Russia’s 2014 annexation of Crimea and 2022 invasion of Ukraine has reshaped security in the Baltic Sea Region. Finland and Sweden’s decision to commence NATO-accession processes creates a new border between NATO and Russia and new strategic realities. This research project studies the Baltic Sea islands of Gotland, Bornholm and Åland as sites of militarisation. These islands have historically played a strategic role in regional security, most recently in relation to control over maritime space, access to key sites such as Kaliningrad, grey zone activities and energy security. Militarisation of the Baltic Sea region is expected to increase, heightening this zone as a security concern for Nordic states, NATO and Russia. Representations of the islands as security hotspots may however compete with other meanings, such as the islands’ importance for tourism, business and the sensitive Baltic Sea ecosystem. The project aims to make visible the assumptions that enable the militarization of these Baltic Sea islands. We draw on analytical concepts across two theoretical fields: constructivist international relations approaches to identity and security; and feminist security approaches to protection and militarization. The study explores both state and local (potentially oppositional) discourses of threat and insecurity, drawing on empirical material such as official policy documents, media representations as well as interviews with local stakeholders on the islands.