Semifinal
jeudi 13 décembre 2018, 13h06 GMT – 13h06 GMT
| Nom | Équipe | Temps | |
|---|---|---|---|
| 1 |  Katinka Hosszú | Hungary | 57.69″ |
| 2 |  Runa Imai | Japan | + 0.35″ |
| 3 | Alia Atkinson | Jamaica | + 0.51″ |
| 4 | Melanie Margalis | United States | + 0.64″ |
| 5 | Kathleen Baker | United States | + 0.85″ |
| 6 |  Rika Omoto | Japan | + 0.91″ |
| 6 |  Jenna Laukkanen | Finland | + 0.91″ |
| 8 |  Emily Seebohm | Australia | + 0.95″ |
| 9 | Shiwen Ye | China | + 1.25″ |
| 10 | Mariya Kameneva | Russia | + 1.28″ |
| 11 | Lena Kreundl | Austria | + 1.77″ |
| 12 | Ruta Meilutyte | Lithuania | + 2.12″ |
| 13 |  Ilaria Cusinato | Italy | + 2.16″ |
| 14 | Lidón Muñoz | Spain | + 3″ |
| 15 | Chang Yang | China | + 3.17″ |
| 16 | Susann Bjørnsen | Norway | + 3.35″ |