Information on seagrass in the Russian section of the Baltic Sea – Sambia Peninsula, Curonian Spit, and Gulf of Finland (water area of Kaliningrad and Leningrad regions) is generalized based on a recent survey, literature search, and study of herbarium samples. Seagrasses are found in the emissions of most of the coast of the Kaliningrad region, but they are extremely few. All discovered seagrasses belong to one species – Zostera marina L. In the absence of an opportunity to distinguish the emissions of Zostera marina brought in by currents from other regions of the Baltic Sea from local emissions, the possibility of the presence of a small number of single individuals of this species in the seawater area of the Sambia Peninsula and the Curonian Spit remains. Specimens of Zostera marina brought in by storms from the western part of the Baltic Sea, as well as an individual found during diving studies in 2009, can take root and form small meadows in the future, provided they are protected from surf waves and a stable substrate, settling with the help of vegetative shoots. Poorly rooted seagrasses can also be washed ashore. The mobile sandy ground found in most of the study area may be the reason why seagrass plants do not form stable communities. In the Russian section of the Gulf of Finland, seagrass had not been recorded. Probably, they occur in small numbers in its northern part.