Coastal aquifers, essential for agriculture, domestic, and industrial water supply, face significant sustainability challenges, particularly in Mediterranean regions, due to the adverse effects of human activities, climatic threats, and natural geological conditions causing salinization. This paper synthesizes findings from studies on three Mediterranean coastal aquifers— the Pleistocene aquifer in the Gaza Strip, the karstic aquifer in Bokkoya, and the MioPlio-Quaternary aquifer in Djeffara of Medenine—highlighting the escalating deterioration due to over-exploitation and arid conditions. It compares the methodologies used in these studies, such as statistical analysis, geostatistical modeling, and groundwater quality indices, to assess groundwater quality and address salinization challenges. This review aims to identify methodological limitations and propose strategies to fill research gaps, particularly in combating seawater intrusion, to enhance the sustainable management of these critical water resources.