Bieber lived in Atlanta briefly when he first moved to the United States years ago -- after Scooter Braun signed him -- and his most recent trip has stirred up very fond memories.
In addition to Diddy, Bieber's been hanging with southern staples T.I. and Rick Ross -- and we're told he's already asked them about where to buy the nicest real estate in the city.
Added bonus -- Atlanta isn't the paparazzi hive that L.A. is ... and Bieber has been enjoying the extra privacy ... for now. (Of course, paps tend to go where the money is -- and Bieber's a walking bank.)
It also makes sense because we're told Bieber is transitioning into hip hop -- he's Bizzle now.