| Inshfa Limited | Wholesale & retail | 2025 |
| Inside Luxury Travel Limited | Information & communication | 2004 |
| Integro Exercise & Lifestyle Limited | Other services | 2003 |
| Intelligent Prediction Limited | Information & communication | 2014 |
| Intensive Car Unit Limited | Wholesale & retail | 2000 |
| Interactive Media Ltd | Information & communication | 2022 |
| Interior Furnishing Solutions Ltd | Manufacturing | 2025 |
| Intermediary Asset Advisors Limited | Financial services | 2011 |
| International Environmental Solution Limited | Wholesale & retail | 2024 |
| Intertax Recruitment Ltd | Administrative & support | 2024 |
| Inverness Autos Ltd | Wholesale & retail | 2024 |
| Invictus Mind Coaching Ltd | Other services | 2024 |
| Invirtigo Ltd | Education | 2021 |
| Iquality Solutions Ltd | Professional & scientific | 2017 |
| IR Retail Ltd | Wholesale & retail | 2026 |
| IR Superstore Ltd | Wholesale & retail | 2022 |
| Irifinity Ltd | Wholesale & retail | 2024 |
| Iron Kitchen Limited | Hospitality | 2026 |
| Ironshore Estates Ltd | Real estate | 2025 |
| ISA London Invest Ltd | Real estate | 2016 |
| Ishmeh Ltd | Hospitality | 2020 |
| Ishu & Mishu Properties Ltd | Real estate | 2025 |
| Ivanov Maintenance Limited | Construction | 2019 |
| IVF Cube Limited | Health & social care | 2025 |
| Ivory Bamboo Limited | Hospitality | 2026 |
| IVY Homes and Villas Limited | Real estate | 2025 |
| J N&N Limited | Public administration | 2023 |
| J Noah Media Ltd | Other services | 2021 |
| J TAN Limited | Hospitality | 2008 |
| J&Jfrangue Limited | Health & social care | 2022 |
| J&R Consultancy Ltd | Construction | 2022 |
| JA Tiling Limited | Construction | 2017 |
| Jack Cleaning Services Ltd | Administrative & support | 2023 |
| Jacob Stripp Limited | Information & communication | 2022 |
| Jade Garden Warrington Limited | Hospitality | 2021 |
| Jade Newton Limited | Hospitality | 2026 |
| Jamie Firman Management Limited | Professional & scientific | 2022 |
| Jamieg Consultancy Ltd | Professional & scientific | 2026 |
| Jamuna Westcliff Limited | Hospitality | 2024 |
| Janus Financial Ltd | Professional & scientific | 2018 |
| Jasmine Felix Limited | Hospitality | 2026 |
| Jasmine GAO Express Limited | Hospitality | 2019 |
| Jaya Medical Services Limited | Health & social care | 2013 |
| JB Electrical (Southend) Ltd | Construction | 2020 |
| JB Kiely Builders Ltd | Construction | 2021 |
| Jdandp Scaffolding Ltd | Construction | 2022 |
| JDM Quantity Surveyors Limited | Construction | 2025 |
| Jdmd Consulting Limited | Professional & scientific | 2025 |
| JDT Coaching Limited | Arts & recreation | 2026 |
| Jeca Trading Limited | Hospitality | 2015 |
| Jemmor Development Co Ltd | Real estate | 2025 |
| Jemmor Property Investments Ltd | Real estate | 2023 |
| Jemmor Property Services Ltd | Real estate | 2016 |
| Jerk Meets Jollof Limited | Hospitality | 2025 |
| Jess Hawkins Photographic Ltd | Professional & scientific | 2023 |
| Jezeraf Ltd | Wholesale & retail | 2022 |
| Jezwin Limited | Hospitality | 2014 |
| JFS Trade (UK) Ltd. | Wholesale & retail | 2009 |
| Jithin Photography Ltd | Professional & scientific | 2023 |
| JJ Toys Ltd | Wholesale & retail | 2020 |
| JJS88 Limited | Hospitality | 2019 |
| JKV Team Ltd | Hospitality | 2024 |
| Jlpm Services Ltd | Professional & scientific | 2008 |
| JM Property Services Limited | Real estate | 2007 |
| JMA Clearance Ltd | Construction | 2025 |
| JMS ATS Ltd | Professional & scientific | 2025 |
| JMS Financial Consultancy Ltd | Professional & scientific | 2018 |
| JMT Property Limited | Real estate | 2021 |
| JNM Cuisine Limited | Hospitality | 2017 |
| JO and Bell Ltd | Hospitality | 2026 |
| JO Plismy Limited | Wholesale & retail | 1999 |
| Joellie Limited | Professional & scientific | 2000 |
| Joellie Properties Limited | Real estate | 2020 |
| John Walne Workplace Investigations & Training Ltd | Administrative & support | 2025 |
| John Wilkin (Essex) Limited | Construction | 2015 |
| Johnny's Caribbean HUT Limited | Hospitality | 2013 |
| Johnston Strategic Advisory Ltd | Administrative & support | 2026 |
| Jonathan Rhys Recruitment Limited | Administrative & support | 2018 |
| Jones Jones Design Ltd | Arts & recreation | 2023 |
| Jorizellevillablancarn Ltd | Health & social care | 2024 |
| Jorj Electrical Ltd | Construction | 2014 |
| Joyada Ltd | Wholesale & retail | 2023 |
| Joyking LAU Limited | Hospitality | 2026 |
| JP Brothers Investment Ltd | Real estate | 2023 |
| JP Upholstery Limited | Other services | 2016 |
| JP Weng Limited | Hospitality | 2025 |
| JR Medical Ltd | Health & social care | 2003 |
| JRW Aviation Ltd | Professional & scientific | 2024 |
| JRW Real Estate Ltd | Real estate | 2025 |
| Jrwf Health Ltd | Health & social care | 2025 |
| JSD Firerack Limited | Construction | 2015 |
| Jt&Lb Properties Limited | Construction | 2019 |
| JTD Creations Limited | Information & communication | 2024 |
| JTH Scaffolding Ltd | Construction | 2021 |
| JTS Developments (London) Limited | Other services | 2022 |
| Julie’S Beauties Ltd | Other services | 2025 |
| Jumpstart Sport CIC | Education | 2025 |
| Just Kosher Swhc Limited | Hospitality | 2018 |
| Just Rented Limited | Real estate | 2019 |
| Justdoit Investments Ltd | Real estate | 2019 |