| 2026-10-23 | Tariq Al-Sadi | Enfield Town → Leyton Orient | Return from loan |
| 2026-10-13 | Noah Phillips | Gateshead → Leyton Orient | Return from loan |
| 2026-10-05 | D. Carter | Leyton Orient → Walton & Hersham | Loan |
| 2026-09-24 | Tariq Al-Sadi | Leyton Orient → Enfield Town | Loan |
| 2026-09-18 | Z. O’Keefe | Welling United → Leyton Orient | Return from loan |
| 2026-09-15 | Noah Phillips | Leyton Orient → Gateshead | Loan |
| 2026-09-09 | M. Craig | Leyton Orient → Harrogate Town | Loan |
| 2026-09-07 | Cristian Păscăluță | Spartanii Selemet → Leyton Orient | Free agent |
| 2026-09-02 | A. Gilbert | Middlesbrough → Leyton Orient | Free agent |
| 2026-09-01 | Z. Obiero | Leyton Orient → Gillingham | Loan |
| 2026-08-31 | Z. Obiero | Leyton Orient → Gillingham | Loan |
| 2026-08-31 | D. Levitt | Leyton Orient → Motherwell | Transfer |
| 2026-08-31 | D. Scarlett | Tottenham → Leyton Orient | Free agent |
| 2026-08-31 | O. Dovin | Coventry → Leyton Orient | Loan |
| 2026-08-30 | D. Levitt | Leyton Orient → Motherwell | Transfer |
| 2026-08-30 | D. Scarlett | Tottenham → Leyton Orient | Free agent |
| 2026-08-27 | A. Mohamud | Leyton Orient → Mohamud Abdi | Free agent |
| 2026-08-23 | T. Bakinson | Leyton Orient → Plymouth | Loan |
| 2026-08-20 | Z. O’Keefe | Leyton Orient → Welling United | Loan |
| 2026-08-10 | A. Gilchrist | West Brom → Leyton Orient | Loan |
| 2026-08-09 | N. Oyekunle | Southampton → Leyton Orient | Loan |
| 2026-08-06 | J. Kabia | Grimsby → Leyton Orient | Transfer |
| 2026-08-05 | J. Kabia | Grimsby → Leyton Orient | Transfer |
| 2026-08-03 | D. Ballard | Leyton Orient → Bristol City | Transfer |
| 2026-08-02 | D. Ballard | Leyton Orient → Bristol City | Transfer |
| 2026-08-01 | Tariq Al-Sadi | Leyton Orient → Leyton Orient | Free agent |
| 2026-07-27 | S. Boniface | Ipswich → Leyton Orient | Loan |
| 2026-07-22 | H. Bullas | Leyton Orient → Bromley | Free agent |
| 2026-07-20 | J. Olowu | Stockport County → Leyton Orient | Transfer |
| 2026-07-19 | J. Olowu | Stockport County → Leyton Orient | Transfer |
| 2026-07-10 | Y. Akhamrich | Tottenham → Leyton Orient | Loan |
| 2026-07-09 | I. Hayden | QPR → Leyton Orient | Free agent |
| 2026-07-08 | J. Koroma | Leyton Orient → Chesterfield | Loan |
| 2026-07-03 | A. Abdulai | Leyton Orient → Hibernian | Transfer |
| 2026-07-02 | A. Abdulai | Leyton Orient → Hibernian | Transfer |
| 2026-07-02 | N. Baxter | Watford → Leyton Orient | Transfer |
| 2026-07-01 | N. Baxter | Watford → Leyton Orient | Transfer |
| 2026-07-01 | J. Simpson | Leyton Orient → Chesterfield | Free agent |
| 2026-06-30 | S. Perkins | Leyton Orient → Wigan | Transfer |
| 2026-06-30 | T. James | Leyton Orient → Bristol Rovers | Free agent |
| 2026-06-30 | Makai Welch | Leyton Orient → AFC Hornchurch | Free agent |
| 2026-06-30 | T. Springett | Norwich → Leyton Orient | Free agent |
| 2026-06-30 | A. Dobra | Chesterfield → Leyton Orient | Transfer |
| 2026-06-30 | F. Stevens | FC St. Pauli → Leyton Orient | Transfer |
| 2026-06-30 | J. Simpson | Leyton Orient → Chesterfield | Free agent |
| 2026-06-30 | D. Happe | Leyton Orient → Aberdeen | Free agent |
| 2026-06-29 | H. Bullas | Leyton Orient → Bullas Hayden | Free agent |
| 2026-06-29 | H. Bullas | Leyton Orient → Bromley | Free agent |
| 2026-06-29 | S. Perkins | Leyton Orient → Wigan | Transfer |
| 2026-06-29 | D. Jaiyesimi | Leyton Orient → Jaiyesimi Diallang | Free agent |
| 2026-06-29 | Makai Welch | Leyton Orient → AFC Hornchurch | Free agent |
| 2026-06-29 | Makai Welch | AFC Hornchurch → Leyton Orient | Return from loan |
| 2026-06-29 | D. Bachmann | Leyton Orient → Watford | Return from loan |
| 2026-06-29 | K. Casey | Leyton Orient → West Ham | Return from loan |
| 2026-06-29 | T. Oluwayemi | Leyton Orient → Oluwayemi Toby | Free agent |
| 2026-06-29 | I. Hayden | QPR → Leyton Orient | Free agent |
| 2026-06-29 | A. Gilbert | Middlesbrough → Leyton Orient | Free agent |
| 2026-06-29 | A. Dobra | Chesterfield → Leyton Orient | Transfer |
| 2026-06-29 | F. Stevens | FC St. Pauli → Leyton Orient | Transfer |
| 2026-05-30 | H. Bullas | Enfield Town → Leyton Orient | Return from loan |
| 2026-05-30 | Z. Obiero | Tranmere → Leyton Orient | Return from loan |
| 2026-05-30 | D. Jaiyesimi | Barnet → Leyton Orient | Return from loan |
| 2026-05-30 | P. Chinedu | Barnet → Leyton Orient | Return from loan |
| 2026-05-30 | Ajay Matthews | Leyton Orient → Millwall | Return from loan |
| 2026-05-30 | W. Dennis | Leyton Orient → Bournemouth | Return from loan |
| 2026-05-30 | F. Fawunmi | Leyton Orient → Stoke City | Return from loan |
| 2026-02-01 | Z. Obiero | Leyton Orient → Tranmere | Loan |
| 2026-02-01 | O. Beckles | Leyton Orient → Gillingham | - |
| 2026-02-01 | T. Oluwayemi | Celtic → Leyton Orient | Transfer |
| 2026-02-01 | J. Morris | Watford → Leyton Orient | - |
| 2026-02-01 | W. Dennis | Bournemouth → Leyton Orient | Loan |
| 2026-02-01 | F. Fawunmi | Stoke City → Leyton Orient | Loan |
| 2026-02-01 | D. Levitt | Hibernian → Leyton Orient | Transfer |
| 2026-01-30 | Z. Hambury | Leyton Orient → Canvey Island | - |
| 2026-01-29 | D. Bachmann | Watford → Leyton Orient | Loan |
| 2026-01-24 | A. Mohamud | Canvey Island → Leyton Orient | Return from loan |
| 2026-01-20 | D. Jaiyesimi | Leyton Orient → Barnet | Loan |
| 2026-01-19 | P. Chinedu | Leyton Orient → Barnet | Loan |
| 2026-01-15 | A. Lloyd | Leyton Orient → QPR | Return from loan |
| 2026-01-15 | Ajay Matthews | Millwall → Leyton Orient | Loan |
| 2026-01-15 | K. Casey | West Ham → Leyton Orient | Loan |
| 2026-01-07 | W. Forrester | Bolton → Leyton Orient | - |
| 2026-01-04 | T. Adaramola | Leyton Orient → Crystal Palace | Return from loan |
| 2026-01-04 | J. White | Leyton Orient → Newcastle | Return from loan |