Billed as "the UK's biggest mass participation open water swimming series", the Great Swim was started in 2008 with a one mile Great North Swim in Windermere. Taking its inspiration from the world’s biggest half marathon the Great North Run, and the idea of Long Distance swimmer Colin Hill who was working for Nova international, Great Swim uses the formula of mass participation events to provide a focus and a challenge for which the individual can train.
After the success of the inaugural Great North Swim on 14 September 2008, which attracted over 2,200 swimmers of all ages and abilities (including five of the six Olympic Open Water Medallists), the series was expanded in 2009 to 4 events and added the title sponsor of British Gas. The Great London Swim took place for the first time on 15 August 2009 in Royal Victoria Dock. The Great Scottish Swim took place on Saturday 29 August 2009 at Strathclyde Park, followed by the Great North Swim on 12 and 13 September 2009 and finally the Great East Swim on Saturday 26 September in Alton Water. Over 6,000 swimmers registered for the Great North Swim in 2009, and nearly 4,600 recorded a finishing time for the one mile distance. Over the 4 events in 2009, over 6,700 swimmers were recorded as having completed the distance.
In 2010 the series was extended to include an event in Salford Quays, all events were televised on Channel 4 with hour shows dedicted to each event, with the main focus on the elite races. In addition, 500m swims have been added to the program at each venue as well as a 2 mile swim in Windermere called The Great North Swim the Extra Mile. However, 2010 saw the cancellation of both the Great Scottish and Great North Swims due to the presence of a controversial amount of blue-green algae at both sites, leaving several thousand swimmers disappointed.
2011, however had 10,000 swimmers sign up to the British Gas Great North Swim, held over 3 days and included two mile, one mile and half mile events. The British Gas Great Salford Swim was shown live on BBC. 2011 Head of Great Swim, Colin Hill, left Nova International to work for the London 2012 Olympics as Marathon Swimming Technical Operations Manager.
Each event features an elite race for women and another elite race for men, followed by a series of "waves" of swimmers with up to 200 swimmers in a wave. The course is GPS calibrated to ensure that the exact distance of one mile is covered and each competitor is electronically timed with a chip strapped to the ankle.
Although not specifically a charity swim, many participants raised money for a range of charities. Specific charity partners are nominated for each event (and sometimes are able to provide entries) but no restrictions are in place around fund-raising.