Due to the public good nature of many of mangrove's ecosystem services, markets for them do not exist and there is limited potential to manage them with conventional markets. Moreover, because of the difficulties in estimating the value of these non-marketed services, mangroves are often undervalued in benefit cost analysis of conservation versus commercial land uses causing their degradation and loss. With the goal of supporting the current efforts of the government of Costa Rica to develop a new PES scheme that include these ecosystems, as well as other policy initiatives on wetlands conservation and restoration, we applied a hybrid approach to estimate the value of ecosystem services from mangrove forests in the Gulf of Nicoya. Our method consists of traditional benefit transfer and expert modified benefit transfer for 11 ecosystem services, and the application of more specific methods to estimate three of those ecosystem services (i.e. climate regulation, fisheries and coastal protection). Using traditional benefit transfer, we estimated the total economic value of ecosystem services of mangroves in the Gulf of Nicoya in $812 million per year (median=$88 million/year), and the total mean value of the ecosystem services provided by all the mangroves in Costa Rica as $1.5 billion per year (median=$160 million/year). By applying the expert modified benefit transfer we estimated that the mean total value of the mangrove forests of the Gulf of Nicoya is $470 million per year, and a median value of $75 million per year. Combining the three different valuation technics, we calculated the mean total value of the ecosystem services from mangrove forests in the Gulf of Nicoya in $408 million per year, and a median total value of $86 million. Considering the median total value of ecosystem services from mangroves, it represents 0.16% of the GDP in Costa Rica in 2015.