# 2018 FINA World Swimming Championships (25 m) – Women's 100 metre individual medley

The women's 100 metre individual medley competition of the 2018 FINA World Swimming Championships (25 m) was held on 13 and 14 December 2018.

## Records

Prior to the competition, the existing world and championship records were as follows.
| | Name | Nation | Time | Location | Date |
| World record | Katinka Hosszú | Hungary | 56.51 | Berlin | 7 August 2017 |
| Championship record | Katinka Hosszú | Hungary | 56.70 | Doha | 5 December 2014 |

## Results
### Heats

The heats were started on 13 December at 10:06.
| Rank | Heat | Lane | Name | Nationality | Time | Notes |
| 1 | 4 | 4 | Katinka Hosszú | Hungary | 58.05 | Q |
| 2 | 4 | 3 | Melanie Margalis | United States | 58.87 | Q |
| 3 | 3 | 5 | Runa Imai | Japan | 58.99 | Q |
| 4 | 4 | 5 | Emily Seebohm | Australia | 59.11 | Q |
| 5 | 3 | 3 | Ye Shiwen | China | 59.24 | Q |
| 6 | 4 | 6 | Jenna Laukkanen | Finland | 59.39 | Q |
| 7 | 3 | 6 | Rika Omoto | Japan | 59.48 | Q |
| 8 | 3 | 4 | Kathleen Baker | United States | 59.52 | Q |
| 9 | 2 | 4 | Alia Atkinson | Jamaica | 59.69 | Q |
| 10 | 3 | 2 | Ilaria Cusinato | Italy | 59.76 | Q |
| 11 | 2 | 5 | Maria Kameneva | Russia | 59.78 | Q |
| 12 | 2 | 6 | Lena Kreundl | Austria | 59.94 | Q |
| 13 | 3 | 8 | Rūta Meilutytė | Lithuania | 1:00.11 | Q |
| 14 | 3 | 7 | Lidón Muñoz del Campo | Spain | 1:00.71 | Q |
| 15 | 2 | 3 | Susann Bjørnsen | Norway | 1:00.82 | Q |
| 16 | 2 | 2 | Yang Chang | China | 1:01.24 | Q |
| 17 | 3 | 0 | Marie Pietruschka | Germany | 1:01.34 | |
| 18 | 4 | 2 | Anastasiia Sorokina | Russia | 1:01.47 | |
| 19 | 2 | 7 | Kan Cheuk Tung Natalie | Hong Kong | 1:01.49 | |
| 20 | 4 | 7 | Kristýna Horská | Czech Republic | 1:01.60 | |
| 21 | 4 | 1 | Viktoriya Zeynep Güneş | Turkey | 1:01.66 | |
| 22 | 4 | 0 | Diana Petkova | Bulgaria | 1:01.75 | |
| 23 | 3 | 1 | Jessica Vall | Spain | 1:01.79 | |
| 24 | 1 | 4 | Neža Klančar | Slovenia | 1:01.87 | |
| 25 | 2 | 8 | Rebecca Meder | South Africa | 1:01.93 | |
| 26 | 2 | 1 | Ieva Maļuka | Latvia | 1:01.94 | |
| 27 | 3 | 9 | Raquel Gomes Pereira | Portugal | 1:02.07 | |
| 28 | 4 | 8 | Seraina Sturzenegger | Switzerland | 1:02.10 | |
| 29 | 2 | 9 | Andrea Podmaníková | Slovakia | 1:02.77 | |
| 30 | 4 | 9 | Margaret Markvardt | Estonia | 1:02.99 | |
| 31 | 2 | 0 | Julia Sebastián | Argentina | 1:03.16 | |
| 32 | 1 | 5 | Georgina McCarthy | New Zealand | 1:04.50 | |
| 33 | 1 | 3 | Nicole Rautemberg | Paraguay | 1:05.04 | |
| 34 | 1 | 0 | Sara Pastrana | Honduras | 1:07.96 | |
| 35 | 1 | 8 | Nooran Ba-Matraf | Yemen | 1:08.53 | |
| 36 | 1 | 2 | Latroya Pina | Cape Verde | 1:09.99 | |
| 37 | 1 | 6 | Avice Meya | Uganda | 1:13.51 | |
| 38 | 1 | 7 | Alex Maclaren | Turks and Caicos Islands | 1:19.83 | |
| 39 | 1 | 1 | Aishath Sausan | Maldives | 1:19.91 | |

### Semifinals

The semifinals were started on 13 December at 20:06.

#### Semifinal 1

| Rank | Lane | Name | Nationality | Time | Notes |
| 1 | 4 | Melanie Margalis | United States | 58.33 | Q |
| 2 | 6 | Kathleen Baker | United States | 58.54 | Q |
| 3 | 3 | Jenna Laukkanen | Finland | 58.60 | Q |
| 4 | 5 | Emily Seebohm | Australia | 58.64 | Q |
| 5 | 7 | Lena Kreundl | Austria | 59.46 | |
| 6 | 2 | Ilaria Cusinato | Italy | 59.85 | |
| 7 | 1 | Lidón Muñoz del Campo | Spain | 1:00.69 | |
| 8 | 8 | Yang Chang | China | 1:00.86 | |

#### Semifinal 2

| Rank | Lane | Name | Nationality | Time | Notes |
| 1 | 4 | Katinka Hosszú | Hungary | 57.69 | Q |
| 2 | 5 | Runa Imai | Japan | 58.04 | Q |
| 3 | 2 | Alia Atkinson | Jamaica | 58.20 | Q |
| 4 | 6 | Rika Omoto | Japan | 58.60 | Q |
| 5 | 3 | Ye Shiwen | China | 58.94 | |
| 6 | 7 | Maria Kameneva | Russia | 58.97 | |
| 7 | 1 | Rūta Meilutytė | Lithuania | 59.81 | |
| 7 | 1 | Susann Bjørnsen | Norway | 1:01.04 | |

### Final

The final was held on 14 December at 19:20.
| Rank | Lane | Name | Nationality | Time |
| | 4 | Katinka Hosszú | Hungary | 57.26 |
| | 5 | Runa Imai | Japan | 57.85 |
| | 3 | Alia Atkinson | Jamaica | 58.11 |
| 4 | 6 | Melanie Margalis | United States | 58.32 |
| 5 | 2 | Kathleen Baker | United States | 58.47 |
| 6 | 8 | Emily Seebohm | Australia | 58.78 |
| 7 | 7 | Jenna Laukkanen | Finland | 59.11 |
| 8 | 1 | Rika Omoto | Japan | 59.18 |