The entry in March 2014 of the Crimean Peninsula into Russia has significantly changed the lives of the population of this territory, and also influenced international relations with the participation of the Russian Federation. However, so far the processes related to the complete transition of the Republic of Crimea and the city of Sevastopol into the domestic legal field have not been completed. In some sectors of the economy, the deadlines for the completion of such “transitional” measures are constantly being extended. At the same time, the religious sphere did not require significant changes. The changes that began in Ukraine after 2014, scandals and harassment against religious organizations, unthinkable in Russia, only strengthen believers in the correctness of their choice. The significance of this study is actualized by the prospect of passing through similar stages of adaptation of regulatory regulation and the practice of its application in the Donetsk and Lugansk People's Republics, Zaporizhia and Kherson regions. The purpose of the work is to compare the normative legal regulation of religious relations in Russia and Ukraine, as well as in the Republic of Crimea and the federal city of Sevastopol in order to formulate a conclusion about the degree of completion of the reintegration of the Crimean Peninsula into Russia. Research objectives: to study the Ukrainian legal regulation of these public relations in order to identify deviations unacceptable by the population of the territory in question; to search for similar norms in Russian legislation; to identify positive foreign experience; to determine the degree of activity of regional authorities in terms of support for confessional and interfaith relations. The main method of research, in addition to general philosophical and general scientific ones, was comparative law. The method of modeling and expert assessments was also used in the formulation of the main author's conclusions. According to the results of the study, it is stated that the reintegration of the Crimean Peninsula into Russia in terms of the legal regulation of religious relations has not begun, but rather continues, strengthened by measures taken by the law-making bodies of the neighboring state.