But Addicks manager Chris Powell has told four more - Stephen Camacho, Joe Carter, Brandon Hall and Connor Morris - they will all leave the club when their scholarships end the summer.
Powell said: "That was my first experience of either signing young players or not signing them.
"We've signed three - goalkeeper Conor Gough, midfielder Freddie Warren and striker Tosan Popo - but sadly we've had to let four players go.
"It happens year in, year out, but I'm looking for those players to come back in the future. They shouldn't let go of their dream of becoming a professional footballer, it's just maybe not their time at present.
"We're pleased with the lads who have signed. We'll give them a chance to grow and become young men. But there's always a tinge of sadness that the future of other players lies elsewhere."
Source: PA
Source: PA