The EMSO regional facility for the South Adriatic Sea includes two sites, namely the South Adriatic Pit observatory (E2M3A) and the Shelf-slope observatory site (BB and FF) located in the western part of the basin. The E2M3A site is a two mooring system where the main one hosts the surface buoy instrumented with meteorological station and radiometers to collect air-sea interaction measurements, sensors for physical (temperature and salinity) and biochemical (oxygen, partial CO2 and pH) parameters distributed in the mixed layer, telemetry and services. The surface buoy collects the acquired data and transmits them in real time to the on-line server. The secondary mooring line houses an instrumental chain with sensors at different depths for physical and chemical measurements from the sea floor to the intermediate layer. Each of the BB and FF moorings consists of a single mooring of about 100 m that measures physical and geochemical parameters and have the role of intercepting the passage of North Adriatic Dense Water (NAdDW), which forms during the winter between Trieste and Ancona, as it sinks.