In the postal sector, the net cost of universal service depends on the content of the service, the postal market characteristics and the country's geographical configuration. These three groups of factors affect both the direct cost of providing the service and the extent of competition on the market. In this paper, we consider countries with different geographical characteristics and we show that the choice of an appropriate mechanism to share the cost of universal service between market participants depends on the country configuration. Thus, for universal service financing, one size does not fit all.