Multi -actor labs (MALs), a form of real -world social experiments, were implemented in three coastal -rural regions in France (Charente River Basin), Spain (Mar Menor), and Greece (South-West Messinia) to better assess and tackle coastal -rural interactions that govern local sustainability challenges, such as water use conflicts and biodiversity degradation. The MALs used participative methodologies based on systems thinking and transition management. Stakeholders were continuously engaged in a series of workshops to co -produce knowledge, reach a common understanding of the sustainability challenges and issues at stake, and co -design solutions in the form of a roadmap for sustainable transitions in coastal -rural regions. This paper evaluates MALs to provide examples of successful sustainability transition experiments based on the outputs produced, outcomes achieved, and processes used in the three coastal, rural regions.