The sustainability of the Floating Net Cage (FNC) cultivation system in Indonesia, including in Lampung Bay, Sumatra, remains largely unknown, even though this fish farming system has become an important source of livelihood for coastal communities. This study aims to evaluate the sustainability of the Floating Net Cage (FNC) cultivation system in three main locations of Lampung Bay, namely Pasaran Island, Hurun Bay, and Labuhan Sawah. The approach used is Rapid Appraisal for Fisheries (Rapfish) with five dimensions of sustainability: ecological, economic, social, institutional, and technological. Leverage analysis is used to identify the attributes that most influence sustainability positions, while Monte Carlo simulations are performed to assess the stability of the analysis results. The results show that Hurun Bay performs best in the institutional and technological dimensions, while Pasaran Island is highly sensitive in the economic and technological dimensions. The robust error value of the Monte Carlo simulation indicated that most dimensions had good yield stability, but some, such as technology in Hurun Bay (0.152) and economics in Pasaran Island (0.117), were highly sensitive. These findings provide a scientific basis for sustainable aquaculture management policies and support the achievement of the Sustainable Development Goals (SDGs), specifically goal 2 (No Hunger) and goal 14 (Ocean Ecosystems).