400m U18 Men, Heat:2 of 2 ; Official result since 12:04
CBP 49.70 Christopher O'Donnell
| Rank | Lane | ID | Name | PB | Team | Cat | Result | Info | Video |
| 1 | 4 | 714 | MITCHELL Jack | St. L. O'Toole A.C. | 51.18 | Q | |||
| 2 | 3 | 567 | DUFFY Christopher | Tallaght A.C. | 51.21 | Q | |||
| 3 | 5 | 393 | ODUBOTE Tony | Ennis Track A.C. | 51.37 | Q | |||
| 4 | 2 | 715 | HAYDEN Jack | Menapians A.C. | 52.44 | q | |||
| 5 | 6 | 144 | BRESLIN Conor | Finn Valley A.C. | 53.08 | q | |||
| 6 | 7 | 138 | KENNY Eoin | Waterford A.C. | 53.18 | ||||
| 7 | 1 | 216 | HORKAN Dylan | Longford A.C. | 58.39 |