The women's 100 metre breaststroke event at the 2005 World Aquatics Championships took place between 30 July – 31 July. Both the heats and semifinals were held on 30 July with the heats being held in the morning session and the semifinals being held in the evening session. The final was held on 31 July.

Records

Prior to the competition, the existing world and championship records were as follows.

	Name	Nationality	Time	Location	Date
World record	Zoë Baker Zoë Baker Zoë Baker is a former world record holder in swimming who represented Great Britain until 2005 and now represents New Zealand.Baker represented England at the 2002 Commonwealth Games in Manchester winning the gold medal in the women's 50 m breaststroke in a time of 30.60 seconds...	Great Britain Great Britain Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...	30.57	Manchester Manchester Manchester is a city and metropolitan borough in Greater Manchester, England. According to the Office for National Statistics, the 2010 mid-year population estimate for Manchester was 498,800. Manchester lies within one of the UK's largest metropolitan areas, the metropolitan county of Greater...	30 July 2002
Championship record	Luo Xuejuan Luo Xuejuan Luo Xuejuan is a female Chinese swimmer, who competed mostly in the breaststroke. She is a former World Record holder in swimming, and in some meet results she is listed as "LUO Xue Juan".-Career:...	China China Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...	30.64	Barcelona Barcelona Barcelona is the second largest city in Spain after Madrid, and the capital of Catalonia, with a population of 1,621,537 within its administrative limits on a land area of...	26 July 2003

The following records were established during the competition:

Date	Round	Name	Nationality	Time	WR	CR
July 30	Semifinals	Jade Edmistone Jade Edmistone Jade Edmistone is an Australian breaststroke swimmer, who is the former world-record holder in the 50 m breaststroke at both short and long course formats of the event. She is coached by Stephan Widmar at the Commercial Swim Club in Brisbane...	Australia Australia Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...	30.61		CR
July 31	Final	Jade Edmistone Jade Edmistone Jade Edmistone is an Australian breaststroke swimmer, who is the former world-record holder in the 50 m breaststroke at both short and long course formats of the event. She is coached by Stephan Widmar at the Commercial Swim Club in Brisbane...	Australia Australia Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...	30.45	WR	CR

Final

Rank	Name	Nationality	Time	Notes
	Jade Edmistone Jade Edmistone Jade Edmistone is an Australian breaststroke swimmer, who is the former world-record holder in the 50 m breaststroke at both short and long course formats of the event. She is coached by Stephan Widmar at the Commercial Swim Club in Brisbane...		30.45	WR
	Jessica Hardy Jessica Hardy Jessica Adele Hardy is an American swimmer who specializes in the breaststroke and freestyle stroke. She currently holds the world record in the 50 m breaststroke and the 100 m breaststroke ....		30.85
	Brooke Hanson Brooke Hanson Brooke Louise Hanson OAM is a former Australian swimmer.A swimmer since the age of four, Hanson was the youngest swimmer on the Australian national team at the 1994 Commonwealth Games, where she finished fourth in the 200 m breaststroke...		30.89
4	Tara Kirk Tara Kirk Tara Kirk is a former American swimmer who specialized in the breaststroke and Olympic silver medalist. She is a former world record holder in the 100-meter breaststroke ....		31.38
5	Zoë Baker Zoë Baker Zoë Baker is a former world record holder in swimming who represented Great Britain until 2005 and now represents New Zealand.Baker represented England at the 2002 Commonwealth Games in Manchester winning the gold medal in the women's 50 m breaststroke in a time of 30.60 seconds...		31.43
6	Kate Haywood Kate Haywood Kate Emma Haywood is an English swimmer. She was the youngest swimmer to represent England in the Commonwealth Games when she qualified for the 2002 Commonwealth Games in Manchester, where she won a bronze medal in the 4×100 m medley relay...		31.49
7	Luo Xuejuan Luo Xuejuan Luo Xuejuan is a female Chinese swimmer, who competed mostly in the breaststroke. She is a former World Record holder in swimming, and in some meet results she is listed as "LUO Xue Juan".-Career:...		31.50
8	Janne Schaefer		32.45

Key: WR = World record