The man from the Bellinzona region abused the children at his home, at a local swimming pool and during holidays in Sicily, according to evidence heard by a Lugano court.
The prosecution said there were 912 known sexual abuse cases over three years, with two of the victims daughters of his former partner, the SDA news agency reported.
The cases were “monstrous and despicable”, the court judge said before handing out the maximum sentence for such a crime under Swiss law.
In addition, to the jail term, the convicted man faces further detention for preventive reasons, SDA said.
A prostitute of Colombian origin was sentenced to four years in prison for her role in some of the cases.
The convicted man paid her to be with him on several occasions as he abused one of the daughters of his former partner, SDA said.
He was convicted in 2003 for sexual contact with minors after impregnating a girl under the age of 16, the news agency said.