Kristofer Johnstone, 33, was jailed for 10 years at the High Court in Glasgow today.
He previously denied the charges but was convicted after a trial last month.
Johnstone preyed on the first victim in Glasgow’s Knightswood and on the Isle of Bute.
The second youngster was attacked in the city’s Maryhill and Paisley, Renfrewshire.
The crimes spanned between 2003 and 2018.
READ NEXT: Sex attacker jailed for raping two young girls
After the sentencing, Detective Inspector Jan MacColl said: “Johnstone abused the trust of these two children, and I would commend the victims for coming forward and reporting his behaviour to us.
“Investigating events that have happened in the past can present challenges and it can sometimes only be with hindsight that people recognise that what happened to them was abuse.
“Police Scotland has highly trained, specialist officers, across the country who can investigate such offences and, working with partners, ensure perpetrators are brought to justice.
“We are committed to investigating all reports regardless of when abuse happened, where it took place or who was involved. We will listen, we will investigate, and we will take prompt action to ensure that no one else is at risk of harm. We would ask anyone wishing to report abuse to contact us on 101.”
