| Date | 13 – 16 October 2018 | |
|---|---|---|
| Status | YOG | |
| Location | Athletics Field, Parque Olímpico de la Juventud, Villa Soldati, Buenos Aires | |
| Participants | 22 from 22 countries | |
| Format | Two stages with final results determined by cumulative time. | |
| Pos | Competitor | NOC | Time | |||
|---|---|---|---|---|---|---|
| 1 | Guðbjörg Bjarnadóttir |  ISL | 47.02 | Gold | ||
| 2 | Dalia Kaddari |  ITA | 47.69 | Silver | ||
| 3 | Letícia Lima |  BRA | 47.87 | Bronze | ||
| 4 | Barbora Šplechtnová |  CZE | 48.12 | |||
| 5 | Gémima Joseph |  FRA | 48.33 | |||
| 6 | Pia Skrzyszowska |  POL | 48.46 | |||
| 7 | Angie González |  COL | 48.70 | |||
| 8 | Kenisha Phillips |  GUY | 49.01 | |||
| 9 | Shalinda Jansen |  SRI | 49.07 | |||
| 10 | Esperança Cladera |  ESP | 49.16 | |||
| 11 | Princess Roberts |  CAN | 49.29 | |||
| 12 | Chang Li-Ling |  TPE | 49.74 | |||
| 13 | Ivana Ilić |  SRB | 49.78 | |||
| 14 | Viktória Forster |  SVK | 49.84 | |||
| 15 | Ann Kivikas |  EST | 49.96 | |||
| 16 | Akouvi Koumedzina |  TOG | 50.56 | |||
| 17 | Eva Kadyrova |  KGZ | 51.70 | |||
| 18 | Tia George |  DMA | 52.11 | |||
| 19 | Judelande Altidor |  HAI | 52.13 | |||
| 20 | Josée Dedewanou Houeto |  BEN | 54.30 | |||
| 21 | Lujahla Amatya |  NEP | 55.15 | |||
| 22 | Tessy Bristol |  SEY | 55.65 |
