Aquaculture is considered one of the fastest-growing food production systems in the world; however, its development is still facing constraints in Morocco, particularly in its marine branch. There is, among others, a great need for integrated site selection to ensure the sustainable development of aquaculture. In an attempt to contribute to the sustainable concept of suitable fish farm sites selection in Morocco, the present work focused on a marine zone, known as M'diq Bay. Based on FAO and GFCM recommendations for the implementation of allocated zones for aquaculture (AZA) and carrying capacity (CC) concepts, site selection was performed in this bay using GIS-spatial multi-criteria evaluation (SMCE) method, aligned with the analytic hierarchy process (AHP) and weighted linear combination (WLC). This procedure allowed us to identify and select suitable areas for fish farming in M'diq bay. In addition, the carrying capacity approach was implemented on physical, productive, ecological, and socio-economic dimensions to define their sustainable levels and harmonious combination. The results showed that seven fish farms are possible to integrate and operate without generating negative effects on the bay ecosystem. The allowed zone for aquaculture was around 84 ha, representing only 0.6% of the bay's total area, with a maximum production level of 2,900 tonnes.