The Mediterranean’s historic urban centres are often facing rising challenges due to overtourism, threatening both cultural heritage and local urban balance. This paper investigates the interplay between spatial configuration and tourist mobility in the historic Medina of Sousse, a UNESCO World Heritage Site facing rising tourism pressure. Despite the growing body of research on over tourism and heritage management, there remains a lack of spatially grounded analytical tools that diagnose tourist flow imbalances within historic urban fabrics. By combining Space Syntax and GIS-based spatial analysis, the study develops a diagnostic framework to assess connectivity, accessibility, and spatial vulnerability. The methodology identifies patterns of tourist concentration in highly integrated areas and highlights underutilized peripheral zones. These imbalances pose threats to both heritage conservation and social equity. The results support a spatial zoning strategy that redirects flows through alternative routes, promoting a more balanced and sustainable tourism model. The study provides practical insights for urban planners and heritage managers seeking to harmonize tourist experience with the protection of historic urban landscapes.