<p>Although one of the goals of geoparks is to protect geological heritage and to strive for sustainable development of the surrounding communities, many popular sites are experiencing overtourism that undermines these efforts. Negative impacts of intensive tourism typically include environmental degradation, loss of biodiversity, congestion of transport and tourism infrastructure, negative visitor experience, social conflict, and cultural erosion in local communities. It is, therefore, advisable to prevent overtourism and focus not only on its measurable manifestations (objective dimension) but also on its perception by residents and visitors (subjective dimension). In this paper, we present a method for identifying overtourism-affected sites in the Bohemian Paradise UNESCO Global Geopark, using a web-based participatory mapping application. The results showed that the method, even with a relatively small sample of respondents, gives good and very specific results, allowing subsequent consideration of the findings in tourism management plans of geoparks. Although participatory mapping is not one of the usual data collection methods in tourism, its use can be recommended since it is not only nature that suffers from over-tourism but also residents who will be happy to participate in solving this problem.</p>