Amid ongoing globalisation, large cities are becoming increasingly attractive to migrants, resulting in a more multiethnic population composition, which underscores the growing importance of studying interethnic relations in metropolises. This work aims to explore the spatial localisation of ten ethnic groups residing in St. Petersburg: Ukrainians, Belarusians, Tatars, Jews, Georgians, Armenians, Azerbaijanis, Uzbeks, Tajiks and Moldovans. Using the ethnic concentration coefficient, the study examines the territorial heterogeneity of settlement among the city’s largest ethnic diasporas to identify patterns in residential choice. The data on national composition are derived from all-Russian population censuses. Most national minorities are distributed rather evenly across the city, but the Jewish and Georgian communities are notably concentrated in the central district of St. Petersburg. At the same time, the migration restrictions imposed due to the COVID-19 pandemic not only decreased the size of the Uzbek and Tajik diasporas, thereby normalising their gender and age distribution but also led to a more even dispersion of these ethnic groups across the city. Currently, there is no evident correlation between the spatial concentration of most ethnic groups in St. Petersburg and their level of social well-being. © Zhitin, D. V. 2024. All rights reserved.