Flavio Bomio, 71, was found guilty by a court in Lugano of abusing at least 15 boys over a 10-year period.
“Flavio Bomio acted with pre-meditation,” the court’s judge, Marco Villa, said.
The former president of Bellinzona swimming club was also the head coach of the Swiss national team during the 2000 Olympic Games.
Judge Villa added that Bomio used his authority and reputation to abuse the boys.
In 2011 Bomio was revealed as an abuser by two of his victims, and subsequently arrested. His victims were all under 16 and around 400 acts of abuse were recorded between 1997 and 2007.
Bomio admitted the encounters but claimed he was “a victim of nature”. He denied using violence or threats against the children.