This article examines the materialities of the border assemblage in the central Mediterranean Sea and their impact on encounters and solidarities. By exploring the dynamics of maritime border securitisation, the study reveals how the Mediterranean, traditionally seen as a space of encounter, is increasingly depicted as a battleground. The research highlights the tension between practices of solidarity and border securitisation policies, which create friction among personal memories and social practices, public discourse and media narratives, legal devices, administrative measures, and policing practices. Through ethnographic fieldwork in key locations like Pantelleria, Lampedusa, and the Gulf of Gabès, the article uncovers the progressive racialisation of Mediterranean maritime spaces and the erosion of possibilities for spontaneous encounters and solidarities. The findings suggest that the material forms of the border assemblage contribute to the production of the migrant as a disturbing and threatening subject, transforming the Mediterranean from a space of encounter to one of suspicion and collision. This study calls for reconsidering the Mediterranean’s cultural geographies and the potential futures of its histories, challenging the hegemonic narratives that shape public discourse on migration.