| Jaytronics Limited | Manufacturing | 2025 |
| JB Home Services Limited | Professional & scientific | 2024 |
| JBL Repairs Ltd | Professional & scientific | 2023 |
| JDM Powder Tech Limited | Manufacturing | 2014 |
| Jebco Seismic (UK) Limited | Mining & quarrying | 1991 |
| Jeffbullex Ltd | Administrative & support | 2021 |
| Jemteq Limited | Construction | 2017 |
| Jenner Group Services Ltd | Construction | 2022 |
| Jennie Sheldon PR Ltd | Professional & scientific | 2019 |
| Jerrica Properties Ltd | Real estate | 2019 |
| JFG Fire and Security Ltd | Construction | 2026 |
| JFW Homes Ltd | Construction | 2023 |
| JGF Enterprise Advisory Ltd | Professional & scientific | 2026 |
| JIC Group Inc Limited | Information & communication | 2015 |
| Jiln Ltd | Financial services | 2025 |
| Jimmy a Goodger Ltd | Administrative & support | 2017 |
| JJ Autos Kent Ltd | Wholesale & retail | 2020 |
| JJ Rentals Essex Ltd | Administrative & support | 2024 |
| JJ Rentals Kent Ltd | Administrative & support | 2021 |
| JJ Rentals Sussex Ltd | Administrative & support | 2024 |
| JJJ & a Enterprises Limited | Arts & recreation | 2002 |
| JJL Consultants (Kent) Ltd | Information & communication | 2023 |
| JJO Early Years Limited | Education | 2022 |
| JM Lilley Consultancy Limited | Other services | 2014 |
| JM Technologies Ltd | Administrative & support | 2010 |
| Jmam Ltd | Extraterritorial | 2016 |
| JMC Search and Selection Ltd | Administrative & support | 2019 |
| JNO Property Solutions Ltd | Households | 2025 |
| Jobsub Ltd | Professional & scientific | 2022 |
| Joden Interiors Limited | Construction | 2016 |
| Joe’S Flat Roofing Ltd | Construction | 2025 |
| Johnson & Myatt Property Ltd | Real estate | 2017 |
| Jopp Ltd | Real estate | 2012 |
| Jordan Hamlin Limited | Real estate | 2025 |
| Journeyman Barbers Ltd | Other services | 2024 |
| Joy L Limited | Wholesale & retail | 2016 |
| Jpme Building Contractors Ltd | Construction | 2022 |
| JR Construction Group Ltd | Construction | 2022 |
| JRD Kent Ltd | Professional & scientific | 2018 |
| JSD Consultants Limited | Professional & scientific | 2023 |
| JTC Management Ltd | Professional & scientific | 2015 |
| JTP Building and Landscaping Ltd | Construction | 2022 |
| JTW Plasterwork Limited | Construction | 2026 |
| Jupiterjazzy Limited | Wholesale & retail | 2025 |
| Jurick Engineering Limited | Transport & logistics | 2016 |
| Just Advice Holdings Limited | Financial services | 2019 |
| Just Advice Solutions Limited | Financial services | 2017 |
| Just SOE Inspired by Hair Ltd | Other services | 2022 |
| Justin Hynes Limited | Manufacturing | 2009 |
| JW Pump Services Limited | Construction | 2019 |
| JWP Interim Management Limited | Professional & scientific | 2015 |
| JWS Maintenance Kent Limited | Administrative & support | 2012 |
| K-Tec Racing Limited | Wholesale & retail | 2002 |
| K.D.S. (Kingdom Development Services) Limited | Construction | 2016 |
| K.L. Property Lawyers Limited | Professional & scientific | 2004 |
| K2K Play Ltd | Health & social care | 2023 |
| Kakkanat Limited | Health & social care | 2013 |
| Kalavathy Limited | Transport & logistics | 2025 |
| Kandi Capital Ltd | Real estate | 2019 |
| Karen Walker Mortgage Solutions Limited | Financial services | 2022 |
| KAS Group Limited | Construction | 2015 |
| Katie’S Cleans Ltd | Administrative & support | 2026 |
| KC Adams Ltd | Households | 2024 |
| KC Electrical Contractors Limited | Manufacturing | 2025 |
| KC Electrical Services Limited | Construction | 2018 |
| KDG Brixton Ltd | Hospitality | 2024 |
| KDG Dockside Limited | Hospitality | 2024 |
| KDG E&C Ltd | Hospitality | 2023 |
| KDG Hempstead Ltd | Hospitality | 2023 |
| KDG Peckham Limited | Hospitality | 2024 |
| KEF. Commercial Solutions Limited | Professional & scientific | 2013 |
| Kehosa Reforestation Limited | Agriculture & fishing | 2025 |
| Kelp Blue Biotech UK Ltd | Agriculture & fishing | 2023 |
| Kelp Blue Stipe Limited | Agriculture & fishing | 2020 |
| Kendall Cross Limited | Extraterritorial | 2011 |
| Kendall One Ltd | Administrative & support | 2022 |
| Kenilworth Woodside Conference Centre JV LLP | | 2022 |
| Kent Cctv Limited | Extraterritorial | 2012 |
| Kent Counselling Training Ltd | Education | 2024 |
| Kent Financial Ltd | Financial services | 2024 |
| Kent Hearing Limited | Health & social care | 2016 |
| Kent Home Therapy Ltd | Health & social care | 2024 |
| Kent House Sitting Ltd | Agriculture & fishing | 2025 |
| Kent K9 Training Ltd | Other services | 2018 |
| Kent Marine Contractors Limited | Administrative & support | 2015 |
| Kent Marine Towage Limited | Administrative & support | 2015 |
| Kent Medical Imaging Limited | Health & social care | 1999 |
| Kent Medical Ultrasound Ltd | Public administration | 2024 |
| Kent Metal Roofing Ltd | Construction | 2018 |
| Kent Residential Quality Limited | Professional & scientific | 2026 |
| Kent Valley Flooring Ltd | Construction | 2021 |
| Kent Vehicle Solutions Limited | Administrative & support | 2013 |
| Kent Waste Management LLP | | 2024 |
| Kentfield Homes Ltd | Real estate | 2025 |
| Kentfield Hotels Ltd | Hospitality | 2023 |
| Kentfield Property Group Ltd | Real estate | 2021 |
| Kentish Marketing Ltd | Professional & scientific | 2026 |
| Keresley (Coventry) Management Company Limited | Households | 2024 |
| Ketts & KIN Homes Ltd | Construction | 2021 |
| Kevin Karpets Limited | Wholesale & retail | 1972 |