| Iphigenia Limited | Other services | 2019 |
| IQ Technologies Ltd | Wholesale & retail | 2024 |
| Iqbi Data Solutions Ltd | Information & communication | 2020 |
| Irakli Ltd | Transport & logistics | 2022 |
| Irem Foods Limited | Hospitality | 2026 |
| Irfa Incorporation Limited | Wholesale & retail | 2025 |
| Irfan UL Huda Travels UK Limited | Administrative & support | 2025 |
| Irha & Inseya Limited | Manufacturing | 2026 |
| Irha Mart Limited | Wholesale & retail | 2026 |
| Irlichanov Limited | Professional & scientific | 2014 |
| Iron Bridge Move Management Ltd | Transport & logistics | 2024 |
| Iron Key Ltd | Real estate | 2024 |
| Ironclad Security Group Limited | Wholesale & retail | 2025 |
| Irong Art Ltd | Arts & recreation | 2026 |
| Irons Elite Training Ltd | Arts & recreation | 2010 |
| IRR Limited | Real estate | 2022 |
| Irsa Beauté Ltd | Other services | 2026 |
| Irsa Yasir Vegs Ltd | Wholesale & retail | 2023 |
| Irtiz Limited | Wholesale & retail | 2025 |
| Isaac a & Sons Company Limited | Wholesale & retail | 2017 |
| ISE2323 Limited | Construction | 2022 |
| Ishe-Anesu PVT Ltd | Health & social care | 2016 |
| Ishraq Land Property Limited | Real estate | 2021 |
| ISI Unicorn Ltd | Hospitality | 2024 |
| Isma Beauty Limited | Wholesale & retail | 2025 |
| Issim Properties Ltd | Real estate | 2024 |
| Istiqama Ltd | Professional & scientific | 2024 |
| IT Block Limited | Information & communication | 2015 |
| IT Paradise Ltd | Information & communication | 2010 |
| IT Skills London Limited | Other services | 2025 |
| IT Takes Two London Ltd | Arts & recreation | 2024 |
| Itech & Hometex UK Ltd | Wholesale & retail | 2023 |
| Iteck Bazaar Ltd | Other services | 2024 |
| Itemizor Limited | Wholesale & retail | 2024 |
| Itgoals Ltd | Information & communication | 2014 |
| Itinfy Limited | Professional & scientific | 2009 |
| ITRAIN2 Ltd. | Information & communication | 2012 |
| Itso Creative Ltd | Wholesale & retail | 2020 |
| Itsynbitsy Ltd | Wholesale & retail | 2025 |
| IUA Services Limited | Administrative & support | 2023 |
| Iulia Services Ltd | Transport & logistics | 2022 |
| Iulicer Ltd | Construction | 2004 |
| Iurca Ltd | Transport & logistics | 2021 |
| Iurcu Services Limited | Administrative & support | 2025 |
| IV Painting Services Ltd | Construction | 2022 |
| IVET2006 Ltd | Information & communication | 2022 |
| IVI 2020 Ltd | Construction | 2020 |
| Ivitraplus Healthcare Ltd | Public administration | 2024 |
| Ivo-G Ltd | Construction | 2014 |
| Ivofix Ltd | Construction | 2017 |
| IVY Travel Group Ltd | Administrative & support | 2025 |
| IVY UK Motors Limited | Wholesale & retail | 2024 |
| Iwinosa & Co (UK) Limited | Health & social care | 2018 |
| Iwollo Omashi UK Limited | Education | 2024 |
| Iyaaro Services Limited | Health & social care | 2020 |
| Iyekoretin Property Limited | Real estate | 2026 |
| Iyin Technologies Limited | Information & communication | 2025 |
| IZA Hairstyle Ltd | Other services | 2025 |
| Izabela Francesca Ltd | Construction | 2026 |
| Izan Consultancy Limited | Information & communication | 2016 |
| Izzi and Dough Ltd. | Manufacturing | 2018 |
| Izzz Properties Limited | Real estate | 2023 |
| J & a IT Consultancy Limited | Professional & scientific | 2013 |
| J & G Electrical Services Limited | Construction | 1999 |
| J & J Bandesha's Ltd | Construction | 2022 |
| J & M Loft Conversion Ltd | Construction | 2021 |
| J & S Quality Services Ltd | Health & social care | 2021 |
| J Gigg Electrical Limited | Construction | 2021 |
| J Motun UK Limited | Health & social care | 2019 |
| J Saule Barbers Limited | Other services | 2014 |
| J Top Class Barber Ltd | Other services | 2025 |
| J Verai Ltd | Wholesale & retail | 2025 |
| J&A Shehu Construction Ltd | Construction | 2025 |
| J&Blocations Ltd | Real estate | 2022 |
| J&D Sterling Construction Ltd | Construction | 2026 |
| J&G Building Solutions Limited | Construction | 2021 |
| J&J Stonework Ltd | Construction | 2025 |
| J&J Style Hub Ltd | Wholesale & retail | 2024 |
| J&K Sharmas Ltd | Other services | 2024 |
| J&M Collections Ltd | Administrative & support | 2024 |
| J&M Rendering Solutions Ltd | Construction | 2025 |
| J&T Decorators Ltd | Construction | 2021 |
| J&Z Medical Limited | Health & social care | 2022 |
| J-Furniture Ltd | Other services | 2011 |
| J. Barros Ltd | Transport & logistics | 2025 |
| J. Mcevilly Limited | Real estate | 1995 |
| J. O. Nsiah Construction Limited | Construction | 2024 |
| J.B. Puli Ltd | Professional & scientific | 2019 |
| J.Go Training Limited | Professional & scientific | 2001 |
| J2S Services Limited | Administrative & support | 2019 |
| JA Windows & Double Glazing Ltd | Construction | 2024 |
| Jaail Dynamics Ltd | Professional & scientific | 2012 |
| Jabesi Services Limited | Construction | 2014 |
| Jabs Transport Ltd | Transport & logistics | 2018 |
| Jacks Smart Repairs Limited | Wholesale & retail | 2026 |
| Jacky Walker Limited | Health & social care | 2006 |
| Jacob Healthcare Limited | Health & social care | 2013 |
| Jadecote Limited | Extraterritorial | 2025 |
| Jadoon Traders Ltd | Wholesale & retail | 2026 |
| Jaefelectronics Ltd | Wholesale & retail | 2021 |