Roberto Retolaza had a very lengthy rowing career representing Mexico, with one of his earliest international appearances coming at the 1954 Central American and Caribbean Games. Two years later, he had a surprise victory in the junior Royal Canadian Henley regatta when he defeated two-time champion John Pearce in the preliminary round and went on to victory in the finals. Soon thereafter, he placed third in the senior division. He made his Olympic début at the 1960 Rome Games in the coxless pairs, alongside Arcadio Padilla, and was eliminated in the semifinals. Eight years later the duo returned, this time as a member of the coxless fours squad with Jesús Toscano and David Trejo, and placed eighth overall. A year prior, Retolaza and Padilla had been third in that event, alongside the non-Olympians Fernando and Javier Calleja, at the 1967 Pan American Games. By the 1970s Retolaza was competing in masters’-level competitions and coaching at his club, Club España. He did not fully retire until shortly before his 90th birthday.