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

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

The heats were held on 24 July at 10:00.^[3]

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
	4	7	Kierra Smith	Canada		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
	5	8	Zhang Xinyu	China
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
	3	1	Evita Leter	Suriname
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

The semifinals were started on 24 July at 17:58.^[4]

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

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

The final was held on 25 July at 19:17.^[5]

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