The present study investigates mortality convergence in the EU’s internal border regions, a perspective that has not been explored before. We examine life expectancy trends in 277 EU border regions from 1995, the year the Schengen Treaty came into force, until 2019, the last year before the onset of the COVID-19 pandemic. We chose 1995 as our starting point, as it marks the implementation of the Schengen Agreement, which brought about a notable shift in cross-border mobility for the founding members of the European Union. This development fostered greater economic, social, and healthcare integration among these countries. During this time, new cohesion policy instruments were also launched, such as the Cohesion Fund [25] and the Interreg programme. While these initiatives aimed primarily at enhancing economic and territorial integration, their potential long-term effects on health convergence have yet to be thoroughly examined, as much of the previous research has concentrated on economic outcomes (e.g., [26, 27]). By extending our study into the late 1990s, we not only capture the initial impacts of these institutional changes but also observe the longer-term trends in life expectancy. In addition, we quantify the relative improvements in life expectancy in border regions by comparing them with several reference groups: (i) neighbouring border regions, (ii) non-border regions within the same country, and (iii) all selected countries combined.