The Women's 800-metre freestyle competition at the 2019 World Championships was held on 26 and 27 July 2019.

[1][2] Defending champion Katie Ledecky successfully defended her title in 8:13.58 with a final lap comeback against Italy's Simona Quadarella.

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

The heats were started on 26 July at 12:05.

[4] The final was started on 27 July at 21:25.