400m U23 Men, Heat:1 of 4 ; Official result
| Rank | Lane | ID | Name | PB | Team | Cat | Result | Info | Video |
| 1 | 5 | 88 | IRWIN Shane | Finn Valley A.C. | 49.09 | Q | |||
| 2 | 4 | 155 | PEPPARD Paul | Monaghan Phoenix A.C. | 50.41 | q | |||
| 3 | 3 | 196 | ST. CLARE JOHNSON Chris | Enniscorthy Juvenile A.C. | 51.21 | ||||
| 4 | 6 | 62 | FRIEL Mark | AthleticsNI Unattached | 52.56 |