Semifinal
mardi 11 décembre 2018, 13h14 GMT – 13h14 GMT
| Nom | Équipe | Temps | |
|---|---|---|---|
| 1 |  Olivia Smoliga | United States | 56.13″ |
| 2 |  Kathleen Baker | United States | + 0.14″ |
| 3 |  Katinka Hosszú | Hungary | + 0.33″ |
| 4 | Georgia Davies | Great Britain | + 0.36″ |
| 5 |  Emily Seebohm | Australia | + 0.71″ |
| 6 | Minna Atherton | Australia | + 0.92″ |
| 7 |  Simona Kubová | Czech Republic | + 1.05″ |
| 8 | Emi Moronuki | Japan | + 1.19″ |
| 9 | Sayaka Akase | Japan | + 1.35″ |
| 10 |  Michelle Coleman | Sweden | + 1.44″ |
| 11 |  Mathilde Cini | France | + 1.57″ |
| 12 | Yuanhui Fu | China | + 1.7″ |
| 13 |  Mimosa Jallow | Finland | + 1.73″ |
| 14 | Anastasia Fesikova | Russia | + 1.75″ |
| 15 |  Margherita Panziera | Italy | + 2.18″ |
| 16 | Alicja Tchórz | Poland | + 2.27″ |