| IZ Certi Music Ltd | Information & communication | 2023 |
| Izrproperties Ltd | Administrative & support | 2024 |
| J & J Bulk Services Ltd | Transport & logistics | 2020 |
| J & J Services (Kent) Ltd | Transport & logistics | 2015 |
| J & M Electrical Kent Ltd | Construction | 2019 |
| J & S Plumbing & Heating Centre Limited | Construction | 2010 |
| J and T Food and Beverages Limited | Hospitality | 2025 |
| J Brown Plant Limited | Construction | 2024 |
| J C C Plumbing Services Ltd | Construction | 2024 |
| J E R Carpentry Limited | Construction | 2022 |
| J G Palmer LLP | | 2003 |
| J Horne Builders Limited | Construction | 2012 |
| J J and B Treecare Limited | Agriculture & fishing | 2008 |
| J J Interiors (Kent) Ltd | Construction | 2023 |
| J J Multi Services Ltd | Professional & scientific | 2018 |
| J L H Drains Limited | Other services | 2014 |
| J Menditta Fire Protection Ltd | Construction | 2006 |
| J P Dwellings Ltd | Real estate | 2018 |
| J Peckham Limited | Construction | 2026 |
| J PYM Finance Ltd | Financial services | 2016 |
| J R Priest Limited | Construction | 2025 |
| J S Knott Legal Services Limited | Administrative & support | 2013 |
| J Squared Developments Limited | Construction | 2019 |
| J Stammers Building Services Limited | Construction | 2025 |
| J Starc Limited | Construction | 2019 |
| J Stewart Plumbing Ltd | Construction | 2024 |
| J W Benning Farrier Ltd | Agriculture & fishing | 2020 |
| J W H Plumbing & Heating Limited | Construction | 2015 |
| J Willers Limited | Information & communication | 2012 |
| J&Db Carpets Ltd | Wholesale & retail | 2021 |
| J&J Ace Properties Ltd | Real estate | 2022 |
| J&J Distributors Ltd | Wholesale & retail | 2026 |
| J&M Castles Hire Ltd | Administrative & support | 2026 |
| J&M Property Investments Limited | Hospitality | 2019 |
| J&T Development Projects Ltd | Construction | 2026 |
| J&V Properties Management Limited | Real estate | 2024 |
| J. & D. Mackintosh (Investments) Limited | Real estate | 1973 |
| J. B. Industrial Doors Limited | Wholesale & retail | 1986 |
| J. Byrne Plant Hire & Civil Engineering Limited | Construction | 1980 |
| J.Barker Maintenance Limited | Administrative & support | 2014 |
| J.E.S. Arnold (Domestic Appliances) Limited | Real estate | 1966 |
| J.P Contract Services Limited | Administrative & support | 2017 |
| J.Rudd Groundworks and Developments Ltd | Construction | 2020 |
| J.V. Transport Logistics Ltd | Transport & logistics | 2020 |
| J7TRADING Ltd | Wholesale & retail | 2026 |
| JA Consultancy (UK) Ltd | Professional & scientific | 2008 |
| Jack Adjusting Limited | Professional & scientific | 2017 |
| Jack Improvement Limited | Construction | 2019 |
| Jackie Gammage Property Investments Ltd | Real estate | 2020 |
| Jackson Group Development Ltd | Construction | 2023 |
| Jackson Group Holdings Ltd | Financial services | 2023 |
| Jackson Group Investments (Coolhurst) Ltd | Construction | 2024 |
| Jackson Group Investments Ltd | Financial services | 2023 |
| Jacksons Flooring Limited | Construction | 2026 |
| Jacksons Hub Limited | Other services | 2020 |
| Jacob and Thomas Property Management Services Limited | Real estate | 2025 |
| Jadp Carpentry Limited | Manufacturing | 2024 |
| JAG Reward Solutions Limited | Administrative & support | 2008 |
| JAK Consulting Ltd | Administrative & support | 2018 |
| Jake Faktor Consultancy Ltd | Administrative & support | 2019 |
| Jakof Medical Ltd | Health & social care | 2022 |
| JAL Legal Services Limited | Professional & scientific | 2025 |
| Jalys Concept Ltd | Health & social care | 2022 |
| Jama Consultants Ltd | Professional & scientific | 2016 |
| James Baylay Limited | Arts & recreation | 2007 |
| James Ledger Estates Limited | Agriculture & fishing | 1997 |
| James Nazir Limited | Professional & scientific | 2016 |
| Jan's Business Enterprise Limited | Wholesale & retail | 2018 |
| Janson Property Holdings Limited | Real estate | 2026 |
| JAO PMO Consultancy Ltd | Professional & scientific | 2025 |
| JAR Training Consultancy Ltd | Administrative & support | 2015 |
| Jarva Projects Ltd | Administrative & support | 2025 |
| Jascom Electrical Contractors Limited | Construction | 2001 |
| Jascom Electrical Mechanical Limited | Construction | 2020 |
| Jasmine Kent Ltd | Hospitality | 2022 |
| Jast Transport Ltd | Transport & logistics | 2019 |
| Jay's Controls, Instrumentation & Electrical Engineering Services Ltd. | Professional & scientific | 2017 |
| Jaycee Resource Ltd | Administrative & support | 2019 |
| Jays Autos Limited | Administrative & support | 2009 |
| Jays Suites Management Ltd | Real estate | 2025 |
| Jayzee HR Systems Services Limited | Administrative & support | 2026 |
| Jazr Ltd | Real estate | 2024 |
| JB Construction Plant Academy Limited | Administrative & support | 2020 |
| JB Custom Carpentry Ltd | Construction | 2024 |
| JB Elite Consulting Limited | Professional & scientific | 2024 |
| JB Project Management Services Limited | Construction | 2019 |
| JB Training Enterprises Ltd | Education | 2011 |
| JBC Flooring Limited | Construction | 2009 |
| Jbgm Properties Ltd | Real estate | 2024 |
| JBK & Sons Limited | Real estate | 2026 |
| JBK Product Solutions Ltd | Wholesale & retail | 2018 |
| JBK Property Solutions Ltd | Real estate | 2020 |
| JBN Properties Ltd | Real estate | 2024 |
| Jbyways Ltd | Real estate | 2020 |
| JC Offshore Ltd | Construction | 2016 |
| JC Property Investment & Maintenance Ltd | Construction | 2025 |
| JCB Management Ltd | Professional & scientific | 2018 |
| Jcbc Building & Construction Ltd | Construction | 2025 |
| JCC BMS Panel Solutions Limited | Manufacturing | 2026 |
| JCE Surveying Limited | Administrative & support | 2013 |