The BBC Big Splash campaign receives backing from legendary United States swimmer Mark Spitz, who won nine Olympic gold medals in a glittering career, including seven golds at the Munich Games in 1972.
The Big Splash Mile for Sport Relief is a brand new fundraising event that will take place during the Swimathon weekend on the 27-29 April 2012.
Swimmers can take part individually or as part of a team to complete the mile.
The event will be hosted in 600 pools across the UK and will provide people with a personal challenge, a goal to train and great causes to support.
To register your interest or to find out more go to the official Swimathon site.
For more information on how you can get involved with swimming, visit the Big Splash website.