| Jeans Jackets Ltd | Hospitality | 2025 |
| Jedon Ltd | Professional & scientific | 2020 |
| JEH Buzzing Limited | Professional & scientific | 2014 |
| Jeladesh Limited | Information & communication | 2015 |
| Jellis Educational Tours Limited | Education | 2016 |
| Jellis Properties and Investment Limited | Real estate | 2025 |
| Jellis Seafoods Limited | Wholesale & retail | 2020 |
| Jelo Cyber Security Services Limited | Administrative & support | 2022 |
| Jenkins Facilities and Property Management Limited | Administrative & support | 2023 |
| Jeremy a Property Ltd | Real estate | 2026 |
| Jessy J'S Ecoclean Ltd. | Extraterritorial | 2023 |
| Jesus Family Chapel | Other services | 2009 |
| Jesus the Way, the Truth and the Life Ministries, London (AKA Divine Connection Church) | Other services | 2013 |
| Jetstream Tours Ltd | Transport & logistics | 2013 |
| JF Financial Consultant Ltd | Professional & scientific | 2026 |
| Jfdd Limited | Health & social care | 2022 |
| JFF Limited | Construction | 2022 |
| Jigsaw Paving Limited | Construction | 2007 |
| JIM Henley Consulting Ltd | Professional & scientific | 2019 |
| Jireh Paramount Services UK Limited | Health & social care | 2017 |
| JJ Landscapes of Rainham Kent Limited | Administrative & support | 2023 |
| JK Abbey Ltd | Construction | 2019 |
| JLW Accommodations Ltd | Real estate | 2023 |
| JLW Property Sourcing Ltd | Real estate | 2023 |
| JM Business Group Ltd | Wholesale & retail | 2022 |
| JM Property Rentals (Kent) Limited | Real estate | 2019 |
| JM Quality Control Ltd | Hospitality | 2025 |
| JMA Consultants Ltd | Professional & scientific | 2023 |
| Jmart Bookings Limited | Administrative & support | 2024 |
| Jmart Cares Limited | Health & social care | 2024 |
| Jmart Properties Limited | Real estate | 2023 |
| JME Services Limited | Construction | 2021 |
| JMH Electrical Supplies Ltd | Wholesale & retail | 2024 |
| JMH Scaffolding Limited | Construction | 2024 |
| Jmpower Ltd | Professional & scientific | 2019 |
| JMS Mortgage Solutions Ltd | Financial services | 2024 |
| JMS Property Holdings Limited | Real estate | 2020 |
| JO and Sons Company Ltd | Wholesale & retail | 2016 |
| Jo-Eleanors Bread and Butter Teynham Ltd | Hospitality | 2024 |
| Jo-Glory Limited | Real estate | 2020 |
| Jobflow Ltd | Administrative & support | 2025 |
| Jobraine Limited | Health & social care | 2023 |
| Jofa Nicole Enterprises Limited | Hospitality | 2021 |
| John Beak Limited | Information & communication | 2023 |
| John Dean Plumbing and Heating Ltd | Construction | 2019 |
| Johnbabs Services Ltd | Administrative & support | 2019 |
| Johnson RAY Limited | Wholesale & retail | 2006 |
| Johvick Solutions Limited | Construction | 2026 |
| Joinsky Property Management Limited | Real estate | 1990 |
| Jokoson Limited | Transport & logistics | 2018 |
| Jones Heating Solutions Ltd | Construction | 2019 |
| Josh & Joel Limited | Health & social care | 2015 |
| Josmec Limited | Information & communication | 2025 |
| Journey Bookkeeping and Accounts Limited | Professional & scientific | 2023 |
| Journeytech Consultancy Limited | Information & communication | 2024 |
| Jovita Visions Ltd | Health & social care | 2016 |
| Joy Nails Limited | Other services | 2023 |
| Joysprings Ltd | Administrative & support | 2016 |
| JP Elite Services Ltd | Administrative & support | 2026 |
| JP Farming Services Limited | Agriculture & fishing | 2018 |
| Jpcf Commercial Consulting Ltd | Professional & scientific | 2025 |
| JPD Cleaning Services Ltd | Administrative & support | 2011 |
| JPJ Dynamics Group Limited | Professional & scientific | 2018 |
| JPJ Dynamics Ltd | Financial services | 2015 |
| JPM GAS Ltd | Construction | 2018 |
| JPP Pharma Limited | Wholesale & retail | 2024 |
| JRD Automotive Ltd | Wholesale & retail | 2022 |
| JRD Supreme Limited | Health & social care | 2023 |
| JRJ Group Ltd | Financial services | 2021 |
| JRW Building Services Limited | Construction | 2017 |
| JSS Carpentry & Building Services Ltd | Construction | 2020 |
| JSS Mentoring Limited | Administrative & support | 2023 |
| JST Medical Limited | Health & social care | 2025 |
| JSW Scientific Limited | Professional & scientific | 2020 |
| JTW Assets Limited | Financial services | 2021 |
| JTW Commercial Fleet Rentals Limited | Administrative & support | 2025 |
| Juhey Healthcare Limited | Health & social care | 2014 |
| Jukinebo Limited | Information & communication | 2016 |
| Julia Brendel Limited | Manufacturing | 2012 |
| Julian Austin Photography Ltd | Professional & scientific | 2020 |
| Julian's PIE and Mash Ltd | Hospitality | 2025 |
| Jurveg Property Ltd | Real estate | 2024 |
| Jury Contracts Limited | Construction | 2009 |
| Justern Logistics Ltd | Transport & logistics | 2024 |
| Justye Limited | Health & social care | 2018 |
| JWR Property Limited | Real estate | 2019 |
| JWR Wealth Limited | Financial services | 2019 |
| K & L Investments Limited | Real estate | 2020 |
| K & M J Attwood Limited | Agriculture & fishing | 2011 |
| K & R Lorton Properties Limited | Real estate | 2023 |
| K & T Fehmi Limited | Real estate | 2011 |
| K N R Car Sales Ltd | Wholesale & retail | 2025 |
| K. Furey CBT Ltd | Health & social care | 2014 |
| K.E.W.S. Homes Ltd | Construction | 2005 |
| K.F. Drilling Limited | Construction | 2003 |
| K2 Heating Ltd | Construction | 2022 |
| K9 Connections South East Ltd | Administrative & support | 2016 |
| KA Hair Ltd | Other services | 2022 |
| KA Retail Solutions Ltd | Wholesale & retail | 2026 |
| KAD Photography Limited | Professional & scientific | 2015 |