This study aims to investigate water quality management in the cultivation of mud crab using an apartment system at the Balai Besar Perikanan Budidaya Air Payau (BBPBAP) in Jepara, Central Java Province. Cultivation media, media preparation, crab selection, feeding management, and water quality management are the main focuses of this research. The research method employed includes direct observation and the collection of both primary and secondary data. The gathered data are analyzed descriptively to provide clear and detailed information. The results indicate that the apartment system serves as an effective cultivation medium for mud crabs with proper water quality management. However, variations in water quality parameters such as temperature, salinity, dissolved oxygen (DO), and pH affect the growth and survival of crabs. In conclusion, optimal water quality management is crucial for the successful cultivation of mud crabs using the apartment system.