 At international level, he represented Uruguay on 30 occasions between 1990 and 1997, scoring 11 goals, and also took part at the 1990 World Cup and the 1995 Copa América, winning the latter tournament.Fonseca, nicknamed "el castor" ("the beaver"), started his football career at Nacional, his local team in Uruguay, in 1988.He played 14 games in two years and scored 3 goals.