Under way since 2012, the operation has resulted in the arrest of 29 people, 11 of them from the group in the Philippines that facilitated the abuse, Britain's National Crime Agency (NCA) said in a statement Wednesday.
Some of the people who arranged for the abuse, which was filmed on webcams, were from the children's own families, it said.
Fifteen children between the ages of 6 and 15 have been rescued in the Philippines, the British agency said.
The investigation was a joint effort between the NCA, the Australian Federal Police and U.S. Immigration and Customs Enforcement.
The operation began after British police found "indecent videos" on computers at the home of a registered sex offender.
The ensuing investigation eventually uncovered the abuse being carried out in the Philippines and people in other countries who were involved in the pedophile ring, the NCA said.
Seventeen arrests were made in Britain, the agency said, resulting in five convictions.
"This investigation has identified some extremely dangerous child sexual offenders who believed paying for children to be abused to order was something they could get away with," said Andy Baker, deputy director of the NCA's Child Exploitation and Online Protection command.