Heat 4
dimanche 21 juillet 2019, 03h45 GMT – 03h45 GMT
| Nom | Équipe | Temps | |
|---|---|---|---|
| 1 |  Emma McKeon | Australia | 56.9″ |
| 2 |  Louise Hansson | Sweden | + 0.6″ |
| 3 |  Yufei Zhang | China | + 1.12″ |
| 4 |  Rebecca Smith | Canada | + 1.3″ |
| 5 |  Farida Osman | Egypt | + 1.53″ |
| 6 |  Erin Gallagher | South Africa | + 2.31″ |
| 7 | Alys Thomas | Great Britain | + 2.35″ |
| 8 |  Emilie Beckmann | Denmark | + 3.04″ |
| 9 | Ana Monteiro | Portugal | + 3.47″ |
| 10 | Jingwen Quah | Singapore | + 4.59″ |