| Impekzine Ltd | Transport & logistics | 2020 |
| Impellico Facilities Management Limited | Administrative & support | 2021 |
| Imperative Global Ltd | Administrative & support | 2021 |
| Imperial Capital Israel Limited | Financial services | 2014 |
| Imperial Cars (Southampton) Limited | Transport & logistics | 2003 |
| Imperial Facades Ltd | Construction | 2018 |
| Imperial Hats Ltd | Wholesale & retail | 2024 |
| Imperial Homes Commercial Ltd | Real estate | 2019 |
| Imperial Homes South Group Limited | Financial services | 2022 |
| Imperial Homes South Limited | Real estate | 2017 |
| Imperial Homes Southern Counties Ltd | Construction | 2017 |
| Imperial Partnerships Limited | Construction | 2025 |
| Imperial Property Sourcing Solutions Limited | Hospitality | 2026 |
| Imperial Residential Investments Limited | Construction | 2024 |
| Imperial Traffic Management Ltd | Construction | 2021 |
| Imperial Warehouse Limited | Wholesale & retail | 2018 |
| Imperium Corporate Services Limited | Administrative & support | 2016 |
| Impero Marketing Ltd | Extraterritorial | 2010 |
| Impress (South) Limited | Wholesale & retail | 2015 |
| Impress Energy Limited | Professional & scientific | 2012 |
| Impress Products Limited | Professional & scientific | 2007 |
| Impress Property Management Limited | Real estate | 2020 |
| Impress Travel Limited | Administrative & support | 2019 |
| Impromptu Services Limited | Information & communication | 2025 |
| Improve PD Limited | Information & communication | 2026 |
| Improvised Solutions Limited | Information & communication | 2000 |
| IMR Property Limited | Real estate | 2025 |
| IMX Projects Limited | Professional & scientific | 2014 |
| IN Common Southampton Ltd | Information & communication | 2020 |
| IN One Accord Ltd | Information & communication | 2024 |
| IN Play Capital Ltd | Administrative & support | 2024 |
| IN the Game Productions Limited | Information & communication | 2023 |
| IN Touch HRM Ltd | Administrative & support | 2013 |
| In-Crowd Security Ltd | Administrative & support | 2025 |
| In-Vision Media Group Ltd | Information & communication | 2024 |
| IN2 Bathrooms Limited | Wholesale & retail | 2009 |
| INA Estates Ltd | Real estate | 2024 |
| Inalio Ltd | Wholesale & retail | 2019 |
| Inbound to Anglia Ltd | Wholesale & retail | 2017 |
| Inboxtor Ltd | Information & communication | 2025 |
| Inbusiness Accountants Limited | Professional & scientific | 2012 |
| Inca Design Limited | Professional & scientific | 2005 |
| Incidental Finding Limited | Arts & recreation | 2016 |
| Inclusive Minds Psychology Limited | Education | 2024 |
| Inco Alloys Limited | Professional & scientific | 1999 |
| Incorporated Beauty Limited | Wholesale & retail | 2010 |
| Incorporating Media Ltd. | Administrative & support | 2009 |
| Increase Your Social Reach Ltd | Professional & scientific | 2018 |
| Incrementum Consulting Ltd | Professional & scientific | 2023 |
| IND Projects Ltd | Professional & scientific | 2022 |
| Inde Viis Surfacing Ltd | Construction | 2019 |
| Independent Car & Van Servicing Limited | Wholesale & retail | 2012 |
| Independent Climbing Wall Collective CIC | Arts & recreation | 2025 |
| Independent Fashion Ltd | Administrative & support | 2018 |
| Independent Investment Holdings Limited | Financial services | 2025 |
| Independent Living Support Centre Limited | Administrative & support | 2026 |
| Independent Marketing Ltd | Professional & scientific | 2000 |
| Independent Plumbing Supplies Ltd | Wholesale & retail | 2013 |
| Independent Port Handling Limited | Wholesale & retail | 2007 |
| Independent Pro-Vision Ltd | Financial services | 2020 |
| Independent Yacht Consultants (IYC) Ltd | Professional & scientific | 2011 |
| Inderkitchen UK Limited | Wholesale & retail | 2009 |
| Index Europe Limited | Other services | 2025 |
| India Business Consultancy Limited | Professional & scientific | 2014 |
| India Business Group Limited | Education | 2025 |
| India Delta Consulting Limited | Information & communication | 2020 |
| Indian Balti House Limited | Hospitality | 2025 |
| Indian Food Factory Ltd | Hospitality | 2019 |
| Indian Kitchen Street Food Limited | Hospitality | 2024 |
| Indian Rose 1 Ltd | Hospitality | 2022 |
| Indian Tadka Ltd | Hospitality | 2026 |
| Indie Ltd | Hospitality | 2025 |
| Indigo Digiprint Limited | Manufacturing | 2021 |
| Indigo Integrated Solutions Limited | Information & communication | 2010 |
| Indigo River Investments Ltd | Real estate | 2024 |
| Individually Designed Solutions Ltd | Financial services | 1992 |
| Indo Lighting Ltd | Manufacturing | 2025 |
| Indo Technologies Ltd | Manufacturing | 2024 |
| Indoor Property Solutions Ltd | Construction | 2025 |
| Indulgence Services Ltd | Professional & scientific | 2018 |
| Industrial Cadets Ltd | Education | 2014 |
| Industrial Cleaning Equipment (Southampton) Ltd | Wholesale & retail | 1992 |
| Industrial Finds Ltd | Wholesale & retail | 2018 |
| Industrial Investments Ukeig | | 2017 |
| Industrial Noise Reduction Limited | Manufacturing | 2000 |
| Industrial Profiles Limited | Manufacturing | 2004 |
| Industrial Superstore Limited | Wholesale & retail | 2000 |
| Industrial Things Ltd | Extraterritorial | 2020 |
| Industrial Ventilation Products Limited | Manufacturing | 1997 |
| Industrial Ventilation Projects Limited | Construction | 1997 |
| Inertech Waste Consultancy Limited | Water & waste | 2013 |
| Inertech Waste Management Limited | Professional & scientific | 2023 |
| Inex Coatings Ltd | Construction | 2026 |
| Inex Construction Limited | Construction | 2001 |
| Infinigreen Limited | Construction | 2021 |
| Infinite Accountancy Limited | Professional & scientific | 2021 |
| Infinite OL Belgravia Ltd | Wholesale & retail | 2026 |
| Infinite Social Care Ltd | Health & social care | 2022 |
| Infinite Socials Limited | Professional & scientific | 2025 |
| Infiniti Bookkeeping & Accountancy Limited | Professional & scientific | 2024 |