This project examines how migrants experience post-2022 securitized membership policies in the Baltic Sea region. National membership includes who should be awarded citizenship, residency or be included in the national community. Current dramatic changes in the Baltic Sea region’s security landscape, has rendered membership increasingly “securitized”, i.e., perceived as a security issue rather than as part of regular politics. The study combines theories about membership and security and launches a new concept, ambivalent securitization, describing a situation where a migrant, on the one hand, is seen as deserving of membership for economic, humanitarian or other reasons, but, on the other hand, is also regarded as a potential threat. This may be due to being a Russian-speaker, a citizen of Russia or a Muslim-majority country, or a migrant with other individual attributes subject to securitizing discourses. Through interviews and policy analysis the study compares experiences of ambivalently securitized migrants across Estonia, Finland and Sweden. Interviewees are recruited within three broad entry-categories subject to the post-2022 membership conditions: (1) refugees, (2) work and student migrants, (3) family migrants. The project will produce unique and societally relevant insights about implications of the securitized membership policies in the Baltic Sea Region.