Renewable energy sources are economical systems suitable for seawater treatment systems wherever there is no electrical grid. This research focuses on finding the best performance of several combinations of these resources (off-grid). The performance compares two alternatives; the first consists of a photovoltaic solar panel, wind turbine, diesel generator, and battery. The second alternative consists of a photovoltaic solar panel, hydrokinetic turbine, diesel generator, and battery. All alternatives are used to drive a small desalination unit with a capacity of 1 m3/h. HOMER software is used to optimize the hybrid renewable energy system and perform technoeconomic analyses. The optimum case from the first alternative combinations consists of a wind turbine with a rated power of 10 kW, diesel generator with a rated power of 4.90 kW, and 20 kW photovoltaic solar panel. This case achieves the minimum electrical power cost of 0.2252 $/kWh and the corresponding minimum water cost of 1.10$/m3. The optimum case from the second alternative combinations consists of a hydrokinetic turbine with a maximum power of 5 kW, diesel generator with a rated power of 4.90 kW, and 2.82 kW photovoltaic solar panel. This case achieves the minimum electrical power cost of 0.1216 $/kWh and the corresponding minimum water cost of 0.56 $/m3.