This paper describes the circulation of the water masses in the Adriatic Sea. In addition, factors affecting the occurrence of sea currents, their differences, and methods of measurement throughout history are presented. The Adriatic Sea is a relatively shallow and semi-enclosed sea that is deeply incised into the continent with a total surface area of 138,595 km2. It is an elongated basin about 800 km long and 250 km wide, lying approximately southeast-northwest with undeveloped west and very indented east coast. Due to its shape and position, the system of surface currents in the Adriatic is a consequence of the distribution of thermohaline properties. Along the east coast of the Adriatic, there is an incoming current that transports saline mediterranean water into the Adriatic, while less salty water flows from the Adriatic along its western coast. Density gradients are the main cause of general cyclonic circulation, with the incoming current being more pronounced in winter along the eastern and the outflowing current in summer along the west coast of the Adriatic. Measurements of water masses in the Adriatic sea are performed using direct and indirect methods. By direct methods, we can indicated measurements by Ekman and autonomous current meters, and by indirect methods, we can state geostrophic currents.