Heats
dimanche 12 août 2018, 03h00 GMT – 03h00 GMT
| Nom | Équipe | Temps | |
|---|---|---|---|
| 1 |  Lilly King | United States | 2′ 22.41″ |
| 2 |  Micah Sumrall | United States | + 0.21″ |
| 3 | Satomi Suzuki | Japan | + 1.16″ |
| 4 | Bethany Galat | United States | + 1.37″ |
| 5 | Kelsey Wog | Canada | + 2.72″ |
| 6 |  Sydney Pickrem | Canada | + 3.07″ |
| 7 |  Reona Aoki | Japan | + 3.37″ |
| 8 | Kierra Smith | Canada | + 3.6″ |
| 9 | Julia Sebastian | Argentina | + 4.32″ |
| 10 |  Jessica Hansen | Australia | + 4.69″ |
| 11 | Sakiko Shimizu | Japan | + 4.76″ |
| 12 | Melanie Margalis | United States | + 5.58″ |
| 13 | Macarena Ceballos | Argentina | + 6″ |
| 14 | Muyan Zheng | China | + 9.72″ |
| 15 | Rachel Nicol | Canada | + 11.6″ |
| 16 | Leiston Pickett | Australia | + 12.66″ |