Heat 4
vendredi 14 décembre 2018, 03h13 GMT – 03h13 GMT
| Nom | Équipe | Temps | |
|---|---|---|---|
| 1 |  Ariarne Titmus | Australia | 3′ 58.58″ |
| 2 |  Leah Smith | United States | + 1.88″ |
| 3 | Erica Musso | Italy | + 4.79″ |
| 4 | Valeria Salamatina | Russia | + 5.93″ |
| 5 | Carla Buchanan | Australia | + 6.42″ |
| 6 | Diana Durães | Portugal | + 7.07″ |
| 7 |  Haley Anderson | United States | + 7.31″ |
| 8 | Katja Fain | Slovenia | + 7.47″ |
| 9 | Mayuko Gotou | Japan | + 8.23″ |
 Boglárka Kapás | Hungary | DNS |