400m Women Heats, Heat:1 of 3 ; Official result since 13:31
Karen Shinkins 51.58 (2002)
| Rank | Lane | ID | Name | PB | Team | Cat | Result | Info | Video |
| 1 | 6 | 226 | MCMANUS Catherine | 00:24.24 | Dublin City Harriers A.C. | 54.00 | Q | ||
| 2 | 5 | 75 | DENNY Sinead | 00:24.57 | Dundrum South Dublin A.C. | 54.57 | q | ||
| 3 | 4 | 294 | PATTERSON Davicia | 54:50.00 | Beechmount Harriers | 56.30 | |||
| 4 | 2 | 260 | NEVILLE Jessica | 00:25.90 | Leevale A.C. | 59.71 | |||
| 5 | 3 | 187 | LYNAM Caoimhe | Dublin City Harriers A.C. | 1:00.71 |