Abstract <p>The article reveals the mechanisms of adaptation of food markets of Russia’s western borderland to the integration and disintegration processes that have taken place on the external and internal borders of the Eurasian Economic Union since 2014. Based on a case study of Kaliningrad and Smolensk oblasts, the authors identified changes in the regional food base in the context of active import substitution, assessed changes in food preferences of the population, as well as the role of cross-border practices in meeting the needs of the population for food products. Based on an analysis of regional and federal statistics and field research, it was possible to establish that against the background of active investments in the agriculture and food production, three parallel processes were taking place: spatial contraction of agricultural production, expansion of its production capacity by large agricultural holdings in strictly defined zones (around regional capitals and important transport arteries), and expansion of holdings into selected peripheral areas with the lowest land costs. Despite the commonality of processes, the results in the agriculture and food production and activity in obtaining state support in Smolensk and Kaliningrad oblasts are fundamentally different. A visual inspection of retail outlets, discourse analysis, and representative surveys of the population led to the conclusion that import substitution only partially provided regional food markets in both regions with raw materials and final products, since most holdings are oriented towards meeting demand in high-margin markets within and outside the country. Food markets in border regions, on the one hand, are more vulnerable to integration and disintegration processes, and on the other hand, they have a wider range of choices and opportunities for cross-border shopping trips. However, empirical data obtained by sociological methods show that the widespread idea of high cross-border mobility of the population of border regions is greatly overestimated. The populations of Smolensk and Kaliningrad oblasts are similar in their level of mobility and conservatism with respect to purchasing goods from specific manufacturers in a suitable price segment. The “network” (through intermediaries) penetration of “sanctioned” goods into Kaliningrad oblast covered a significantly larger share of the population than those who directly went abroad for shopping, so the adaptation of the population to external challenges for the food market was more significant.</p>