Isolated water-energy microgrids (IWEMGs) can consist of non-traditional renewable energy sources, water generators, demands, and water and energy (WE) storage systems. This technology solves the for generating well-being in remote or isolated areas. This paper uses game theory to present a solution to an IWEMG resource management, planning, and dispatching problem, considering the water-energy nexus through a storage element. The players are consumers, producers, or prosumers who compete in a non-cooperative game (Cournot competition) by water and energy transactions, allowing them to exchange resources via an IWEMG. Each player’s internal production, storage, and demand elements are modeled mathematically. Then, an optimization problem is formulated for each player based on its role in the IWEMG. Complementary models are used to simultaneously solve these problems. The formulation is evaluated through a case study, using estimated parameters of demand and generation of water and energy from a small rural community, known as Rancher´ıa, in La Guajira, Colombia. The model is implemented and solved in the GAMS software. The results of the case studies demonstrate that IWEMG’s components are capable of supplying the WE needs of the players over a seven-day period. Similarly, an analysis of WE tradings is performed, in addition to the net benefits obtained and its performance regarding the demand curve parameters.