| Iimmps Limited | Professional & scientific | 2025 |
| IK Smile Ltd | Health & social care | 2025 |
| Ikigai Overlap Holdings Ltd | Financial services | 2025 |
| Ikigia Coaching & Consulting Ltd | Professional & scientific | 2025 |
| Ilasuk Limited | Transport & logistics | 2018 |
| Ilford Football Club Ltd | Extraterritorial | 2024 |
| Immenzza Ltd | Information & communication | 2023 |
| Imperative Property Ltd | Real estate | 2018 |
| Imperial Paving Solutions Ltd | Administrative & support | 2023 |
| Imperial Trade and Finance Ltd | Wholesale & retail | 2021 |
| Imported Alcohol Limited | Wholesale & retail | 2019 |
| Impressions Hair & Beauty Limited | Other services | 2010 |
| Improving the Donington Environment for ALL | Other services | 2003 |
| In-Touch Group Holdings Limited | Financial services | 2022 |
| Inchoo Ventures Limited | Administrative & support | 2014 |
| Inchst LLP | | 2023 |
| Incluro Ltd | Professional & scientific | 2024 |
| Inclusive Business Services Limited | Information & communication | 2024 |
| Incomize Digital Ltd | Information & communication | 2026 |
| Independent Cargo Supervision Ltd | Transport & logistics | 2024 |
| Independent European Certification Ltd. | Other services | 1996 |
| Independent Event Management Limited | Administrative & support | 2011 |
| Independent Recruitment Limited | Administrative & support | 2016 |
| Independent Roofing Consultant Ltd | Construction | 2025 |
| Indie House Limited | Professional & scientific | 2003 |
| Industrial Rollers Limited | Wholesale & retail | 2018 |
| Industrotech Fmcg Project Engineering Ltd | Construction | 2022 |
| Industrotech Ltd | Manufacturing | 2014 |
| Industrotech Training Centres Ltd | Education | 2022 |
| Infichem Ltd | Wholesale & retail | 2015 |
| Information Technology Limited | Information & communication | 2026 |
| Infotel Solutions Limited | Administrative & support | 2001 |
| Infotrans Computing Limited | Information & communication | 1998 |
| Inglis Capital Limited | Extraterritorial | 2026 |
| Ingram Asset Management Company Limited | Real estate | 2021 |
| Ingrams Soft Washing Ltd | Administrative & support | 2024 |
| Ingreda Transport Ltd | Transport & logistics | 2016 |
| Inittive Limited | Information & communication | 2023 |
| Inkjet Investments Limited | Other services | 2024 |
| Innovation Profits Limited | Professional & scientific | 2015 |
| Inpes Limited | Construction | 2018 |
| Inpromptu Engineering Limited | Professional & scientific | 2016 |
| Instantbuddies Ltd | Health & social care | 2025 |
| Intech Accountancy Limited | Professional & scientific | 2018 |
| Integrity Foods Limited | Manufacturing | 2017 |
| Integrity Healthcare Ltd | Extraterritorial | 2021 |
| Intelligent Drives Limited | Manufacturing | 2004 |
| Inter TL Transport Ltd | Transport & logistics | 2022 |
| Interiology Limited | Professional & scientific | 2007 |
| Interiorology Limited | Administrative & support | 2004 |
| International Development Services Limited | Construction | 2023 |
| Internet Electrical Ltd | Information & communication | 1998 |
| Interntrans Ltd | Transport & logistics | 2017 |
| Intersolv Ltd | Manufacturing | 2025 |
| Inversiones Pantin Ltd | Wholesale & retail | 2025 |
| Inversiones Talavante Ltd | Wholesale & retail | 2025 |
| Inverted Motion Ltd | Professional & scientific | 2025 |
| Iodetail Ltd | Transport & logistics | 2024 |
| Ioli Trans Ltd | Transport & logistics | 2014 |
| Ione Trans Limited | Transport & logistics | 2015 |
| IP Lettings.Com Limited | Real estate | 2017 |
| IRC Investments Limited | Financial services | 2019 |
| Irrigationxpress Limited | Wholesale & retail | 2023 |
| IS Trans Ltd | Transport & logistics | 2014 |
| Island Girl Kitchen Ltd | Manufacturing | 2025 |
| ISM Consulting Limited | Construction | 2025 |
| Istanbul Spalding Ltd | Hospitality | 2018 |
| Itsgone Limited | Information & communication | 2005 |
| Iuliu Ltd | Transport & logistics | 2024 |
| Iurie and SON Ltd | Manufacturing | 2021 |
| Iurie Construction Ltd | Construction | 2019 |
| Ivanda Nursery Limited | Agriculture & fishing | 2005 |
| IVE Removals Ltd | Transport & logistics | 2023 |
| Ivera International Ltd | Information & communication | 2025 |
| IZA Kopec Ltd | Transport & logistics | 2020 |
| J & a Properties Limited | Administrative & support | 2011 |
| J & a Saxton Management Limited | Households | 2017 |
| J & B Hollingsworth Services Limited | Transport & logistics | 2019 |
| J & B Industrial Services Ltd | Administrative & support | 2017 |
| J & B Roofing Services Ltd | Construction | 2026 |
| J & D Betts Plumbing Services Limited | Construction | 2019 |
| J & D Driving Ltd | Transport & logistics | 2024 |
| J & D Landscapes Ltd | Construction | 2017 |
| J & J Thorpe Ltd | Real estate | 2025 |
| J & L Developers (Lincolnshire) Limited | Real estate | 2000 |
| J & L Groundworks Ltd | Construction | 2018 |
| J & M Auto Services (Spalding) Ltd | Wholesale & retail | 2014 |
| J & M Concrete Limited | Administrative & support | 2014 |
| J & N Transport Services Limited | Transport & logistics | 2008 |
| J a Salon Ltd | Other services | 2026 |
| J a Sandall Ltd | Transport & logistics | 2014 |
| J a Watts Limited | Agriculture & fishing | 2015 |
| J and H Paving and Roofing Ltd | Administrative & support | 2024 |
| J B Anlegg Ltd | Construction | 2026 |
| J B Autos (Lincs) Limited | Wholesale & retail | 2010 |
| J B Robinson and SON Limited | Agriculture & fishing | 2012 |
| J Baines Ltd | Administrative & support | 2018 |
| J Baxter Services Ltd | Transport & logistics | 2025 |
| J C Carpets (Lincs) Ltd | Construction | 2018 |
| J C T Biogas Limited | Construction | 2018 |