400m U18 Men, Heat:1 of 3 ; Official result since 10:42
49.59 John Fitzsimons
| Rank | Lane | ID | Name | PB | Team | Cat | Result | Info | Video |
| 1 | 4 | 330 | RAFTERY Jack | Donore Harriers | 52.75 | Q | |||
| 2 | 3 | 335 | CARTHY Ciaran | Dundrum South Dublin A.C. | 52.76 | q | |||
| 3 | 5 | 946 | MCLOUGHLIN Tom | Derry Track Club | 54.56 | ||||
| 4 | 6 | 337 | KELLY Luke | Brothers Pearse A.C. | 59.00 | ||||
| 5 | 2 | 329 | BRADSHAW Aaron | North Leitrim A.C. | 1:01.39 |