Excessive pumping in coastal aquifers results in seawater intrusion where optimal and efficient planning is essential. In this study, numerical solution of single potential solution by Strack (1976) is combined with Genetic Algorithm (GA) to optimize the maximum benefit in a coastal aquifer. Injection wells are added as an artificial recharge to prevent seawater intrusion. The objective is to optimize both pumping rates and locations of injection wells. The model is applied to a previous work by Mantoglou (2003). Two different methods are utilized. First locations and discharge values are optimized, simultaneously. Then, a three-step GA method is introduced where discharge rates and locations are optimized, in an iterative manner.