Abertondo was the first person to complete a two-way non-stop swim of the English Channel, in 1961. His time for the swim was 43 hours 10 minutes. Abertondo was sponsored by the Argentine Government.
Abertondo made one unsuccessful attempt – on Aug 7th 1950 (time 25 hours), giving up one mile from England.
His other successes were; the Aug 22 1950 and Aug 16 1951 Daily Mail races. He was placed 8th and 14th; and the Aug 21 1954 Billy Butlin race. He was placed sixth.
In 1950 he swam 168 miles down the river Plate in 61 hrs. He once swam 291 miles down the Mississippi River in 3 days, 9 hours.