National parks (NPs) are the flagships of protected areas, which primarily serve the protection of nature, but are also important sites for tourism. While karst areas are generally disadvantageous in terms of traditional farming, tourism can provide new livelihoods for those who live there. Therefore, it does matter how the local people relate to the NP and tourism, and the opinion of tourists is also an important factor. In this article, we present the results of a questionnaire survey conducted in the Aggtelek National Park (ANP) and the Slovak Karst National Park (SKNP). Our results show that for locals, the forest is the most important natural resource often visited by them, while for tourists, caves are the first choice. Conflicts between locals and tourists are negligible, and all actors agree to further increase tourism. In both ANP and SKNP, the majority of tourists and locals alike have a rather positive view of the NP. However, there is still a significant group of local residents who have a negative opinion about the NP. One reason for this may be that the locals feel they have only a marginal influence on NP decisions. The ANP plays a more important role in the lives of locals than in SKNP, because ANP has a larger organisational background and more human resources for a smaller population. Although geotourism is still largely missing from the vocabulary of local residents and park management alike, there is a small but significant part of visitors who consider themselves sensu lato geotourists. As for the motivation of tourists, the keyword is “cave”, while the content of the term “karst” is much less known for visitors (especially on the Hungarian side). In Hungary, the tourism to Baradla Cave is largely due to school education. We found that the internet, although one of the most important sources of information for visitors, was not the first port of call, and was not outstanding compared to other factors.