Iglesias, known by his nickname Dorado, was the World Professional Marathon Swimming Federation world champion in 1967, 1969, 1971 and 1972. He was runner-up in 1968 and 1970. He won the 24 Heures La Tuque relay swim six times with three different partners, including Egypt’s Abou Heif and Holland’s Judith DeNys. He also won the 34K (21-mile) Traversée internationale du Lac St-Jean professional race in Canada in 8 hours and 55 minutes in 1967, in 9 hours and 31 minutes in 1968, in 9 hours and 32 minutes in 1969, in 8 hours and 39 minutes in 1971 with a second in 1970, and excelled in the warm-water professional swims in South America. He won the 37K (23-mile) la Descente ou remontée du Saguenay in 6 hours and 3 minutes in 1967 and was fifth in 9 hours and 22 minutes in 1968.