Abstract: Social media is arguably the most widespread tool for digital communication in Europe and worldwide, which makes it particularly important to investigate how this type of communication tool affects and reflects the processes that shape the urban physical and socio-cultural environment. Its influence on urban realities may be twofold: On one side we can use it as a reflection (or extension) of the processes that occur on the ground; on the other side, the specific ways in which social media operate might influence processes that shape the urban environment. This interaction between the urban and digital spaces is increasingly influencing how collective memory and related heritage discourses are shaped, transformed, and contested. In this article, we present the case of Koper (Italian: Capodistria), the main seaside harbour town of Slovenia, which faced a deep demographic and socio-cultural transformation in the aftermath of the Second World War. Its historic urban core became a deeply contested urban environment, where a hegemonic historical narrative clashed with several subaltern ones. The dissonance between contested narratives has re-emerged in the digital space through a handful of history-oriented Facebook groups in recent years. We analyse how digital tools have influenced the dynamics between the contested narratives and how these refer to specific locations within the town or to its historic urban core as a whole.