| Intelligent Auto Ltd | Wholesale & retail | 2020 |
| Inter Partners Ltd | Professional & scientific | 2025 |
| Intergold Industrial Ltd | Other services | 2010 |
| Interior Design Cladding Ltd | Manufacturing | 2023 |
| Interlink (NE) Ltd | Wholesale & retail | 2012 |
| Internal Growth Ltd | Health & social care | 2022 |
| International Concessionaires Limited | Extraterritorial | 1979 |
| International Flooring Consultancy Limited | Administrative & support | 2020 |
| Internet Distribution Highway Limited | Transport & logistics | 1999 |
| Intersect Architects Limited | Professional & scientific | 2010 |
| Interval Coffee Ltd | Hospitality | 2017 |
| Intrabizz Ltd | Professional & scientific | 2005 |
| Intruder Detection & Surveillance Ltd. | Construction | 1999 |
| INTUITIV3 Limited | Information & communication | 2019 |
| Invest MAG Limited | Administrative & support | 2014 |
| Investment Properties & Lettings Limited | Real estate | 2010 |
| Investmental Ltd | Real estate | 2015 |
| Involved and Equal CIC | Education | 2022 |
| ION Energy Limited | Professional & scientific | 2021 |
| Ionic Events Limited | Arts & recreation | 2017 |
| IP Fabrication Services Limited | Manufacturing | 2026 |
| Irent Ltd | Real estate | 2015 |
| Irewamiri Ltd | Information & communication | 2019 |
| Irheat Ltd | Construction | 2023 |
| Iris Digital Solutions LLP | | 2014 |
| Iris Law Firm Limited | Professional & scientific | 2009 |
| Iris Law LLP | | 2010 |
| Ironhaven Wealth Management Ltd | Financial services | 2018 |
| Irons Developments (North) Ltd | Construction | 2025 |
| Irons Group Ltd | Financial services | 2024 |
| Irons Homes Ltd | Construction | 2025 |
| Ironstone Electronics Ltd | Information & communication | 2019 |
| Iroofs Ltd | Construction | 2025 |
| Irrigonics Limited | Water & waste | 2004 |
| Irwin Wright Limited | Financial services | 2026 |
| IS Medical Limited | Health & social care | 2022 |
| Isabel Homes Ltd | Real estate | 2026 |
| Isabella Crawford Ltd | Other services | 2025 |
| ISJ Properties (Northern) Limited | Construction | 2010 |
| Island Fire & Security Limited | Construction | 2023 |
| Islestone Holdings Ltd | Financial services | 2025 |
| Islestone Limited | Wholesale & retail | 2009 |
| Isley Properties Limited | Real estate | 2024 |
| Ismo Foodies Ltd | Wholesale & retail | 2025 |
| Iswjc Holdings Limited | Financial services | 2025 |
| IT Assist North East Limited | Information & communication | 2012 |
| IT Blueprints Ltd. | Information & communication | 2012 |
| Itaipava Martial Arts Bedlington Ltd | Arts & recreation | 2023 |
| Itengineering Ltd | Professional & scientific | 2025 |
| Itransformly Ltd | Education | 2025 |
| Ittan Limited | Other services | 2022 |
| Iveston Developments Limited | Construction | 2021 |
| IW Maintenance Ltd | Administrative & support | 2026 |
| Iwaniuk Consultancy Ltd | Extraterritorial | 2023 |
| Iykyk Medical Group Limited | Other services | 2025 |
| Iykyk Silvenir's Ltd | Arts & recreation | 2023 |
| Izuu Ltd | Wholesale & retail | 2026 |
| J & B Properties North East Limited | Real estate | 2019 |
| J & D Estates Ltd | Real estate | 2004 |
| J & H Contracting Ltd | Information & communication | 2014 |
| J & J Charitable Trust Limited | Real estate | 2011 |
| J & M Oils Ltd | Wholesale & retail | 2024 |
| J C Robson Limited | Health & social care | 2026 |
| J D Services (NE) Ltd | Administrative & support | 2025 |
| J Foster Private Prosthetics Limited | Health & social care | 2001 |
| J Mazurkiewicz Ltd | Health & social care | 2014 |
| J N Logistics N.E Ltd | Water & waste | 2020 |
| J R Energy Services Ltd | Manufacturing | 2019 |
| J R Rental Properties Ltd | Real estate | 2025 |
| J Simpson and Family Ltd | Hospitality | 2021 |
| J W Dickinson Ltd | Construction | 2015 |
| J&A Shrub and Plant Centre Ltd | Wholesale & retail | 2019 |
| J&J Autos (North East) Limited | Manufacturing | 2019 |
| J&L Inns Limited | Hospitality | 2024 |
| J&L NE Limited | Wholesale & retail | 2022 |
| J&S Joinery (North East) Limited | Administrative & support | 2017 |
| J&S Property Maintenance NE Limited | Construction | 2024 |
| J-Mec Engineering Ltd | Construction | 2020 |
| J-Mec Projects Ltd | Construction | 2024 |
| J-Seva 1 Limited | Hospitality | 2024 |
| J-Seva 2 Limited | Hospitality | 2024 |
| J-Seva 3 Limited | Hospitality | 2024 |
| J-Seva 4 Limited | Hospitality | 2024 |
| J. Freeman & Sons Limited | Wholesale & retail | 2001 |
| J. R. Freeman & Co. (Estates) Limited | Real estate | 1988 |
| J.A. Crescent Dental Care Limited | Health & social care | 2006 |
| J.D.J (North East) Limited | Construction | 2009 |
| J.E.T 2000 Limited | Transport & logistics | 2010 |
| J.I.V Edumoh's Services Limited | Health & social care | 2019 |
| J.J. Bruen & Sons Group Ltd | Financial services | 2024 |
| J.M.M. Building & Civil Engineering Limited | Construction | 2006 |
| J.R. Holland (Food Services) Limited | Hospitality | 1995 |
| J.S Sons Construction Limited | Construction | 2025 |
| JA Potts Logistics Ltd | Transport & logistics | 2025 |
| JA Property Group (NE) Ltd | Real estate | 2025 |
| JAC Installations Ltd | Construction | 2018 |
| Jachlo Limited | Other services | 2023 |
| Jack Charles Ltd | Real estate | 2024 |
| Jackie of ALL Trades Limited | Wholesale & retail | 2025 |
| Jacobsfield Ltd | Real estate | 2021 |