This paper examines possible demographic trajectories of the Kaliningrad region up to 2045 under conditions of growing geopolitical isolation after 2022. Using the cohort-component method, it models three scenarios that differ only in net migration, while fertility and mortality remain fixed. The results show that migration remains the decisive factor shaping future population size and age structure. Under sustained negative net migration, the region may fall below 1 million inhabitants by 2030 and experience accelerated ageing, with additional implications for the regional economy and defence potential.