Semifinal 3
jeudi 9 août 2018, 19h50 GMT – 19h50 GMT
| Nom | Équipe | Temps | |
|---|---|---|---|
| 1 |  Justyna Swiety-Ersetic | Poland | 51.23″ |
| 2 | Madiea Ghafoor | Netherlands | + 0.06″ |
| 3 |  Libania Grenot | Italy | + 0.31″ |
| 4 | Gunta Vaicule | Latvia | + 0.37″ |
| 5 | Polina Miller | Authorised Neutral Athlete | + 0.42″ |
| 6 | Amy Allcock | Great Britain | + 0.68″ |
| 7 |  Bianca Razor | Romania | + 1.04″ |
| 8 |  Laura Bueno | Spain | + 1.23″ |