| POS | Rank | Heat | BIB | ATHLETE | COUNTRY | RESULTS | ms* | 
|---|---|---|---|---|---|---|---|
| 1 | 1 | 1 | 1731 | Hima DAS |  IND | 52.10 Q | |
| 2 | 2 | 1 | 1871 | Andrea MIKLÓS |  ROU | 52.48 Q | |
| 3 | 1 | 3 | 1510 | Ella CONNOLLY |  AUS | 52.78 Q SB | |
| 4 | 2 | 3 | 1808 | Mary MORAA |  KEN | 52.98 Q | |
| 5 | 3 | 1 | 1776 | Stacey Ann WILLIAMS |  JAM | 53.00 q | .993 | 
| 6 | 1 | 2 | 1960 | Taylor MANSON |  USA | 53.00 Q | .000 | 
| 7 | 2 | 2 | 1561 | Ashlan Best |  CAN | 53.24 Q PB | .232 | 
| 8 | 4 | 1 | 1758 | Elisabetta VANDI |  ITA | 53.24 q NU20R | .233 | 
| 9 | 3 | 2 | 1600 | Roxana GÓMEZ |  CUB | 53.26 | |
| 10 | 4 | 2 | 1549 | Tiffani MARINHO |  BRA | 53.30 | |
| 11 | 3 | 3 | 1748 | Davicia Patterson |  IRL | 53.57 | |
| 12 | 5 | 1 | 1565 | Sharelle Samuel |  CAN | 53.68 | |
| 13 | 5 | 2 | 1733 | Jisna Mathew |  IND | 53.86 | |
| 14 | 6 | 2 | 1617 | Fiordaliza COFIL |  DOM | 53.94 | |
| 15 | 6 | 1 | 1587 | Yu Zhou |  CHN | 54.00 SB | |
| 16 | 4 | 3 | 1646 | Frehiywot WONDIE |  ETH | 54.14 | |
| 17 | 5 | 3 | 1553 | Giovana dos Santos |  BRA | 54.30 | |
| 18 | 7 | 1 | 1578 | Shalysa WRAY |  CAY | 54.32 | .311 | 
| 19 | 8 | 1 | 1932 | Stella Wonruku |  UGA | 54.32 | .317 | 
| 20 | 6 | 3 | 1718 | Amanda Crawford |  GRN | 54.36 | |
| 21 | 7 | 2 | 1697 | Laura Kaufmann |  GER | 54.91 | |
| 22 | 7 | 3 | 1900 | Veronica VANCARDO |  SUI | 55.13 | |
| 23 | 8 | 3 | 1582 | Nuo Liang |  CHN | 55.51 | |
| 2 | 1597 | Angie Melisa Palacios |  COL | DNS | 
ms - Milliseconds - shown when two or more competitors finish with the same time down to hundredths of a second