ABSTRACT Liquefied natural gas (LNG)-fuelled ships provide a good option for the air pollution problem. However, safety and reliability have to investigate in the design process. A hypothetical LNG-fuelled ship model is used as the target ship. The gas explosion parameters include the gas cloud volume for determining the gas cloud size and the gas cloud centre of gravity for specifying the gas cloud position and ignition point. Previously reported gas dispersion results are utilised to establish these parameters regarding both frequency and physical data. The Latin hypercube sampling is used to generate 50 gas explosion scenarios. The blast overpressure of vapour cloud explosion (VCE) is simulated by the ExSim computational fluid dynamics (CFD) code, and software validation is provided. Finally, the gas explosion frequency can be compiled with blast overpressure to produce the exceedance frequency diagram. Subsequently, this diagram can be used to determine the design accidental loads under VCE.