Brian Wylie, of Clayton Road, Clayton, appeared via video link at Bradford Crown Court to be sentenced for a total of five charges, including indecent assault and gross indecency of a child under the age of 14, and sexual assault of a child under the age of 13.
Wylie was sentenced to 12 years imprisonment in total with a three-year extended licence period.
He was also made subject to a sexual harm prevention order until further notice and must register as a sex offender indefinitely.
Prosecutor David McGonigal outlined how the 64-year-old had admitted three historic offences.
One victim was so young they didn’t know what he was asking them to do was wrong, the prosecutor told the court.
He had faced a trial on further charges, and had been found guilty in March of two counts of sexual assault of a child.
His three victims were said to have suffered long-lasting trauma as a result of the attacks, including incidents of self-harm and struggling with an eating disorder.