The women's 800 metre freestyle event at the 2005 World Aquatics Championships took place between 29 July – 30 July. The heats were held on 29 July and the final was held on 30 July.

Records

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

	Name	Nationality	Time	Location	Date
World record	Janet Evans Janet Evans Janet Beth Evans is a American competitive swimmer who specializes in distance freestyle. She recently announced her comeback to the sport with intentions to swim in the 2012 Olympic Trials.-Biography:...	United States United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	8:16.22	Tokyo Tokyo , ; officially , is one of the 47 prefectures of Japan. Tokyo is the capital of Japan, the center of the Greater Tokyo Area, and the largest metropolitan area of Japan. It is the seat of the Japanese government and the Imperial Palace, and the home of the Japanese Imperial Family...	20 August 1989
Championship record	Hannah Stockbauer Hannah Stockbauer Hannah Stockbauer is a German female athlete. She is active in swimming, and a five time world champion. In 2003 World Championships she won a gold medal at the 400 m, 800 m and 1500 m freestyle events...	Germany Germany Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...	8:23.66	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

No new world or competition records were set during this competition.

Final

Rank	Name	Nationality	Time	Notes
	Kate Ziegler Kate Ziegler Kate Marie Ziegler is an American long-distance swimmer. She currently holds the world record in the 1500-meter freestyle ....		8:25.31
	Brittany Reimer Brittany Reimer Brittany Reimer is a former Canadian long-distance swimmer. She is a two-time medallist at the World Aquatics Championships and competed at the 2004 Summer Olympics.-Career:...		8:27.59
	Ai Shibata Ai Shibata is a Japanese swimmer. At the 2004 Summer Olympics, she won the gold medal in the 800 meter freestyle race and became the first ever female gold medalist for Japan in a freestyle event....		8:27.86
4	Flavia Rigamonti Flavia Rigamonti Flavia Rigamonti is a Swiss swimmer from Sorengo. As of 2010, she holds the Swiss Records in the women's 400, 800 and 1500 freestyles.At the 2007 World Championships, she set the European Record in the women's 1500 free ....		8:28.74
5	Camelia Potec Camelia Potec Camelia Potec is a female Romanian swimmer, who won the gold medal in the women's 200 m freestyle final at the 2004 Summer Olympics.She won the Mare Nostrum in 2004.-References:* *...		8:34.40
6	Erika Villaeciji		8:36.34
7	Rebecca Cooke Rebecca Cooke Rebecca Cooke is a former British freestyle swimmer.She has won medals at every major international championships with the exception of the Olympic Games. She retired from international competition in April 2008 after failing to make the British team for the 2008 Games in Beijing.-References:...		8:37.98
8	Jana Henke Jana Henke Jana Henke is a former freestyle swimmer from Germany, who won the bronze medal in the 800 m freestyle at the 1992 Summer Olympics in Barcelona, Spain. She competed in three Summer Olympics for her native country....		8:38.23