Anderson has represented Great Britain at the Paralympic Games on six occasions, in 1992, 1996, 2000, 2004, 2008 and the 2012 Summer Paralympics. He has won six Paralympic gold medals, four at the 2004 Games, in the 50 m, 100 m and 200 m freestyle and the 50 m backstroke events, and two at the 1996 Games in the 50 m backstroke and 100 m freestyle races. He has also set two world records and four European records. He also competed at the 2008 Paralympics in Beijing. He was selected again for the 2012 Paralympics in London, finishing fourth in the S2 class final of the 50m backstroke and eighth in the S2 100m freestyle.