The numerous ship accidents at sea have usually resulted in tremendous loss and casualties. To prevent such disastrous accidents, a comprehensive investigation into reliable prediction of seakeeping performance of a ship is necessarily required. This paper presents computational fluid dynamics (CFD) analysis on seakeeping performance of a training ship (full scale model) quantified through a Response of Amplitude Operators (RAO) for heave and pitch motions. The effects of wavelengths, wave directions and ship forward velocities have been accordingly taken into account. In general, the results revealed that the shorter wavelengths (λ/L � 1.0) have insignificant effect to the heave and pitch motions performance of the training ship, which means that the ship has good seakeeping behavior. However, the further increase of wavelength was proportional with the increase of RAO for her heave and pitch motions; whilst it may lead to degrade her seakeeping quality. In addition, the vertical motions behavior in the following-seas dealt with higher RAO as compared with case of the head-seas condition. Similarly, the subsequent increase of the ship forward velocity was prone to relatively increase of the RAO for her heave and pitch motions especially at λ/L � 2.0. It was merely concluded that this seakeeping prediction using CFD approach provides useful outcomes in the preliminary design stage for safety assessment of the training ship navigation during sailing. © 2021 PENERBIT AKADEMIA BARU.