The 20 year old Northern Ireland star arrives at Loftus Road from his new employers, having completed a £3million transfer from Sheffield Wednesday.
Charles, who came through City's academy before joining Sheffield Wednesday in 2021, has signed a five-year contract at City to leave the Owls.
The Premier League runners-up will pay the League One outfit an initial £3m with further add-ons linked to first team appearances at the Etihad Stadium.
But he will spend the season in the second tier, after establishing himself as his country's first-choice goalkeeper at Wednesday last campaign.
Pierce Charles is R's for 26/27 💚
— QPR FC (@QPR) July 10, 2026
Despite Wednesday's relegation to League One following an 18-point deduction, his performances attracted significant interest in England.
Speaking after completing the move, Charles said: "To be back at Manchester City is a very special and proud moment both for me and my family.
"I know what a special club City is and I am so excited about looking to the future. City take the development of young players very seriously.
"I know my loan to QPR will only help me grow and improve as a player too. I'll give everything I can for a successful season in the Championship."
The move comes as older brother Shea continues to attract Premier League interest, with Saints rejecting two transfer bids from Leeds United.