| Intellstra Limited | Information & communication | 2024 |
| Interlock Adhesives Limited | Wholesale & retail | 1993 |
| Internetspecs Ltd | Wholesale & retail | 2026 |
| Intj Computer Services Limited | Professional & scientific | 2025 |
| Investech Holdings Ltd | Professional & scientific | 2019 |
| Investforme Limited | Financial services | 2024 |
| INVESTING4YOU Limited | Financial services | 2020 |
| Invictus Therapy Ltd | Education | 2020 |
| Invidia Scooters Limited | Wholesale & retail | 2008 |
| IO Nutrition and Lifestyle Ltd | Health & social care | 2026 |
| ION Trades Ltd | Wholesale & retail | 2025 |
| Ionita I&A Ltd | Transport & logistics | 2024 |
| Ionut Bena Ltd | Transport & logistics | 2020 |
| Iosua Eremia Transport Ltd | Transport & logistics | 2025 |
| Iosua International Ltd | Wholesale & retail | 2024 |
| IP Surveys Limited | Professional & scientific | 2022 |
| Ipfclinic LLP | | 2020 |
| IPS Communications Limited | Information & communication | 2014 |
| IR Capital Estate Ltd | Real estate | 2024 |
| Irimia Ltd | Transport & logistics | 2022 |
| Iron Barbers Ltd | Other services | 2025 |
| Iron Freaks Gym and Fitness Ltd | Arts & recreation | 2020 |
| Iron Locks Ltd | Wholesale & retail | 2022 |
| Ironbird Scaffolding Ltd | Construction | 2025 |
| Ironmastersco CIC | Education | 2025 |
| Ironstone Plant Hire Ltd | Administrative & support | 2016 |
| Ironstone Vehicle Sales Ltd | Wholesale & retail | 2026 |
| Isabellaglow Training Ltd | Education | 2024 |
| Isac M Transport Ltd | Transport & logistics | 2025 |
| Isaiah & Co. Ltd | Wholesale & retail | 2023 |
| Isla-Grace Properties Limited | Real estate | 2025 |
| Island House & Supply Company Ltd | Wholesale & retail | 2025 |
| Island Legal Limited | Health & social care | 2016 |
| Isle Building Supplies Ltd | Wholesale & retail | 2026 |
| Isle Construction (Lincolnshire) Ltd | Construction | 2019 |
| Isle Country Show CIC | Arts & recreation | 2025 |
| Isle Design IT Limited | Information & communication | 2015 |
| Isle of Axholme Masonic Hall Limited | Other services | 1959 |
| Isle Travel Limited | Information & communication | 2019 |
| Isma Homes Limited | Construction | 2022 |
| Isolation Solutions Ltd | Construction | 2026 |
| Istanbul Barber 158 Ltd | Other services | 2022 |
| It's E.J's Cars Ltd | Transport & logistics | 2010 |
| IT-SERVICES4U Ltd. | Information & communication | 2017 |
| IUI Chillies Ltd | Wholesale & retail | 2026 |
| Ivy-Rose Tanning Ltd | Other services | 2025 |
| IW Dowson Limited | Agriculture & fishing | 2017 |
| J & K Skinner Properties Ltd | Real estate | 2021 |
| J & L Hull Properties Limited | Real estate | 2024 |
| J & M Machining Services Limited | Manufacturing | 2002 |
| J & M MEX Store Ltd | Wholesale & retail | 2018 |
| J & M Woodall Limited | Transport & logistics | 2017 |
| J & N Thomas Limited | Financial services | 2021 |
| J & T Emporium Ltd | Wholesale & retail | 2025 |
| J Bugo Medical Ltd | Health & social care | 2023 |
| J C Plumbing & Heating (Scunthorpe) Limited | Construction | 2021 |
| J C Properties (Scunthorpe) Ltd | Real estate | 2021 |
| J D FOX Consulting Limited | Information & communication | 2024 |
| J Daniel Haulage Limited | Transport & logistics | 2016 |
| J Farnham Limited | Other services | 2011 |
| J FOX GAS Ltd | Construction | 2017 |
| J G Wilkinson Limited | Manufacturing | 2002 |
| J Hanson Motors Ltd | Wholesale & retail | 2018 |
| J Kennedy Holdings Limited | Financial services | 2026 |
| J L Electrical Solutions Ltd | Construction | 2022 |
| J L Welsh Limited | Professional & scientific | 2019 |
| J Noble Chiropractic Ltd | Health & social care | 2023 |
| J R Walker Services Limited | Professional & scientific | 2019 |
| J S Associates (Scunthorpe) Limited | Professional & scientific | 2022 |
| J S Convenience Limited | Wholesale & retail | 2026 |
| J Site Services Ltd | Construction | 2026 |
| J T W Entertainment Limited | Wholesale & retail | 2023 |
| J Twells Electrical Limited | Construction | 2019 |
| J Watts Ltd | Wholesale & retail | 2008 |
| J Wright Joinery Services Ltd | Manufacturing | 2023 |
| J&J Marshall Limited | Real estate | 2024 |
| J&J Prestige Ltd | Real estate | 2026 |
| J&M Dwellings Limited | Real estate | 2025 |
| J&P Auto Care Ltd | Wholesale & retail | 2025 |
| J&S Places for People Ltd | Real estate | 2025 |
| J. Hill Engineering Ltd | Transport & logistics | 2012 |
| J. MAW & SON (Haulage) Limited | Transport & logistics | 2003 |
| J. Mono Electrical Limited | Construction | 2007 |
| J. Mono Properties Ltd | Real estate | 2025 |
| J.A. 4 Services Ltd | Transport & logistics | 2026 |
| J.Boulton Plumbing & Heating Ltd | Energy | 2024 |
| J.C. Holland (Northern) Limited | Construction | 1971 |
| J.H. Joinery Services Ltd | Construction | 2006 |
| J.J.&D.S.Stubley Limited | Agriculture & fishing | 1955 |
| J.Kar Ltd | Transport & logistics | 2025 |
| J.R. Glew Junior & Co. Limited | Agriculture & fishing | 1976 |
| J.Young Limited | Construction | 2020 |
| J@Ck Transport Limited | Transport & logistics | 2025 |
| Jaaz 2010 Limited | Hospitality | 2025 |
| Jack Commercial Services Limited | Professional & scientific | 2019 |
| Jack Tighe Coatings Limited | Construction | 1981 |
| Jack Tighe Decorating Limited | Construction | 1996 |
| Jack Tighe Holdings Limited | Professional & scientific | 1983 |
| Jack Tighe Limited | Construction | 1965 |
| Jack Tighe Scunthorpe Limited | Construction | 1996 |