As defined by the World Tourism Organization, sustainable tourism seeks to balance environmental preservation, respect for local cultures, and economic viability. In protected natural areas, such as the UNESCO-designated Delta del Po Natural Park, this balance requires careful consideration of environmental resources, the cultural identity of hosting communities, and long-term socio-economic benefits. The design of outdoor accommodations in these areas is particularly critical, as it directly influences ecological impacts and visitor experiences. This research addresses the challenge of developing eco-compatible constructions for the Delta del Po Natural Park, by combining site and microclimatic analysis and user-needs. Key principles include the integration of passive bioclimatic strategies, the use of bio-based materials, and the reversibility of structures. A pilot project was analysed and optimisation strategies were proposed to enhance environmental performance. Interventions included improving the building envelope implementing passive strategies, and material substitution with bio-based options. Preliminary findings show potential reductions in environmental impact highlighting the role of bio-based materials and eco-compatible technologies in achieving sustainable construction in biodiverse areas.