Posidonia oceanica (L.) Delile, a flowering plant endemic to Mediterranean Sea, is a very important part of marine ecosystem. It inhabits the infralittoral zone where it forms dense meadows which are for the large number and diversity of creatures in them and for geological and biological impact on the enviroment called Posidonia oceanica biocenoses. As a primary producer, along with algae and phytoplankton, Posidonia is important for producing large amounts of organic material and oxygen and as such represents a fundamental part of marine food chains. Because of the threat human activities (pollution, fishing, anchoring, construction) present to posidona, it is very important to document its distribution which is than used to establish conservation measures for certain areas, thus protecting that essential component of the marine ecosystem. The first step in this is mapping the existing meadows as a way of obtaining the basic data for each following research and activity. This work deals with the most common methods of mapping posidonia, their advantages and disadvantages and working principle of each. Indirect methods, which include satellite imagery, aerial photography and sonar mapping are used to get a general picture of relatively large areas of interest. Direct methods such as diving with scuba equipment along the transect, snorkeling in very shallow areas, using remotely operated vehicles (ROV) or some other method to make an underwater video recording and airborne laser mapping enable scientists to gather detailed information on smaller seabed areas. Also, such methods are necessary to calibrate and confirm the results of indirect methods.