep draught FOWT in regions with frequent tropical storms. For this study, we developed a computer code and conducted experiments with a scale model to validate the simulation results. The computer code was first verified by comparing the results with those of the International Energy Agency Wind Task 23. Numerical simulations were implemented in both the frequency domain and the time domain. A comparison of the numerical and experimental results of the scale model in high waves showed good agreement. The flexibility of blades and the tower did not observably affect the motion of the deep draft spar-type FOWT. Therefore, it can be ignored in the preliminary design. The pitch motion of the scale model was within 1°. Therefore, the spar-type FOWT may be an effective power source for regions with frequent tropical storms.