2018 IAAF World U20 Championships – Women's 800 metres
The women's 800 metres at the 2018 IAAF World U20 Championships was held at Ratina Stadium on 10, 11 and 12 July.Records
Results
Heats
Qualification: First 4 of each heat and the 4 fastest times qualified for the semifinals.
| Rank | Heat | Name | Nationality | Time | Note |
| 1 | 3 | Ayaka Kawata | JPN | 2:05.08 | Q |
| 2 | 1 | Ayano Shiomi | JPN | 2:05.13 | Q |
| 3 | 5 | Diribe Welteji | ETH | 2:05.18 | Q |
| 4 | 1 | Jackline Wambui | KEN | 2:05.27 | Q |
| 5 | 3 | Lydia Jeruto Lagat | KEN | 2:05.63 | Q |
| 6 | 3 | Maeliss Trapeau | FRA | 2:05.72 | Q |
| 7 | 1 | Samantha Watson | USA | 2:06.34 | Q |
| 8 | 3 | Camille Muls | BEL | 2:06.41 | Q |
| 9 | 1 | Jemima Russell | AUS | 2:06.84 | Q |
| 10 | 5 | Katy-Ann McDonald | GBR | 2:07.24 | Q |
| 11 | 5 | Eloisa Coiro | ITA | 2:07.31 | Q |
| 12 | 5 | Delia Sclabas | SUI | 2:07.43 | Q |
| 13 | 5 | Shaquena Foote | JAM | 2:07.75 | q |
| 14 | 5 | Marharyta Kachanava | BLR | 2:07.87 | q |
| 15 | 2 | Freweyni Hailu | ETH | 2:08.26 | Q |
| 16 | 2 | Carley Thomas | AUS | 2:08.57 | Q |
| 17 | 2 | Gabriela Gajanová | SVK | 2:08.89 | Q |
| 18 | 3 | Federica Cortesi | ITA | 2:09.27 | q |
| 19 | 5 | Jo Keane | IRL | 2:09.59 | q |
| 20 | 1 | Jinlian Tan | CHN | 2:09.81 | |
| 21 | 1 | Mia Helene Mørck | DEN | 2:09.82 | |
| 22 | 2 | Chrissani May | JAM | 2:09.88 | Q |
| 23 | 3 | Liza Kellerman | RSA | 2:10.05 | |
| 24 | 1 | Klara Lukan | SLO | 2:10.08 | |
| 25 | 2 | Raquel Meaños | ESP | 2:10.13 | |
| 26 | 2 | Freja Wærness | DEN | 2:10.50 | |
| 27 | 4 | Caitlyn Collier | USA | 2:11.30 | Q |
| 28 | 4 | Isabelle Boffey | GBR | 2:11.43 | Q |
| 29 | 4 | Milena Korbut | POL | 2:11.52 | Q |
| 30 | 3 | Carolina Hernandez-Pita | SUI | 2:11.52 | |
| 31 | 4 | Majtie Kolberg | GER | 2:11.61 | Q |
| 32 | 4 | Sanne Njaastad | NOR | 2:11.82 | |
| 33 | 4 | María Lasa | ESP | 2:12.04 | |
| 34 | 2 | Aurora Rynda | CAN | 2:12.31 | |
| 35 | 1 | Veera Perälä | FIN | 2:12.38 | |
| 36 | 3 | Haley Walker | CAN | 2:12.76 | |
| 37 | 4 | Shyamali Kumarasingha | SRI | 2:12.91 | |
| 38 | 2 | Albina Deliu | KOS | 2:19.84 | |
| 5 | Linda Philip Mamun | ART | | |
Semifinals
Qualification: First 2 of each heat and the 2 fastest times qualified for the final.
| Rank | Heat | Name | Nationality | Time | Note |
| 1 | 2 | Diribe Welteji | ETH | 2:01.89 | Q |
| 2 | 1 | Freweyni Hailu | ETH | 2:01.96 | Q |
| 3 | 1 | Delia Sclabas | SUI | 2:02.12 | Q, |
| 4 | 3 | Carley Thomas | AUS | 2:03.19 | Q, |
| 5 | 2 | Katy-Ann McDonald | GBR | 2:03.20 | Q, |
| 6 | 3 | Gabriela Gajanová | SVK | 2:03.36 | Q, |
| 7 | 3 | Ayaka Kawata | JPN | 2:03.37 | q |
| 8 | 1 | Jackline Wambui | KEN | 2:03.44 | q, |
| 9 | 2 | Ayano Shiomi | JPN | 2:03.72 | |
| 10 | 3 | Caitlyn Collier | USA | 2:03.95 | |
| 11 | 1 | Samantha Watson | USA | 2:03.95 | |
| 12 | 2 | Lydia Jeruto Lagat | KEN | 2:04.59 | |
| 13 | 2 | Jemima Russell | AUS | 2:04.81 | |
| 14 | 3 | Maeliss Trapeau | FRA | 2:05.35 | |
| 15 | 3 | Marharyta Kachanava | BLR | 2:06.53 | |
| 16 | 3 | Milena Korbut | POL | 2:06.60 | |
| 17 | 2 | Eloisa Coiro | ITA | 2:06.85 | |
| 18 | 1 | Jo Keane | IRL | 2:06.91 | |
| 19 | 1 | Shaquena Foote | JAM | 2:08.02 | |
| 20 | 2 | Camille Muls | BEL | 2:08.16 | |
| 21 | 1 | Federica Cortesi | ITA | 2:09.85 | |
| 22 | 2 | Majtie Kolberg | GER | 2:10.66 | |
| 23 | 3 | Chrissani May | JAM | 2:10.70 | |
| 24 | 1 | Isabelle Boffey | GBR | 2:11.49 | |
Final
