RAJAR figures show an average audience of 6.69 million in the three months to December and an increase of almost a quarter of a million 15-24-year-olds.
Radio 1's overall reach of 11 million was maintained, with 42% of young people in the UK listening to the station.
Around 3.43 million 15-24-year-olds now tune in to the network, compared with 3.27 million in the last quarter. The average age of listeners has therefore dropped from 33 to 32.
Meanwhile, 1Xtra continues to reach over a million listeners a week, with new drivetime host Charlie Sloth achieving a 12% audience increase to 328,000.
Ben Cooper, controller of BBC Radio 1 & 1Xtra said: "What a fantastic quarter for Radio 1. I'm delighted with the figures and they have exceeded my expectation for a brand new Breakfast Show.
"This has been the biggest schedule change in a generation which has resulted in the station's audience getting younger.
"1Xtra also saw big changes this quarter from a brand new drivetime show with Charlie Sloth and I'm delighted that this million-strong network has found a new star."
In an exclusive interview with Digital Spy, BBC Radio 1's head of music George Ergatoudis recently brushed off suggestions that the station has complete control over the UK music charts.
Watch Nick Grimshaw chat to DS below: