# Swimming at the 2017 World Aquatics Championships – Women's 100 metre breaststroke

The Women's 100 metre breaststroke competition at the 2017 World Championships was held on 24 and 25 July 2017.

## Records

Prior to the competition, the existing world and championship records were as follows.
| World record | Rūta Meilutytė (LTU) | 1:04.35 | Barcelona, Spain | 29 July 2013 |
| Competition record | Rūta Meilutytė (LTU) | 1:04.35 | Barcelona, Spain | 29 July 2013 |
The following new records were set during this competition.
| Date | Event | Name | Nationality | Time | Record |
| 25 July | Final | Lilly King | United States | 1:04.13 | WR, CR |

## Results
### Heats

The heats were held on 24 July at 10:00.
| Rank | Heat | Lane | Name | Nationality | Time | Notes |
| 1 | 5 | 4 | Lilly King | United States | 1:05.20 | Q |
| 2 | 6 | 4 | Yuliya Yefimova | Russia | 1:05.60 | Q |
| 3 | 6 | 5 | Rūta Meilutytė | Lithuania | 1:05.81 | Q |
| 4 | 4 | 4 | Katie Meili | United States | 1:06.39 | Q |
| 5 | 5 | 2 | Taylor McKeown | Australia | 1:06.64 | Q |
| 6 | 4 | 3 | Jessica Vall | Spain | 1:06.85 | Q |
| 7 | 5 | 5 | Shi Jinglin | China | 1:06.94 | Q |
| 8 | 6 | 2 | Rachel Nicol | Canada | 1:07.10 | Q |
| 9 | 6 | 1 | Jessica Hansen | Australia | 1:07.12 | Q |
| 10 | 4 | 6 | Satomi Suzuki | Japan | 1:07.20 | Q |
| 10 | 6 | 7 | Sarah Vasey | Great Britain | 1:07.20 | Q |
| 12 | 6 | 3 | Siobhan-Marie O'Connor | Great Britain | 1:07.33 | Q, WD |
| 13 | 4 | 5 | Jennie Johansson | Sweden | 1:07.35 | Q |
| 14 | 5 | 6 | Rikke Møller Pedersen | Denmark | 1:07.39 | Q |
| 15 | 4 | 1 | Arianna Castiglioni | Italy | 1:07.43 | Q |
| 15 | 4 | 7 | Kierra Smith | Canada | 1:07.43 | Q |
| 17 | 4 | 2 | Reona Aoki | Japan | 1:07.48 | Q |
| 18 | 6 | 6 | Hrafnhildur Lúthersdóttir | Iceland | 1:07.54 | |
| 19 | 6 | 9 | Martina Moravčíková | Czech Republic | 1:07.69 | |
| 20 | 6 | 8 | Jenna Laukkanen | Finland | 1:07.83 | |
| 21 | 5 | 7 | Natalia Ivaneeva | Russia | 1:07.97 | |
| 22 | 5 | 3 | Martina Carraro | Italy | 1:08.11 | |
| 23 | 5 | 0 | Macarena Ceballos | Argentina | 1:08.34 | |
| 24 | 4 | 8 | Mona McSharry | Ireland | 1:08.52 | |
| 25 | 4 | 0 | Anna Sztankovics | Hungary | 1:08.66 | |
| 26 | 3 | 4 | Maria Romanjuk | Estonia | 1:08.81 | NR |
| 26 | 5 | 8 | Zhang Xinyu | China | 1:08.81 | |
| 28 | 6 | 0 | Dominika Sztandera | Poland | 1:09.91 | |
| 29 | 3 | 5 | Natasha Lloyd | New Zealand | 1:10.11 | |
| 30 | 5 | 9 | Andrea Podmaníková | Slovakia | 1:10.13 | |
| 31 | 4 | 9 | Kaylene Corbett | South Africa | 1:10.16 | |
| 32 | 5 | 1 | Viktoriya Zeynep Güneş | Turkey | 1:10.30 | |
| 33 | 3 | 3 | Mariya Liver | Ukraine | 1:10.49 | |
| 34 | 3 | 2 | Alina Bulmag | Moldova | 1:10.89 | |
| 35 | 3 | 6 | Rebecca Kamau | Kenya | 1:11.61 | |
| 36 | 2 | 5 | Tilka Paljk | Zambia | 1:12.65 | NR |
| 37 | 3 | 0 | Amy Micallef | Malta | 1:12.79 | NR |
| 38 | 2 | 3 | Lei On Kei | Macau | 1:14.11 | |
| 39 | 3 | 7 | Dariya Talanova | Kyrgyzstan | 1:14.13 | |
| 40 | 3 | 9 | Vanessa Rivas | Dominican Republic | 1:14.14 | |
| 41 | 1 | 5 | Nguyễn Thị Nhất Lam | Vietnam | 1:15.99 | |
| 42 | 3 | 8 | Meri Mumladze | Georgia | 1:16.70 | NR |
| 43 | 2 | 4 | Nawapas Pisanuwong | Thailand | 1:16.91 | |
| 44 | 1 | 6 | Honia Ibrahim | Iraq | 1:17.48 | NR |
| 44 | 3 | 1 | Evita Leter | Suriname | 1:17.48 | |
| 46 | 1 | 4 | Batbayaryn Enkhkhuslen | Mongolia | 1:18.70 | NR |
| 47 | 1 | 3 | Jang Myong-gyong | North Korea | 1:18.87 | |
| 48 | 2 | 6 | Oreoluwa Cherebin | Grenada | 1:18.91 | |
| 49 | 2 | 2 | Melisa Zhdrella | Kosovo | 1:21.47 | NR |
| 50 | 1 | 2 | Elen Yesayan | Armenia | 1:21.84 | NR |
| 51 | 2 | 0 | Tilali Scanlan | American Samoa | 1:23.03 | NR |
| 52 | 2 | 9 | Tisa Shakya | Nepal | 1:26.13 | NR |
| 53 | 2 | 8 | Sajina Aishath | Maldives | 1:28.92 | |
| — | 2 | 1 | Maayaa Ayawere | Ghana | DNS | DNS |

### Semifinals

The semifinals were started on 24 July at 17:58.

#### Semifinal 1

| Rank | Lane | Name | Nationality | Time | Notes |
| 1 | 4 | Yuliya Yefimova | Russia | 1:04.36 | Q, NR |
| 2 | 5 | Katie Meili | United States | 1:05.48 | Q |
| 3 | 3 | Jessica Vall | Spain | 1:06.62 | Q |
| 4 | 6 | Rachel Nicol | Canada | 1:07.03 | |
| 5 | 2 | Satomi Suzuki | Japan | 1:07.08 | |
| 6 | 1 | Arianna Castiglioni | Italy | 1:07.19 | |
| 7 | 8 | Reona Aoki | Japan | 1:07.43 | |
| 8 | 7 | Jennie Johansson | Sweden | 1:07.93 | |

#### Semifinal 2

| Rank | Lane | Name | Nationality | Time | Notes |
| 1 | 4 | Lilly King | United States | 1:04.53 | Q |
| 2 | 5 | Rūta Meilutytė | Lithuania | 1:05.06 | Q |
| 3 | 6 | Shi Jinglin | China | 1:06.47 | Q |
| 4 | 8 | Kierra Smith | Canada | 1:06.62 | Q |
| 5 | 7 | Sarah Vasey | Great Britain | 1:06.81 | Q |
| 6 | 3 | Taylor McKeown | Australia | 1:06.93 | |
| 7 | 2 | Jessica Hansen | Australia | 1:07.21 | |
| 8 | 1 | Rikke Møller Pedersen | Denmark | 1:07.92 | |

### Final

The final was held on 25 July at 19:17.
| Rank | Lane | Name | Nationality | Time | Notes |
| | 5 | Lilly King | United States | 1:04.13 | WR |
| | 6 | Katie Meili | United States | 1:05.03 | |
| | 4 | Yuliya Yefimova | Russia | 1:05.05 | |
| 4 | 3 | Rūta Meilutytė | Lithuania | 1:05.65 | |
| 5 | 2 | Shi Jinglin | China | 1:06.43 | |
| 6 | 1 | Kierra Smith | Canada | 1:06.90 | |
| 7 | 7 | Jessica Vall | Spain | 1:06.95 | |
| 8 | 8 | Sarah Vasey | Great Britain | 1:07.19 | |