The competitiveness of nature-based Health Tourism (NHT) industry, especially in the Alpine regions, is increasingly linked to the sustainability and exploitation of unique natural resources of tourism destinations, which often lack the access to knowledge and networks of stakeholders to improve their offerings. In this sense, the use of digital tools can open up further opportunities to reconsider value offerings and better access different knowledge resources and relationships within the industry network. This Chapter illustrates the collaborative design approach adopted in HEALPS2 for the development of an ontology-based Decision Support System for health tourism destinations. The resulting ontology aims to model the relationships between the available natural resources, the value offerings and the target groups of NHT destinations. Moreover, the Collaborative Design approach foresees the involvement of end-users (i.e. not only tourism destinations, but also the network of stakeholders, and the actual and potential future tourists) as both sources of knowledge and validators of the ontology and its outputs, aiming to inform decision-making processes in a shared knowledge model that leverages on digital tools.