The study uses meta-analysis to provide insights into the value of international marine resources, illustrating the issue with the case of the Baltic Sea. Willingness to pay for water quality improvements varies systematically with factors such as a country’s income level, characteristics of the change in water quality, water body type, study year and methodology. The results of the meta analysis are applied to benefit transfer in order to assess the distribution of the benefits of marine protection measures between the Baltic Sea countries and to compare the results with previous research. The net benefits of protecting the Baltic are positive, but they are asymmetrically distributed between the littoral countries.