| 2026-10-08 | M. Clark | Gillingham → Hartlepool | Free agent |
| 2026-09-28 | T. Eaves | Northampton → Gillingham | Free agent |
| 2026-09-25 | R. Luthra | Eastbourne Borough → Gillingham | Free agent |
| 2026-09-23 | J. Williams | Gillingham → Eastleigh | Free agent |
| 2026-09-01 | Z. Obiero | Leyton Orient → Gillingham | Loan |
| 2026-08-31 | Z. Obiero | Leyton Orient → Gillingham | Loan |
| 2026-08-31 | E. King | Cardiff → Gillingham | Transfer |
| 2026-08-30 | E. King | Cardiff → Gillingham | Transfer |
| 2026-08-29 | J. Daley | Middlesbrough → Gillingham | Loan |
| 2026-08-27 | A. Rowe | Gillingham → AFC Hornchurch | Free agent |
| 2026-08-26 | L. Sillah | Nottingham Forest → Gillingham | Loan |
| 2026-08-25 | A. Maynard-Brewer | Gillingham → Sheffield Wednesday | Return from loan |
| 2026-08-24 | C. Masterson | Gillingham → Reading | Free agent |
| 2026-08-20 | J. Turner | Gillingham → Newport County | Free agent |
| 2026-08-19 | J. Turner | Gillingham → Newport County | Free agent |
| 2026-08-18 | S. Palmer-Houlden | Gillingham → Motherwell | Transfer |
| 2026-08-17 | S. Palmer-Houlden | Gillingham → Motherwell | Transfer |
| 2026-08-14 | A. Maynard-Brewer | Sheffield Wednesday → Gillingham | Loan |
| 2026-08-08 | O. Mason | Gillingham → Mansfield Town | Return from loan |
| 2026-08-06 | O. Mason | Mansfield Town → Gillingham | Loan |
| 2026-08-05 | N. Khumbeni | Gillingham → Eastleigh | Loan |
| 2026-08-03 | S. Kendall | Millwall → Gillingham | Loan |
| 2026-08-02 | Conor McManus | Brentford → Gillingham | Transfer |
| 2026-08-01 | Conor McManus | Brentford → Gillingham | Transfer |
| 2026-07-30 | S. Gale | Gillingham → Barnsley | Transfer |
| 2026-07-29 | S. Gale | Gillingham → Barnsley | Transfer |
| 2026-07-28 | S. Tabares | Southampton → Gillingham | Free agent |
| 2026-07-24 | S. Ogie | Gillingham → Woking | Free agent |
| 2026-07-23 | S. Ogie | Gillingham → Woking | Free agent |
| 2026-07-16 | R. Hutton | Gillingham → Chesterfield | Free agent |
| 2026-07-15 | R. Hutton | Gillingham → Chesterfield | Free agent |
| 2026-07-02 | Lennon Maclorg | Charlton → Gillingham | Free agent |
| 2026-07-02 | O. Wright | Southampton → Gillingham | Loan |
| 2026-07-01 | Lenni Rae Cirino | Gillingham → Hednesford Town | Free agent |
| 2026-06-30 | E. Nevitt | Gillingham → Oldham | Free agent |
| 2026-06-30 | J. Andrews | Gillingham → Grimsby | Free agent |
| 2026-06-30 | Marcus Wyllie | Gillingham → Aldershot Town | Transfer |
| 2026-06-30 | Lenni Rae Cirino | Gillingham → Hednesford Town | Free agent |
| 2026-06-30 | K. Harris | Salford City → Gillingham | Free agent |
| 2026-06-30 | J. Brophy | Cambridge United → Gillingham | Free agent |
| 2026-06-30 | L. Gordon | Motherwell → Gillingham | Free agent |
| 2026-06-30 | Z. Albarus | Brighton → Gillingham | Free agent |
| 2026-06-30 | W. Goodwin | Oxford United → Gillingham | Free agent |
| 2026-06-29 | T. Eaves | Northampton → Gillingham | Free agent |
| 2026-06-29 | E. Nevitt | Gillingham → Oldham | Free agent |
| 2026-06-29 | Stanley Skipper | Gillingham → Skipper Stanley | Free agent |
| 2026-06-29 | J. Andrews | Gillingham → Grimsby | Free agent |
| 2026-06-29 | A. Rowe | Gillingham → Rowe Aaron | Free agent |
| 2026-06-29 | A. Rowe | Gillingham → AFC Hornchurch | Free agent |
| 2026-06-29 | M. Clark | Gillingham → Clark Max | Free agent |
| 2026-06-29 | Marcus Wyllie | Gillingham → Aldershot Town | Transfer |
| 2026-06-29 | Lennon Maclorg | Charlton → Gillingham | Free agent |
| 2026-06-29 | J. Brophy | Cambridge United → Gillingham | Free agent |
| 2026-06-29 | L. Gordon | Motherwell → Gillingham | Free agent |
| 2026-06-29 | W. Goodwin | Oxford United → Gillingham | Free agent |
| 2026-06-29 | E. Williams | Gillingham → Dover | Free agent |
| 2026-05-30 | E. Nevitt | Cambridge United → Gillingham | Return from loan |
| 2026-05-30 | Marcus Wyllie | Ebbsfleet United → Gillingham | Return from loan |
| 2026-05-30 | Travis Akomeah | Gillingham → Watford | Return from loan |
| 2026-05-30 | L. Dobbs | Ramsgate → Gillingham | Return from loan |
| 2026-05-30 | Kate Holtam | Cray Valley PM → Gillingham | Return from loan |
| 2026-05-30 | J. Smith | Gillingham → Wigan | Return from loan |
| 2026-04-25 | D. Theodore | Hastings United → Gillingham | Return from loan |
| 2026-03-12 | H. Bridle | Gillingham → Chichester City | Loan |
| 2026-02-25 | H. Bridle | Cray Wanderers → Gillingham | Return from loan |
| 2026-02-22 | Marcus Wyllie | Gillingham → Ebbsfleet United | Loan |
| 2026-02-01 | O. Beckles | Leyton Orient → Gillingham | - |
| 2026-01-28 | Ronan Hale | Ross County → Gillingham | Transfer |
| 2026-01-22 | E. Nevitt | Gillingham → Cambridge United | Loan |
| 2026-01-22 | C. Antwi | Newport County → Gillingham | Transfer |
| 2026-01-20 | Kate Holtam | Gillingham → Cray Valley PM | Loan |
| 2026-01-08 | H. Bridle | Gillingham → Cray Wanderers | Loan |
| 2026-01-05 | L. Dobbs | Gillingham → Ramsgate | Loan |
| 2026-01-01 | D. Theodore | Gillingham → Hastings United | Loan |