Semifinal
jeudi 9 août 2018, 19h50 GMT – 19h50 GMT
| Nom | Équipe | Temps | |
|---|---|---|---|
| 1 |  Laviai Nielsen | Great Britain | 51.21″ |
| 2 |  Maria Belibasaki | Greece | + 0.02″ |
| 3 | Justyna Swiety-Ersetic | Poland | + 0.02″ |
| 4 |  Lisanne de Witte | Netherlands | + 0.03″ |
| 5 | Madiea Ghafoor | Netherlands | + 0.08″ |
| 6 |  Iga Baumgart-Witan | Poland | + 0.14″ |
| 7 | Agne Serksniene | Lithuania | + 0.2″ |
| 8 |  Floria Guei | FFA - France Athlétisme | + 0.29″ |
| 9 |  Libania Grenot | Italy | + 0.33″ |
| 10 | Gunta Vaicule | Latvia | + 0.39″ |
| 11 | Polina Miller | Authorised Neutral Athlete | + 0.44″ |
| 12 | Malgorzata Holub-Kowalik | Poland | + 0.53″ |
| 13 | Anyika Onuora | Great Britain | + 0.56″ |
| 14 | Anita Horvat | Slovenia | + 0.68″ |
| 15 | Amy Allcock | Great Britain | + 0.7″ |
| 16 |  Cynthia Bolingo | Belgium | + 0.71″ |
| 17 | Tetiana Melnyk | Ukraine | + 0.99″ |
| 18 | Catia Azevedo | Portugal | + 1.02″ |
| 19 | Maria Benedicta Chigbolu | Italy | + 1.05″ |
| 20 |  Bianca Razor | Romania | + 1.06″ |
| 21 | Camille Laus | Belgium | + 1.19″ |
| 22 |  Laura Bueno | Spain | + 1.25″ |
| 23 | Andrea Miklos | Romania | + 1.28″ |
| 24 | Tamara Salaški | Serbia | + 1.99″ |