| Band | Formed / started | Split up / ended | Note |
|---|---|---|---|
| I Am Giant | 1 October 2008 | 2018 | — |
| I Am Jack | 2000 | — | — |
| I Am Kloot | 1999 | — | English rock band |
| I Drive | 1967 | 1973 | — |
| I Like Trains | 2003 | — | — |
| I Was a Cub Scout | June 2005 | 14 July 2008 | — |
| I, Ludicrous | 4 February 1985 | — | — |
| Ian Dury & the Kilburns | 1972 | — | — |
| Ian Gillan Band | 1975 | 1978 | — |
| Iconic Memory | 1994 | — | — |
| IDER | 2015 | — | — |
| IDLES | 2009 | — | — |
| Idlewild | December 1995 | — | Scottish indie rock band |
| If | 1969 | 1975 | — |
| Ihlo | June 2016 | — | — |
| Ikara Colt | 1999 | January 2005 | — |
| ILL | 6 April 2012 | — | — |
| Ill Gotten Gains | 2013 | — | — |
| Imagination | 1981 | — | English soul/funk band |
| Imbalance | 1995 | 2002 | — |
| Imindain | 2002 | — | — |
| Immaculate Fools | 1984 | 1997 | — |
| Impaler | 1990 | — | — |
| Imperium | 2010 | — | — |
| In Cahoots | 1982 | — | — |
| In Crooked Wonderment | 20 April 2024 | — | — |
| In Excelsis | 1983 | 1985 | — |
| In Vino Veritas | 2005 | — | — |
| Incision | 1997 | 4 August 2001 | — |
| Incognito | 1979 | — | UK acid jazz band |
| Inconcessus Lux Lucis | 2009 | — | — |
| Incredible Hog | 1972 | 1973 | — |
| Indecent Exposure | 1981 | — | — |
| Indesinence | 2001 | 19 November 2015 | — |
| Indica | 1999 | 2005 | — |
| Indica Blues | 2014 | — | — |
| Indigo Daydream | 15 March 2021 | — | — |
| Infadels | 2003 | 1 September 2012 | — |
| Infant Bile | 2005 | — | — |
| Infested Angel | 2019 | — | — |
| Infobia | 2001 | — | — |
| Ingested | 2002 | — | — |
| Inkubus Sukkubus | 1989 | — | — |
| Inner City Unit | April 1979 | 1986 | — |
| Insecure Men | 2016 | — | — |
| Inspiral Carpets | 1989 | — | — |
| Intestinal Infestation | 1988 | — | — |
| Intra Tenebrae | 2008 | — | — |
| Iona | 1990 | — | Celtic folk/rock band from the United Kingdom |
| IQ | 1981 | — | British progressive rock band |
| Iroha | 2008 | — | — |
| Iron Claw | 1969 | 1974 | Scotish hard rock band |
| Iron Grave | 9 June 2012 | — | — |
| Iron Maiden | 25 December 1975 | — | English heavy metal band |
| Iron Monkey | 1994 | 1999 | — |
| Is Tropical | 2009 | — | — |
| Isen Torr | 2003 | — | — |
| It Bites | 1982 | — | — |
| It’s Immaterial | 1980 | 1990 | — |