| Senior League - Division 1B |
| 03/09/2021 |
| 19:30 | Lansdowne | 31 | vs | 14 | Terenure College RFC | More |
| Venue : Lansdowne Road Referee : John Flynn |
| 04/09/2021 |
| 15:00 | St Marys College RFC | 46 | vs | 24 | Dublin University | More |
| Venue : Templeville Rd Referee : Colm Roche |
| 11/09/2021 |
| 15:00 | Dublin University | 16 | vs | 22 | Terenure College RFC | More |
| Venue : College Park Referee : Padraic Reidy |
| 15:00 | St Marys College RFC | 15 | vs | 41 | Lansdowne | More |
| Venue : Templeville Rd Referee : Paul Haycock |
| 17/09/2021 |
| 19:30 | Lansdowne | 13 | vs | 7 | Dublin University | More |
| Venue : Lansdowne Road Referee : John Carvill |
| 18/09/2021 |
| 15:00 | Terenure College RFC | 33 | vs | 17 | St Marys College RFC | More |
| Venue : Lakelands Park Referee : Andrew Cole |