In the present paper, the mooring system of an offshore aquaculture platform is designed and optimized, applying a shallow water mooring system design methodology which combines the Non-dominated Sorting Genetic Algorithm-II (NSGA-II) and the cable–platform coupled model. One mooring design is first given using the proposed methodology. Two reference mooring systems are modified based on an NSGA-II design, and AIP criteria and expertise. The hydrodynamic performance of the offshore aquaculture platform with these three mooring systems is compared via use of a potential flow time–domain numerical simulation. A physical model-scale experiment is carried out to validate the numerical coupled model. Both numerical and experimental results confirm the effectiveness of present model. The comparative analysis shows that the mooring system designed using NSGA-II can provide a relative radical solution compared to the other two mooring designs when considering a limited budget.