Small-scale fishing constitutes the main source of marine products and a central component of local livelihoods for poor families in coastal areas of Costa Rica. This country has been defining marine reserves, and fishermen are believed to be amongst the most prominent opponents of such policies, given the potential costs that entails the lost access of fishing areas of traditional use. However, it seems that this potential economic impact would depend on the livelihoods diversification, and the spatial definition of closures, among others.