This paper explores ethnic, cultural and symbolic boundaries in a micro-region within the Mediterranean area of Istria, which is conceptualised as a multicultural, multi-ethnic and multilingual region. In scholarly writings and everyday speech, it is seen as a border zone where people construct multiple pure and hybrid identities. In this paper, I intend to explore some of the geographic, historical, political, and anthropological discourses that are present in the fieldwork location of Istria and North East Adriatic Sea as well as address the issue of national land and maritime borders and ethnic boundaries. I will focus on the border issues in the periods of political and ideological changes after World War II and after 1991, in the wake of the disintegration of Yugoslavia and the creation of Slovenia and Croatia as new post-socialist states. Particular focus will be on the issue of international arbitrage on the maritime and land border in 2017.