A system for loading and storing CNG onboard of a ship and for unloading it therefrom comprises CNG loading facilities for loading CNG on board of the ship, CNG storage facilities for storing the loaded CNG on board of the ship at nominal storage pressure and temperature, and CNG unloading facilities for unloading CNG to a delivery point. The delivery point requires the unloaded CNG to be at delivery pressure and temperature generally different from the storage pressure and temperature. Thus, the CNG unloading facilities comprise a CNG heater for heating the to-be-unloaded CNG prior to unloading, and a lamination valve for allowing the to-be-unloaded CNG to expand from its storage pressure to the delivery pressure. A compressor may also be provided to compress CNG that would not otherwise be spontaneously delivered.