| IN2 Diving Ltd | Education | 2020 |
| Inca Partners LLP | | 2021 |
| Incredible Edible Gosport CIC | Other services | 2023 |
| Incrowd Safety Ltd | Professional & scientific | 2023 |
| Indalo Transport Ltd | Transport & logistics | 2021 |
| Indalo UK Investments Ltd | Real estate | 2025 |
| Indepenergy Ltd | Professional & scientific | 2025 |
| Indolanka Restaurant Ltd | Hospitality | 2021 |
| Industrial Pipe Systems Limited | Construction | 2005 |
| Industrial Roofing Services Limited | Construction | 2006 |
| Infinity Digital International Ltd | Information & communication | 2018 |
| Info Layer Limited | Information & communication | 2014 |
| Inkpen Property Services Ltd | Manufacturing | 2025 |
| Inkwell Accountancy Limited | Professional & scientific | 2025 |
| Innovation Hair, Beauty & Hair Loss Clinic Ltd | Other services | 2019 |
| Insulation Exchange Ltd | Construction | 2026 |
| Intelligence Finance Solutions Ltd | Financial services | 2013 |
| International Neuro-Linguistic Programming Trainers Association Limited | Other services | 1995 |
| Inverra Consulting Group Ltd | Professional & scientific | 2025 |
| IOW Limited | Professional & scientific | 2021 |
| IOW Pharma Ltd | Wholesale & retail | 2025 |
| Iris Innovations Limited | Manufacturing | 2005 |
| Iron Heart International Ltd | Wholesale & retail | 2014 |
| Itchen Technologies Limited | Information & communication | 2023 |
| Itsjustus Ltd | Professional & scientific | 2024 |
| It’S a Property Company Ltd | Real estate | 2019 |
| It’S Raining Art Ltd | Extraterritorial | 2021 |
| Ivel Valley Ltd | Wholesale & retail | 2026 |
| J & B Precision Services Limited | Professional & scientific | 2004 |
| J & D Flooring Ltd | Extraterritorial | 2013 |
| J & J Events (South Coast ) Limited | Administrative & support | 2026 |
| J & SON Electrical Ltd | Construction | 2015 |
| J a Holdings South Coast Limited | Real estate | 2024 |
| J Bell Offshore Limited | Professional & scientific | 2015 |
| J Malyon Electrical Services Ltd | Construction | 2018 |
| J Phang Services & Investments Limited | Information & communication | 2024 |
| J Stock Building & Property Maintenance Ltd | Construction | 2013 |
| J Wilkinson & Cook Building and Roofing Limited | Construction | 2020 |
| J&V Ecommerce Ltd | Wholesale & retail | 2025 |
| J&W Pearman Limited | Administrative & support | 2022 |
| J.Lower Cornwell Limited | Real estate | 2023 |
| J.O. Global Ventures Limited | Administrative & support | 2014 |
| Jain Property Limited | Real estate | 2020 |
| Jamaica Place Limited | Hospitality | 2023 |
| Jamax Support Services Limited | Extraterritorial | 2025 |
| James Law Author Ltd | Professional & scientific | 2013 |
| James Stott Projects Ltd | Professional & scientific | 2018 |
| Jamesmark Ltd | Administrative & support | 2008 |
| Jamesmark Property Limited | Real estate | 2017 |
| Jamesurl Limited | Professional & scientific | 2015 |
| Jamie Wellington Carpentry Ltd | Construction | 2018 |
| Jamtopia Limited | Other services | 2018 |
| Jamuna Enterprises Ltd | Real estate | 2026 |
| Jarr Estates Ltd | Real estate | 2025 |
| Jaskolski Property Ltd | Real estate | 2022 |
| Jasonbrant Limited | Manufacturing | 2019 |
| JB Scaffold Ltd | Construction | 2021 |
| JBO Services Limited | Professional & scientific | 2016 |
| JBS Civils Limited | Construction | 2018 |
| JBW Accountancy Ltd | Professional & scientific | 2024 |
| JCL Marine Services Limited | Professional & scientific | 2014 |
| JD Carpentry Ltd | Construction | 2012 |
| JDL Engineering Limited | Manufacturing | 2018 |
| Jegam Cleans Limited | Administrative & support | 2025 |
| Jema Utilities Ltd | Construction | 2022 |
| Jess Owens Garden Services Limited | Other services | 2007 |
| Jetmile Holdings Limited | Real estate | 2017 |
| Jetmile Ventures Limited | Administrative & support | 2016 |
| JF Football Coaching Ltd | Arts & recreation | 2025 |
| Jfcs Refrigeration Ltd | Construction | 2026 |
| JHC Carpentry Limited | Construction | 2010 |
| JHC Services Ltd | Professional & scientific | 2020 |
| JIM Gant Associates Ltd | Professional & scientific | 2007 |
| JJ JO Industry Limited | Health & social care | 2017 |
| JJ2 Investments Limited | Transport & logistics | 2019 |
| JJC Construction Ltd | Construction | 2021 |
| JJI Properties Ltd | Real estate | 2024 |
| JJS Engineering Ltd | Wholesale & retail | 2023 |
| JJS UK Holdings Ltd | Financial services | 2025 |
| Jlaty Property Ltd | Real estate | 2006 |
| JLH Property Hampshire Ltd | Real estate | 2025 |
| JM Cleaning Solutions Ltd | Administrative & support | 2018 |
| JMJ (Locks Heath) Limited | Transport & logistics | 2015 |
| Jmlc Assets LLP | | 2025 |
| Jmlc Properties Limited | Households | 2024 |
| JMR Wall Coatings Limited | Construction | 2025 |
| Johnnie Lewis Plastering Ltd | Construction | 2019 |
| Joint Properties South Coast Limited | Administrative & support | 2006 |
| JON Tyrrell Studio Ltd | Professional & scientific | 2022 |
| Jordan Homes Limited | Construction | 1999 |
| JOS Health Care Ltd | Health & social care | 2017 |
| Joseph Howard Ltd | Real estate | 2003 |
| JPG Management Services Limited | Professional & scientific | 2015 |
| JR Spraying Services Ltd | Construction | 2025 |
| JR Sterling Properties Limited | Real estate | 2026 |
| JRC Access UK Ltd | Construction | 2021 |
| JRC Catering Ltd | Hospitality | 2020 |
| JRC Commercial Concrete Ltd | Manufacturing | 2022 |
| JRC Commercial Ltd | Real estate | 2020 |
| JRC Facilities Ltd | Construction | 2003 |