Marine fisheries in Costa Rica have become characterized by overexploitation, ineffective centralized management and increased conflict among fishing sectors. Despite high economic and socio-cultural importance of small-scale fisheries, no formal mechanisms existed until recently to facilitate the participation of fishers in management. Marine Areas for Responsible Fishing ( Áreas Marinas para la Pesca Responsable , AMPR) were legally recognized in 2009 as a co-management approach, enabling the designation of spatial management areas to be implemented collaboratively by artisanal fishers and government agencies. In this paper, we examine property and access relations shaping this emerging participatory management model using case studies primarily from the Gulf of Nicoya region. The policy demonstrably improves upon some aspects of management, for instance, by allowing artisanal fishers to determine gear restrictions within designated areas. However, the model lacks other attributes of more successful co-management scenarios, particularly exclusive access. The fugitive nature of resources further complicates property relations over these fisheries. The cases explored also illustrate broader institutional and systemic issues that preclude effective participatory management. Lessons from the region are used to propose significant shifts to the management of small-scale fisheries in Costa Rica. [ABSTRACT FROM AUTHOR]