400m U23 Men, Heat:1 of 3 ; Official result since 12:48
| Rank | Lane | ID | Name | PB | Team | Cat | Result | Info | Video |
| 1 | 4 | 256 | IRWIN Zak | Sligo A.C. | 49.60 | Q | |||
| 2 | 5 | 297 | BUGGY Eoghan | St Abbans A.C | 50.09 | q | |||
| 3 | 2 | 226 | QUILLIGAN Michael | Nenagh Olympic A.C. | 51.29 | ||||
| 4 | 6 | 362 | MCELGUNN Cathal | Carrick-on-Shannon A.C. | 52.77 | ||||
| 5 | 3 | 139 | SHANLEY Eoghan | Lucan Harriers A.C. | 57.45 |