| | Event type
4 × 100 metres Medley Relay, Girls
| Date | 8 October 2018 — 19:29 | |
|---|---|---|
| Status | YOG | |
| Location | Natatorium, Parque Olímpico de la Juventud, Villa Soldati, Buenos Aires | |
| Participants | 28 from 7 countries | |
| Format | Final round only. | |
| Pos | Competitors | NOC | Time | ||||||
|---|---|---|---|---|---|---|---|---|---|
| 1 | People's Republic of China |  CHN | 4:05.18 | Gold | |||||
| Peng Xuwei • Zheng Muyan • Lin Xintong • Yang Junxuan | |||||||||
| 2 | Australia |  AUS | 4:05.46 | Silver | |||||
| Kaylee McKeown • Chelsea Hodges • Michaela Ryan • Abbey Webb | |||||||||
| 3 | Russian Federation |  RUS | 4:06.07 | Bronze | |||||
| Darya Vaskina • Anastasiya Makarova • Polina Yegorova • Yelizaveta Klevanovich | |||||||||
| 4 | Brazil |  BRA | 4:10.93 | ||||||
| Fernanda de Goeij • Ana Vieira • Maria Pessanha • Rafaela Raurich | |||||||||
| 5 | United States |  USA | 4:16.79 | ||||||
| Rhyan White • Kate Douglass • Kaitlynn Sims • Maddie Donohoe | |||||||||
| 6 | South Africa |  RSA | 4:17.78 | ||||||
| Mariella Venter • Christin Mundell • Duné Coetzee • Kate Beavon | |||||||||
| Canada |  CAN | – | |||||||
| Madison Broad • Nina Kucheran • Avery Wiseman • Kyla Leibel | |||||||||