The article presents the results of the study of dynamics of the coastline of the western part of Kotlin Island, where in the early XVIII century naval fortress Kronstadt (now the district of St. Petersburg) has been founded. Over the past 300 years, the Western part of the island has been dominated by abrasion (scour) processes. According to the comparison of multi-temporal aerial and satellite images, the average rate of abrasion of the territory for the period of 1939-2005 is estimated at 1120 m2 per year, and for the period of 2005-2016 is estimated at 4512 m2 per year. The rate of linear abrasion of the island, calculated using historical maps and other evidence, estimated at 12 m per year from the beginning of the XIX century and 16m per year since the beginning of the XVIII century. A significant (more than 2.5 times) increase in the rate of abrasion of the coast in the last decade compared to the second half of the XX century can be explained by the increase in the number of storms, with surge in ice-free autumn-winter period. Observations on the permanent key plots in the natural protected area «West Kotlin», carried out since 2012, allowed to study the processes of landscape dynamics in coastal areas subjected to the processes of abrasion and accumulation. On the areas with land increase, overgrowing successions take place with the formation of grass, shrub communities and stands of small-leaved trees (especially aspen). At the prevailing areas of abrasion occur abrupt changes in ground vegetation cover of forest, shrub and bog communities, until its destruction by being covered by sand. Forest stands, including black alder (Alnus glutinosa) groves, are also exposed to abrasion but have a much higher sustainability. The results of the research allow predicting the dynamics and evolution of landscapes in the western part of Kotlin Island and planning measures to prevent unwanted coastal processes and preserve the valuable natural territorial complexes of St. Petersburg.