Despite generalised global recommendations, local communities are rarely involved in defining strategic tourism development options. Similarly, methodologies to facilitate these processes of co-creation have not been adequately implemented, tested, and generalised. This study aims to contribute to this body of knowledge by assessing the potential of a participatory planning method centred on the strategic diversification of tourism products. Focusing on the Swedish island of Gotland, where tourism dynamics partly depend on the visits to the Hanseatic town of Visby by cruise ships, a workshop based on an Open Space Methodology (OSM) was implemented, involving local entrepreneurs, representatives of organisations, students, and international researchers in tourism (an original contribution). The results revealed that these “coopetition” processes can contribute to identifying problems and determining possible solutions. In our case, these options can be framed within the concept of “penetration” (modifications and increasing promotion of existing products to the existing markets) involving aspects related to physical and digital infrastructures, along with partnerships and collaborations amongst stakeholders. Overall, this study reveals that the interaction between members and non-members of the local community appears crucial for the emergence of innovative ideas.