Standardized out-of-service maritime containers can be used as occupation solutions in military deployments. This type of constructions generally experience strong fluctuations of indoor temperatures due to the low thermal mass of its envelope. The implementation of Phase Change Materials (PCM) in the enclosure is a solution to cushion thermal changes and reduce energy demands. In this work, several insulations with PCM in maritime containers are compared as a passive solution to achieve energy savings under different climatic conditions. The results show the capacity of the PCM technology, which must be selected based on the climate where the module is located, in order to reduce both heating and cooling demands. Keywords: maritime containers, insulating, thermal simulation, EnergyPlus, energy savings