| J Dowle Fencing & Garden Services Ltd | Administrative & support | 2007 |
| J Edwards Holdings Ltd | Financial services | 2021 |
| J H Taylor Limited | Real estate | 2016 |
| J Harmsworth Limited | Professional & scientific | 2020 |
| J Hewett Electrical Ltd | Construction | 2025 |
| J Jarvinen Ltd | Professional & scientific | 2023 |
| J K Construction (South East) Limited | Construction | 2016 |
| J K Homes (South East) Limited | Construction | 2025 |
| J K Residential (Kent) Ltd | Construction | 2025 |
| J M Carpentry (Kent) Ltd | Construction | 2009 |
| J M D Heating & Plumbing Limited | Construction | 2001 |
| J Mannell Air Conditioning Ltd | Construction | 2011 |
| J Mcleish Consultancy Limited | Professional & scientific | 2024 |
| J Noble Lettings Ltd | Real estate | 2017 |
| J P Stern Ltd | Agriculture & fishing | 2013 |
| J Park Plant Hire Limited | Administrative & support | 2015 |
| J Pearce Embalming Service Ltd | Other services | 2012 |
| J R Southern Limited | Construction | 2015 |
| J Sabai Spa Limited | Other services | 2016 |
| J T Industrial Door Holdings Limited | Other services | 2011 |
| J V Solutions Limited | Administrative & support | 2000 |
| J&A Relwani Ltd | Health & social care | 2016 |
| J&D Recovery Limited | Transport & logistics | 2024 |
| J&E Services Limited | Wholesale & retail | 2025 |
| J&H Security Services Ltd | Construction | 2025 |
| J&L Decorators Ltd | Construction | 2016 |
| J'Silva Deli Ltd | Hospitality | 2025 |
| J. W. Meek Laboratories Limited | Health & social care | 2001 |
| J.B. Sign (Productions) Limited | Administrative & support | 1998 |
| J.D. Bush Decorators Limited | Construction | 2006 |
| J.D. Fire Services Limited | Energy | 2009 |
| J.H. & R.R. Mundy (Roofing Supplies) Limited | Construction | 1977 |
| J.I.K. Software Limited | Administrative & support | 2004 |
| J.M.W. Architectural Aluminium Ltd | Construction | 2010 |
| J.Makepeace Surfacing Ltd | Construction | 2023 |
| J.Toms Limited | Wholesale & retail | 1961 |
| J.W. Frith Ltd. | Agriculture & fishing | 1983 |
| JAA Services Ltd | Administrative & support | 2023 |
| Jacal Construction Equipment & Plant Hire Limited | Administrative & support | 1997 |
| Jacaranda Property Limited | Real estate | 2022 |
| Jacaranda Windows Limited | Real estate | 1992 |
| Jacash Limited | Wholesale & retail | 1987 |
| Jack J Bonner Developments Ltd | Construction | 2022 |
| Jack J Bonner Holdings Ltd | Real estate | 2022 |
| Jack Midson Coaching Ltd | Education | 2020 |
| Jack's Cosy Campers Ltd | Administrative & support | 2023 |
| Jacko Properties Limited | Real estate | 2025 |
| Jackson Crane Limited | Administrative & support | 1997 |
| Jacob Niblett Ltd | Information & communication | 2014 |
| Jacqueline Fearon Ltd | Health & social care | 2016 |
| JAD Trans Limited | Transport & logistics | 2012 |
| JAF Design Ltd | Professional & scientific | 2007 |
| Jagdmatch Limited | Professional & scientific | 2020 |
| Jags Property Services Limited | Real estate | 2017 |
| JAM on Burnt Toast Ltd | Administrative & support | 2023 |
| Jambino Ltd | Manufacturing | 2019 |
| Jamcem Consulting Ltd | Professional & scientific | 2011 |
| Jameco Construction CFO Limited | Professional & scientific | 2026 |
| Jameco Group Holdings Limited | Financial services | 2022 |
| Jameco Group Limited | Professional & scientific | 2022 |
| Jameco Practice Advisory Limited | Professional & scientific | 2026 |
| Jamed Properties Limited | Real estate | 2020 |
| James and Presh Asmr Eating Limited | Information & communication | 2024 |
| James Bignell Photography Limited | Professional & scientific | 2005 |
| James Brickworks Limited | Construction | 2021 |
| James Davis Catering Limited | Hospitality | 2013 |
| James Educational Consulting Limited | Education | 2016 |
| James Friend Limited | Information & communication | 2015 |
| James Hunt (Maidstone) Limited | Water & waste | 1964 |
| James North Photography Limited | Professional & scientific | 2024 |
| James Padwick Audio Limited | Professional & scientific | 2021 |
| James Seal and SON Limited | Construction | 2006 |
| James Surgical Limited | Health & social care | 2019 |
| Jamie Shiels CGI Ltd | Information & communication | 2011 |
| JAN Taranczuk Associates Limited | Professional & scientific | 2009 |
| Jandkbuildingserviceskent Ltd | Construction | 2021 |
| Janet Hill Coaching Ltd | Education | 2012 |
| Jannat Spice Rugby Ltd | Hospitality | 2023 |
| Japanese Guru Ltd | Wholesale & retail | 2021 |
| Jarvis Heating (Kent) Limited | Construction | 2016 |
| JAS Future Limited | Administrative & support | 2010 |
| Jasmin's Tea Room Ltd | Hospitality | 2025 |
| Jasmine Care (South East) Limited | Administrative & support | 2013 |
| Jasmine Court Residents Management Company Limited | Households | 2006 |
| Jason Smith Limited | Transport & logistics | 2025 |
| Jason-Peter Smith Limited | Extraterritorial | 2025 |
| Jastecha Ltd | Real estate | 2020 |
| Javae Property Ltd | Real estate | 2024 |
| Jaxco Limited | Professional & scientific | 2019 |
| Jayan Care Homes Ltd | Health & social care | 2022 |
| Jayan Limited | Real estate | 2016 |
| Jayan Property Limited | Real estate | 2020 |
| Jayanti Kacho Soon Wholesale Ltd | Wholesale & retail | 2023 |
| Jayne Kilgallen Interim Solutions Limited | Health & social care | 2010 |
| Jayne Peirce Holdings Limited | Extraterritorial | 2014 |
| Jayne Peirce Recruitment Solutions Limited | Administrative & support | 2011 |
| Jazminka Ltd | Wholesale & retail | 2023 |
| Jazzit Limited | Information & communication | 2008 |
| JB Critchell Management Services Limited Ltd. | Construction | 2025 |
| JB Sofa's Limited | Wholesale & retail | 2026 |