Nowadays, active cultural participation is a cornerstone of cultural development in society. Cultural participation can be a powerful driver of social inclusion and developing cultural heritage policy as a part of sustainable tourism. The paper investigates the role of a collaborative approach in the form of co-creation in cultural heritage restoration policy of castles and monasteries in the Slovak Republic. In the past, there were 180 castles; currently, 25 of them are well-preserved and approximately 90 are in ruins. According to sources, Slovakia belongs to the countries with the highest number of castles per inhabitant. During the last 20 years, the civil sector engagement has compensated for inadequate historical heritage protection of the state. Seven non-profit organisations represent it united in an interest association, Saving the Castles. In the form of a case study, the paper analyses these organisations’ cultural heritage restoration activities based on the volunteering activity of castles fans. This collaborative approach refers to an interactive process of sharing experiences and ideas and forming a pool of finance and human resources among stakeholders in order to restore the historical heritage. Thanks to these activities, many crumbling ruins should be transformed into attractive and safe tourist attractions and become unique selling points of Slovakia as a tourism destination. The presented case study can inspire similar places on how to help preserving the historical heritage if the state does not pay adequate attention to this issue.