400m Women Heats, Heat:3 of 3 ; Official result since 13:31
Karen Shinkins 51.58 (2002)
| Rank | Lane | ID | Name | PB | Team | Cat | Result | Info | Video |
| 1 | 5 | 22 | BROMELL Jenna | 02:06.26 | Emerald A.C. | 55.13 | Q | ||
| 2 | 6 | 9 | BECKER Sophie | 00:00.00 | St. Joseph's A.C. | 55.25 | q | ||
| 3 | 4 | 196 | MALONE Niamh | 00:59.40 | Monaghan Phoenix A.C. | 58.43 | |||
| 4 | 2 | 150 | HORGAN Mary | 00:59.79 | Crusaders A.C. | 59.99 | |||
| 5 | 3 | 83 | DOYLE Sarah | 01:02.79 | Tallaght A.C. | 1:03.26 |