Numerous policy instruments have been proposed to promote the provision of ecosystem services (ES) by agro-ecosystems. However, the design of sound incentive schemes is still a challenge, partly because of the difficulty to adapt it to the particularities of agro-ecosystem and socio-economic conditions. To respond to this challenge, we developed and tested a new approach to explore the possible effects of policy instruments on farmers' adoption of practices leading to enhance the ES provision in coffee agroforestry systems. We applied this approach in two watersheds in Centro America, where coffee plantations provide both ES and disservices. First, we conducted semistructured interviews to coffee producers to analyze the diversity of their production systems and current responses to existing policies. Second, we developed a specific role-playing game (RPG) to simulate the effects of three instruments: the enforcement of the current regulatory environmental law, the setting of a specific Payment for Environmental Services; the development of green credits and environmental certification of products. We found that existing instruments are currently not effective in the regions but farmers would be responsive to some of the new incentives. Simulations showed that positive incentives would be the most effective to reduce environmental impacts without decreasing coffee production while an increased enforcement of the law impacts would negatively affect coffee production. After discussing the feasibility of the implementation of these incentives and the interests and limits of RPG method, we argue that it facilitates the co-design of sound incentives to overcome the challenges of multiple ES provision in agro-ecosystems. (Texte intégral)