Background The posidonia plant (Posidonia oceanica) is a seagrass species found only in the Mediterranean on sandy substrates down to a depth of 35-40 metres. Besides stabilising the sea bed and contributing to the cleanliness of the water, it also has an essential role in oxygenating the water and providing a refuge, feeding and breeding area for a large number of species. In the Balearics, the posidonia plant has been threatened by unregulated human activity such as illegal trawler fishing, random mooring of pleasure boats, construction, pollution, and to a lesser extent competition with invading alien algae species (Caulerpa taxifolia). A considerable proportion of the Balearic coast has been proposed for inclusion in the Natura 2000 network due to the presence of posidonia beds and other species of Community interest. Objectives This LIFE project was established to strengthen the viability and biological richness of posidonia meadows in the archipelago. It also aimed to improve the conservation status of other species of Community interest including bottlenose dolphin (Tursiops truncates), loggerhead sea turtle (Caretta caretta), Audouin gull (Larus audouinii) and European shag (Phalacrocorax aristotelis). Results Notwithstanding some management and coordination problems, the project succeeded in accumulating important information about the marine sites targeted and the relevant species for which those sites were designated as SCIs. A number of valuable management tools have been created and legal mechanisms have also been adopted. An outcome from the LIFE work is a new regulation controlling mooring areas in 7 SCIs. Other results include: Creation of 3 new marine reserves and associated monitoring teams at Cala Ratjada (jointly managed with the Spanish Ministry), Migjorn and Malgrats; Production and approval of 14 comprehensive management plans for marine SCIs; Collation of detailed data regarding factors affecting the posidonia and its biological status in the Balearic Island SCIs; Collation of detailed data on factors affecting the European shag, the Audouin gull, the bottlenose dolphin and the loggerhead sea turtle and their population situation in the Balearic Islands; Research and drafting of a Conservation Plan for loggerhead sea turtle and bottlenose dolphin (waiting for official approval); Research and drafting of Recovery Plan for Audouin gulls and Mediterranean shags (Phalacrocorax desmaresti) (waiting for official approval); High quality GIS mapping of all the marine SCIs; Establishing a network of volunteer scuba divers to monitor posidonia meadows and the presence of invasive species such as Caulerpa taxifolia and C. prolifera; and A broad awareness raising campaign, reaching thousands of local residents and tourists, ran successful public exhibitions on the 3 main islands. These LIFE funded activities now provide the Balearic Government with the core set of conservation tools required to manage the Posidonia meadows in an appropriate and sustainable manner. The methodology applied is considered to offer good transferable opportunities for other Natura 2000 marine sites, particularly those that would benefit from effective mooring regulations.