World record progression 400 metres freestyle

The first world record in the men's 400 metres freestyle in long course (50 metres) swimming was recognised by the International Swimming Federation (FINA) in 1908. In the short course (25 metres) swimming events the world's governing body recognizes world records since 3 March 1991.

Long course

 * Murray Rose's 4:25.9 set in a 25-metre pool on 12 Jan 1957 was only valid until 1 May the same year. Due to the new rule that records must be set in a 50-metre pool, and the fact that neither John Marshall's 4:26.9 from 1951, nor Ford Konno's 4:26.7 from 1954 were set in 50-metre pools, the WR reverted to Rose's 4:27.0 from 1956.
 * Paul Biedermann's 3:40.07 set at the 2009 World Aquatics Championships was swum utilising the Arena X-Glide suit. A style of suit that was introduced in 2008 and banned by FINA in January 2010.

Men long course

 * Correct as of June 2024

Men short course

 * Correct as of December 2023

Women long course

 * Correct as of June 2024

Women short course

 * Correct as of December 2023