A prefabricated self-supporting module for making building structures, more particularly swimming pools, is provided. The module comprises a matrix made of foamed material and a supporting structure made of metal coupled to the matrix. The supporting structure made of metal may be embedded in the matrix made of foamed material (internal supporting structure) and/or cover the matrix made of foamed material (external supporting structure). Thanks to the provision of the supporting structure made of metal, the module is self-supporting, and it does not need any further reinforcements of reinforced concrete. Thanks to the provision of the supporting structure made of metal, the module can be used for making structural supporting elements such as floors, side walls, and so on. This module can be completely made and finished in the factory, so that the steps to be carried out on the construction site are extremely limited, with consequent economic saving.