Shipbuilding is one of the most complex production systems in the manufacturing industry because of the incredible variety of parts and highly complex processes. However, production plans are currently prepared manually depending on the experience of expert workers. In this paper, a production planning method based on shipbuilding process simulation is proposed for use in actual shipyards, which simultaneously satisfies the needs of both production managers, who require on-time delivery plans, and field workers, who aim to minimize waiting time and improve operating rates. Specifically, the authors developed a hybrid method that combines backward and forward simulation for planning front-loading to meet deadlines and reduce waiting time. In the case study, the method was applied to a sub assembly conveyor line in an actual shipyard to demonstrate the validity and feasibility of the simulation results.