| 04 Sept 24 | S. Edozie Samuel Edozie |  SouthamptonSOU | → |  AnderlechtAND | Loan |
| 30 Aug 24 | R. Macleod Rory Macleod |  Dundee UnitedDUN | → | SouthamptonSOU | Loan |
| 30 Aug 24 | N. Buck Noel Buck |  New England RevolutionNE | → | SouthamptonSOU | Loan |
| 30 Aug 24 | R. Fraser Ryan Fraser |  Newcastle UnitedNEW | → | SouthamptonSOU | Free |
| 30 Aug 24 | J. Meghoma Jayden Meghoma | SouthamptonSOU | → |  BrentfordBRE | Undisclosed |
| 30 Aug 24 | A. Ramsdale Aaron Ramsdale |  ArsenalARS | → | SouthamptonSOU | Undisclosed |
| 30 Aug 24 | M. Cornet Maxwel Cornet |  West Ham UnitedWHU | → | SouthamptonSOU | Loan |
| 28 Aug 24 | C. Alcaraz Carlos Alcaraz | SouthamptonSOU | → |  FlamengoFLA | Undisclosed |
| 27 Aug 24 | S. Charles Shea Charles | SouthamptonSOU | → |  Sheffield WednesdaySHW | Loan |
| 22 Aug 24 | M. Lis Mateusz Lis | SouthamptonSOU | → |  GoztepeGOZ | Undisclosed |
| 21 Aug 24 | S. Mara Sékou Mara | SouthamptonSOU | → |  StrasbourgSTR | Undisclosed |
| 20 Aug 24 | M. Fernandes Mateus Fernandes |  Sporting CPSCP | → | SouthamptonSOU | Undisclosed |
| 16 Aug 24 | L. Ugochukwu Lesley Ugochukwu |  ChelseaCHE | → | SouthamptonSOU | Loan |
| 16 Aug 24 | Juan | SouthamptonSOU | → | GoztepeGOZ | Loan |
| 16 Aug 24 | Juan |  São PauloSAO | → | SouthamptonSOU | Undisclosed |
| 14 Aug 24 | D. Edwards Diamond Edwards | SouthamptonSOU | → |  Port ValePTV | Undisclosed |
| 13 Aug 24 | D. Ballard Dominic Ballard | SouthamptonSOU | → |  BlackpoolBLP | Loan |
| 02 Aug 24 | N. Lawrence Nico Lawrence | SouthamptonSOU | → |  Milton Keynes DonsMKD | Loan |
| 31 Jul 24 | C. Bragg Cameron Bragg | SouthamptonSOU | → |  Crawley TownCRA | Loan |
| 30 Jul 24 | K. Matsuki Kuryu Matsuki |  FC TokyoFCT | → | SouthamptonSOU | Undisclosed |
| 30 Jul 24 | B. Brereton Díaz Ben Brereton Díaz |  VillarrealVIL | → | SouthamptonSOU | Undisclosed |
| 30 Jul 24 | K. Matsuki Kuryu Matsuki | SouthamptonSOU | → | GoztepeGOZ | Loan |
| 23 Jul 24 | C. Adams Ché Adams | SouthamptonSOU | → |  TorinoTOR | Free |
| 19 Jul 24 | L. Payne Lewis Payne | SouthamptonSOU | → |  Cheltenham TownCHL | Loan |
| 16 Jul 24 | F. Downes Flynn Downes | West Ham UnitedWHU | → | SouthamptonSOU | Undisclosed |
| 14 Jul 24 | Y. Sugawara Yukinari Sugawara |  AZ AlkmaarAZ | → | SouthamptonSOU | Undisclosed |
| 12 Jul 24 | Lyanco | SouthamptonSOU | → |  Atlético-MGCAM | Undisclosed |
| 08 Jul 24 | D. Caleta-Car Duje Caleta-Car | SouthamptonSOU | → |  LyonLYON | 3590000 |
| 05 Jul 24 | N. Wood Nathan Wood |  Swansea CitySWA | → | SouthamptonSOU | Undisclosed |
| 04 Jul 24 | Z. Awe Zach Awe | SouthamptonSOU | → |  Accrington StanleyACC | Loan |
| 03 Jul 24 | R. Edwards Ronnie Edwards |  Peterborough UnitedPET | → | SouthamptonSOU | Undisclosed |
| 01 Jul 24 | A. Lallana Adam Lallana | SouthamptonSOU | → | SouthamptonSOU | Free |
| 01 Jul 24 | R. Perraud Romain Perraud | SouthamptonSOU | → |  Real BetisBET | Undisclosed |
| 01 Jul 24 | T. Harwood-Bellis Taylor Harwood-Bellis |  Manchester CityMNC | → | SouthamptonSOU | Undisclosed |
| 01 Jul 24 | C. Taylor Charlie Taylor |  BurnleyBUR | → | SouthamptonSOU | Undisclosed |
| 31 Jan 24 | C. Alcaraz Carlos Alcaraz | SouthamptonSOU | → |  JuventusJUV | Loan |
| 30 Jan 24 | D. Brooks David Brooks |  AFC BournemouthBOU | → | SouthamptonSOU | Loan |
| 26 Jan 24 | K. Doyle Kamari Doyle | SouthamptonSOU | → |  Brighton & Hove AlbionBHA | Undisclosed |
| 15 Jan 24 | J. Rothwell Joe Rothwell | AFC BournemouthBOU | → | SouthamptonSOU | Loan |