| Haymarket Investments Limited | Construction | 1956 |
| Heaven Hair & Beauty Limited | Other services | 2005 |
| Heckington Petroleum Co. Limited | Real estate | 2007 |
| Hemsby Beach Self Catering Holidays Limited | Hospitality | 1985 |
| Herts Insurance Consultants Limited | Financial services | 1999 |
| Hethel Investments Limited | Real estate | 2005 |
| Heydon Enterprises Limited | Other services | 2025 |
| Hi-Span Limited | Manufacturing | 1939 |
| Highline Holdings Limited | Professional & scientific | 2007 |
| Hiken Limited | Manufacturing | 2003 |
| Hitchens (Solutions) Limited | Professional & scientific | 2003 |
| HM Kestrel Rentals Ltd | Real estate | 2021 |
| Hmtm Baker Consultancy Limited | Professional & scientific | 2024 |
| Hobbs Close (Wells-Next-The-Sea) Management Company Limited | Households | 2024 |
| Hobson Associates Limited | Administrative & support | 2002 |
| Holden & Holden Limited | Wholesale & retail | 1978 |
| Holden Motors Limited | Wholesale & retail | 1972 |
| Holiday Properties(Mundesley)Limited | Hospitality | 1957 |
| Holkham Emerald Limited | Agriculture & fishing | 2008 |
| Holkham Farming Company Limited | Agriculture & fishing | 1996 |
| Holkham Holiday Parks Limited | Hospitality | 2019 |
| Hollie Godden Photography Limited | Professional & scientific | 2025 |
| Homes by Design UK Ltd | Construction | 2007 |
| Homestead House Limited | Health & social care | 1999 |
| Homestyle Fitted Furniture Limited | Manufacturing | 1989 |
| Hong Kong Stratton Ltd | Hospitality | 2022 |
| Horizon Estimating Services Ltd | Construction | 2022 |
| Horizon Helicrew Ltd | Professional & scientific | 2015 |
| Horstead Construction Limited | | 1976 |
| Houghton Russell LLP | | 2012 |
| Howard Burgess Limited | Real estate | 2004 |
| Howards Cycles Limited | Wholesale & retail | 2003 |
| Hudson Property Services Limited | Real estate | 1992 |
| Hunter's Fleet Limited | Hospitality | 1996 |
| Hy-Tek (Engineering Services) Limited | Manufacturing | 1992 |
| HYT805S Ltd | Wholesale & retail | 2025 |
| I W Investments Limited | Real estate | 1972 |
| I.D. Asbestos Ltd | Construction | 2001 |
| I.T.S. Services Ltd | Manufacturing | 2004 |
| Iain S Devine & Partners Limited | Professional & scientific | 2007 |
| IAN Couzens Limited | Professional & scientific | 2001 |
| IAN Williamson & SON (Kings Lynn) Limited | Professional & scientific | 1978 |
| Iceni Leather | | 1987 |
| Iconikk Coaching Ltd | Arts & recreation | 2024 |
| Imon Site Ltd | Agriculture & fishing | 2002 |
| Imperial Car Breakers Limited | Wholesale & retail | 2018 |
| Impress Sutton Ltd | Manufacturing | 1922 |
| Impreza Breakers Limited | Wholesale & retail | 2008 |
| Incatern Limited | Arts & recreation | 1987 |
| India Village (Norfolk) Ltd | Hospitality | 2021 |
| Indian Summer Foods Limited | Hospitality | 2025 |
| Industry Offshore Onshore Limited | Manufacturing | 1990 |
| Infinity Emea Limited | Other services | 2017 |
| Information Channel Limited | Professional & scientific | 1999 |
| Inspection & Technical Research Services Limited | | 1982 |
| Instrument Machining Service Limited | Manufacturing | 1961 |
| Invisible Vision Ltd | Manufacturing | 2006 |
| IO Group Management Limited | | 1992 |
| Iona Networks Limited | Information & communication | 1998 |
| Isometric Bar Ltd | Wholesale & retail | 2024 |
| J F T Clark Limited | Agriculture & fishing | 1998 |
| J L Roofing Ltd | Construction | 2007 |
| J Neale Limited | Health & social care | 2007 |
| J Nudds Shellfish Ltd | Agriculture & fishing | 2005 |
| J S P Leisure Ltd | Arts & recreation | 1999 |
| J Taylor Construction Ltd | Construction | 2021 |
| J W Mason Limited | Health & social care | 2007 |
| J&A Boutique Ltd | Wholesale & retail | 2022 |
| J. & J. Shellfish Limited | Agriculture & fishing | 1984 |
| J. Power Photography Ltd | Professional & scientific | 2006 |
| J.B. Postle & SON Limited | Wholesale & retail | 1961 |
| J.C. Quantrell and Sons Limited | Other services | 1979 |
| J.E. Owles Limited | Agriculture & fishing | 1958 |
| J.F.Temple & SON Limited | Agriculture & fishing | 1956 |
| J.K. Bowles (Winterton) Ltd | Real estate | 2003 |
| Jack Richards & SON Limited | Transport & logistics | 1972 |
| Jack Richards (Storage) Limited | Extraterritorial | 1967 |
| Jack Richards Holdings Limited | Professional & scientific | 2006 |
| Jack Sayers Products Limited | Manufacturing | 1979 |
| James Browne Developments LLP | | 2004 |
| Jane Wasden Limited | Professional & scientific | 2000 |
| Janith Homes Limited | Health & social care | 1985 |
| Jarrold & Sons Limited | Wholesale & retail | 1902 |
| Jarrold Facilities Management Limited | Administrative & support | 2003 |
| Jaymic Limited | Wholesale & retail | 2004 |
| JBT Electrical Ltd | Construction | 2018 |
| JCM Baker Ltd | Real estate | 2025 |
| JDC Corporate Finance Limited | Extraterritorial | 2005 |
| Jellylane Environmental Services Limited | Arts & recreation | 2006 |
| JIM Russell | | 2003 |
| Jims Butchers Limited | Wholesale & retail | 2003 |
| JM Batchelor Holdings Limited | Financial services | 2018 |
| JO Bedford Entertainments Ltd | Arts & recreation | 2026 |
| Jodan Investments Limited | Wholesale & retail | 2003 |
| Joe's Tattoo Studio Ltd | Arts & recreation | 2003 |
| John Blake T/A Breckland Farriers Ltd | Agriculture & fishing | 2004 |
| John Booty Building Services Limited | Construction | 2003 |
| John Jarrold Trust Limited | Administrative & support | 1965 |
| John Oliver (PW) Ltd | Other services | 2003 |
| John Oliver Partnerships Limited | Other services | 1993 |