# Swimming at the 2020 Summer Olympics – Women's 100 metre breaststroke

The women's 100 metre breaststroke event at the 2020 Summer Olympics was held from 25 July to 27 July 2021 at the Tokyo Aquatics Centre. It was the event's fourteenth consecutive appearance, having been held at every edition since 1968.

## Summary

The U.S.' teen Lydia Jacoby upset South Africa's Tatjana Schoenmaker and defending champion Lilly King to capture the sprint breaststroke title. Hanging with the leaders at the turn, Jacoby broke away over the final 20 metres to win gold by almost three tenths of a second in 1:04.95. With the performance, Jacoby became just the sixth woman in history to break the 1:05 barrier. First at the turn, Schoenmaker could not contend with Jacoby's blistering final lap and settled for silver in a time of 1:05.22, 0.4 seconds shy off her Olympic record in the heats. Meanwhile, Jacoby's teammate and 2016 champion Lilly King was 0.03 seconds ahead of Jacoby at the turn but could not fend off the youngster's charge, taking bronze in 1:05.54.
ROC's Evgeniia Chikunova delivered a time of 1:05.90 to pick up the fourth spot, just ahead of teammate and defending silver medallist Yuliya Yefimova (1:06.02) by about a tenth of a second. Sweden's Sophie Hansson placed sixth in 1:06.07, while Martina Carraro (1:06.19) and Ireland's Mona McSharry (1:06.94) rounded out the championship field.

## Records

Prior to this competition, the existing world and Olympic records were as follows.
| World record | Lilly King (USA) | 1:04.13 | Budapest, Hungary | 25 July 2017 |
| Olympic record | Lilly King (USA) | 1:04.93 | Rio de Janeiro, Brazil | 8 August 2016 |
The following records were established during the competition:
| Date | Event | Swimmer | Nation | Time | Record |
| July 25 | Heat 5 | Tatjana Schoenmaker | South Africa | 1:04.82 | OR |

## Qualification

The Olympic Qualifying Time for the event is 1:07.07. Up to two swimmers per National Olympic Committee (NOC) can automatically qualify by swimming that time at an approved qualification event. The Olympic Selection Time is 1:09.08. Up to one swimmer per NOC meeting that time is eligible for selection, allocated by world ranking until the maximum quota for all swimming events is reached. NOCs without a female swimmer qualified in any event can also use their universality place.

## Competition format

The competition consisted of three rounds: heats, semifinals, and a final. The swimmers with the best 16 times in the heats advanced to the semifinals. The swimmers with the best 8 times in the semifinals advanced to the final. Swim-offs are used as necessary to break ties for advancement to the next round.

## Schedule

All times are Japan Standard Time (UTC+9)
| Date | Time | Round |
| 25 July | 19:34 | Heats |
| 26 July | 10:50 | Semifinals |
| 27 July | 11:17 | Final |

## Results
### Heats

The swimmers with the top 16 times, regardless of heat, advanced to the semifinals.
| Rank | Heat | Lane | Swimmer | Nation | Time | Notes |
| 1 | 5 | 5 | Tatjana Schoenmaker | South Africa | 1:04.82 | Q, OR, AF |
| 2 | 5 | 4 | Lydia Jacoby | United States | 1:05.52 | Q |
| 3 | 6 | 4 | Lilly King | United States | 1:05.55 | Q |
| 4 | 6 | 5 | Sophie Hansson | Sweden | 1:05.66 | Q, NR |
| 5 | 6 | 3 | Martina Carraro | Italy | 1:05.85 | Q |
| 6 | 6 | 6 | Evgeniia Chikunova | ROC | 1:06.16 | Q |
| 7 | 6 | 8 | Ida Hulkko | Finland | 1:06.19 | Q, NR |
| 8 | 4 | 4 | Yuliya Yefimova | ROC | 1:06.21 | Q |
| 9 | 5 | 6 | Mona McSharry | Ireland | 1:06.39 | Q |
| 10 | 4 | 3 | Tang Qianting | China | 1:06.47 | Q |
| 11 | 6 | 2 | Sarah Vasey | Great Britain | 1:06.61 | Q |
| 12 | 5 | 3 | Chelsea Hodges | Australia | 1:06.70 | Q |
| 13 | 5 | 7 | Lisa Mamié | Switzerland | 1:06.76 | Q |
| 14 | 5 | 2 | Eneli Jefimova | Estonia | 1:06.79 | Q |
| 15 | 3 | 1 | Kotryna Teterevkova | Lithuania | 1:06.82 | Q |
| 16 | 3 | 2 | Anna Elendt | Germany | 1:06.96 | Q |
| 17 | 4 | 2 | Kanako Watanabe | Japan | 1:07.01 | |
| 18 | 5 | 1 | Jessica Vall | Spain | 1:07.07 | |
| 19 | 4 | 6 | Reona Aoki | Japan | 1:07.29 | |
| 20 | 4 | 1 | Jessica Hansen | Australia | 1:07.50 | |
| 21 | 4 | 7 | Alina Zmushka | Belarus | 1:07.58 | |
| 22 | 3 | 6 | Alia Atkinson | Jamaica | 1:07.70 | |
| 23 | 4 | 8 | Kelsey Wog | Canada | 1:07.73 | |
| 24 | 6 | 7 | Kierra Smith | Canada | 1:07.87 | |
| 25 | 3 | 4 | Tes Schouten | Netherlands | 1:07.89 | |
| 26 | 3 | 5 | Fanny Lecluyse | Belgium | 1:07.93 | |
| 27 | 6 | 1 | Emelie Fast | Sweden | 1:07.98 | |
| 28 | 2 | 3 | Andrea Podmaníková | Slovakia | 1:08.36 | NR |
| 29 | 2 | 5 | Phee Jinq En | Malaysia | 1:08.40 | NR |
| 30 | 3 | 7 | Melissa Rodríguez | Mexico | 1:08.76 | |
| 31 | 3 | 3 | Julia Sebastián | Argentina | 1:09.35 | |
| 32 | 2 | 7 | Tilali Scanlan | American Samoa | 1:10.01 | |
| 33 | 2 | 4 | Ema Rajić | Croatia | 1:10.02 | |
| 34 | 3 | 8 | Diana Petkova | Bulgaria | 1:10.61 | |
| 35 | 2 | 6 | Emily Santos | Panama | 1:12.10 | |
| 36 | 2 | 8 | Kirsten Fisher-Marsters | Cook Islands | 1:13.98 | |
| 37 | 1 | 3 | Emilie Grand'Pierre | Haiti | 1:14.82 | NR |
| 38 | 2 | 2 | Alicia Kok Shun | Mauritius | 1:15.42 | |
| 39 | 1 | 5 | Darya Semyonova | Turkmenistan | 1:16.37 | |
| 40 | 1 | 4 | Jayla Pina | Cape Verde | 1:16.96 | |
| 41 | 1 | 2 | Taeyanna Adams | Federated States of Micronesia | 1:25.36 | |
| 42 | 1 | 7 | Nooran Ba-Matraf | Yemen | 1:27.79 | |
| 43 | 1 | 6 | Aishath Sajina | Maldives | 1:33.59 | |
| — | 2 | 1 | Claudia Verdino | Monaco | DSQ | |
| — | 4 | 5 | Benedetta Pilato | Italy | DSQ | |
| — | 1 | 1 | Mariama Toure | Guinea | DNS | |
| — | 5 | 8 | Anastasia Gorbenko | Israel | DNS | |

### Semifinals

The swimmers with the best 8 times, regardless of heat, advanced to the final.
| Rank | Heat | Lane | Swimmer | Nation | Time | Notes |
| 1 | 2 | 4 | Tatjana Schoenmaker | South Africa | 1:05.07 | Q |
| 2 | 2 | 5 | Lilly King | United States | 1:05.40 | Q |
| 3 | 1 | 4 | Lydia Jacoby | United States | 1:05.72 | Q |
| 4 | 1 | 5 | Sophie Hansson | Sweden | 1:05.81 | Q |
| 5 | 1 | 6 | Yuliya Yefimova | ROC | 1:06.34 | Q |
| 6 | 1 | 3 | Evgeniia Chikunova | ROC | 1:06.47 | Q |
| 7 | 2 | 3 | Martina Carraro | Italy | 1:06.50 | Q |
| 8 | 2 | 2 | Mona McSharry | Ireland | 1:06.59 | Q |
| 9 | 1 | 7 | Chelsea Hodges | Australia | 1:06.60 | |
| 10 | 1 | 2 | Tang Qianting | China | 1:06.63 | |
| 11 | 2 | 7 | Sarah Vasey | Great Britain | 1:06.87 | |
| 12 | 2 | 6 | Ida Hulkko | Finland | 1:07.02 | |
| 13 | 1 | 8 | Anna Elendt | Germany | 1:07.31 | |
| 14 | 2 | 8 | Kotryna Teterevkova | Lithuania | 1:07.39 | |
| 15 | 2 | 1 | Lisa Mamié | Switzerland | 1:07.41 | |
| 16 | 1 | 1 | Eneli Jefimova | Estonia | 1:07.58 | |

### Final

| Rank | Lane | Swimmer | Nation | Time |
| | 3 | Lydia Jacoby | United States | 1:04.95 |
| | 4 | Tatjana Smith | South Africa | 1:05.22 |
| | 5 | Lilly King | United States | 1:05.54 |
| 4 | 7 | Evgeniia Chikunova | ROC | 1:05.90 |
| 5 | 2 | Yuliya Yefimova | ROC | 1:06.02 |
| 6 | 6 | Sophie Hansson | Sweden | 1:06.07 |
| 7 | 1 | Martina Carraro | Italy | 1:06.19 |
| 8 | 8 | Mona McSharry | Ireland | 1:06.94 |