| 2. Round | 02/04/2021 | Treaty United | - | Wexford FC | 1:0 |  |
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| 4. Round | 16/04/2021 | Galway United | - | Treaty United | 1:1 | ||||
| 5. Round | 23/04/2021 | Treaty United | - | Cork City | 2:1 |  |
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| 6. Round | 30/04/2021 | Shelbourne FC | - | Treaty United | 2:2 |  |
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| 7. Round | 07/05/2021 | UC Dublin | - | Treaty United | 3:2 | ||||
| 8. Round | 14/05/2021 | Treaty United | - | Athlone Town | 1:0 | ||||
| 9. Round | 21/05/2021 | Cabinteely FC | - | Treaty United | 2:1 | |
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| 12. Round | 19/06/2021 | Cobh Ramblers | - | Treaty United | 0:2 | |
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| 13. Round | 25/06/2021 | Treaty United | - | Galway United | 0:1 | |
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| 14. Round | 02/07/2021 | Cork City | - | Treaty United | 2:3 | ||||
| 16. Round | 16/07/2021 | Treaty United | - | UC Dublin | 2:1 | ||||
| 17. Round | 30/07/2021 | Athlone Town | - | Treaty United | 1:4 | ||||
| 18. Round | 06/08/2021 | Treaty United | - | Cabinteely FC | 1:4 | |
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| 21. Round | 03/09/2021 | Treaty United | - | Cobh Ramblers | 3:0 | ||||
| 22. Round | 10/09/2021 | Galway United | - | Treaty United | 0:0 | ||||
| 23. Round | 24/09/2021 | Treaty United | - | Cork City | 0:0 | ||||
| 24. Round | 01/10/2021 | Shelbourne FC | - | Treaty United | 1:0 | ||||
| 27. Round | 29/10/2021 | Cabinteely FC | - | Treaty United | 0:2 |
Ireland