Based on the research carried out by the authors in the 2000's in the Kurgalsky Nature Reserve and analysis of all previously published information on the plant cover of the protected area, the most valuable coastal, aquatic and semiaquatic biotopes were revealed. To identify the biotopes of high conservation value floristic, geobotanical, geographical and ecotopic criteria were taken into account. The biotopes were characterized based on the occurrence of rare plant communities and rare vascular plant species, including those of European importance. Recommendations for conservation of vulnerable biotopes are given. Noteworthy are coastal habitats - seashores, represented here by meadows, psammophytic grass communities and littoral marshes, as well as underwater biotopes of the Gulf of Finland. Of particular interest are the brackish Lake Lipovskoe and Sileme Canal, as well as the oligotrophic Lake Beloye, with their rare aquatic and semiaquatic plant species and communities. Many threatened plant species very rare in the Leningrad Region are abundant in the Kurgalsky Reserve, and sometimes they are typical components of plant communities. The territory of the Kurgalsky Reserve meets all the criteria of an Important Plant Area (IPA) at the international level. The Kurgalsky Reserve is an area of outstanding conservation value for the Eastern Baltic Sea Region, and it is extremely important to conserve this area.