Various design loads used in the strength evaluation of ship structures have been introduced currently by classification societies. As most of such design loads have been determined as the standard loads for the sake of convenience, the relationships between the design loads and the sea states actually encountered by ships seem to be poor. Accordingly, it may be difficult to refer and utilize them as the fundamental design concepts for ship designers or the operational guidelines for ship operators. Under these circumstances, authors proposed the practical estimation methods of the design sea states in the 1st report. In this 2nd report, the practical estimation methods of design regular waves resulting in the same level of stresses with that induced in irregular waves under the design sea states are proposed. Furthermore, the practical estimation methods of the design loads such as ship motions, accelerations, hull-girder bending moments and hydrodynamic pressures that are induced under design regular waves are proposed.