| J O S Technologies Ltd | Wholesale & retail | 2021 |
| J P Flynn Construction Limited | Construction | 2012 |
| J P Flynn Holding Ltd | Financial services | 2022 |
| J P R Digital Appliances Ltd | Other services | 2008 |
| J Property Services Ltd | Extraterritorial | 2013 |
| J R H Construction Limited | Real estate | 1998 |
| J Ramsden Associates Ltd | Professional & scientific | 2018 |
| J Reiter FIC Limited | Professional & scientific | 2024 |
| J S P Building Services Limited | Construction | 2007 |
| J S Trade Supplies Ltd | Wholesale & retail | 2012 |
| J Skitt & Sons (Holdings) Limited | Administrative & support | 2012 |
| J T E Management Ltd | Professional & scientific | 2021 |
| J Tembani Consultancy Ltd | Health & social care | 2015 |
| J W C Plastering Limited | Construction | 2017 |
| J X L Holdings Ltd | Wholesale & retail | 2024 |
| J&D Ashford Investments Ltd | Real estate | 2023 |
| J&D Estates Management Limited | Real estate | 2026 |
| J&D Project Limited | Construction | 2024 |
| J&D Signs Limited | Manufacturing | 2013 |
| J&H Developments (Kent) Ltd | Construction | 2025 |
| J&J Property Maintenance Ltd | Administrative & support | 2016 |
| J&K Rizk Trading Ltd | Wholesale & retail | 2026 |
| J&L Holding Investment Company Ltd | Financial services | 2015 |
| J&L Painting and Carpentry Ltd | Construction | 2024 |
| J&O Groundworks and Construction Ltd | Construction | 2025 |
| J&P Nest Ltd | Real estate | 2022 |
| J&R Cousins Limited | Professional & scientific | 2013 |
| J&R Marketing Limited | Professional & scientific | 2016 |
| J&T Property Services Limited | Administrative & support | 2014 |
| J. Fuller Builders Limited | Construction | 2002 |
| J. Ganley Carpentry Ltd | Manufacturing | 2020 |
| J. Miller Roofing Limited | Construction | 2021 |
| J. P. Estates (Kent) Limited | Real estate | 1972 |
| J.A.M Marketing & Hospitality Management Ltd | Professional & scientific | 2009 |
| J.Aubuilder Ltd | Construction | 2022 |
| J.D.Rims Ltd | Wholesale & retail | 2016 |
| J.E.K. Plastering Services Limited | Construction | 2015 |
| J.F. Tanner and R.J. Tanner Limited | Water & waste | 2018 |
| J.K. Builders Limited | Construction | 2001 |
| J.O.B. Electrical Contractors Ltd | Construction | 2013 |
| J.R. Ballard Limited | Professional & scientific | 2025 |
| J.R. Farm Meats Limited | Agriculture & fishing | 2000 |
| J.R. Paving Limited | Construction | 2003 |
| J.R.& F.Line Limited | Wholesale & retail | 1963 |
| J.W.Boyd & Sons Limited | Agriculture & fishing | 1961 |
| J1 Tech Limited | Information & communication | 2023 |
| J10 Electrical Services Limited | Construction | 2005 |
| Jaat Service Station Limited | Wholesale & retail | 2021 |
| JAC Rope Access Ltd | Construction | 2014 |
| Jachi Health Ltd | Health & social care | 2025 |
| Jack Attwood Hair Ltd | Other services | 2020 |
| Jack Fullers Traditional Fish and Chips Ltd | Hospitality | 2024 |
| Jack Kerr Electrical Services Ltd | Construction | 2022 |
| Jack Kilpatrick Hairdressing Ltd | Administrative & support | 2014 |
| Jack Matthews Limited | Wholesale & retail | 2012 |
| Jack Omalley Ltd | Construction | 2023 |
| Jacks Barn Ltd | Hospitality | 2021 |
| Jackson & Power Controls Ltd | Administrative & support | 2023 |
| Jacob & Martin Ltd | Health & social care | 2015 |
| Jacquetta Levon Ltd | Other services | 2022 |
| Jadecrea Limited | Construction | 1986 |
| Jadt Enterprise Limited | Real estate | 2021 |
| Jager Building and Management Services Ltd | Real estate | 2018 |
| Jager Electrical Contractors Ltd | Construction | 2011 |
| Jager Integration Limited | Information & communication | 2025 |
| Jager Property Developments Ltd | Construction | 2020 |
| JAI Durga MAA Ltd | Hospitality | 2019 |
| Jaipur Homes Ltd | Real estate | 2021 |
| JAK63 Limited | Administrative & support | 2018 |
| Jakes Property Limited | Households | 2024 |
| Jakidom Global Ltd | Information & communication | 2023 |
| Jakob James Designer Homes Limited | Financial services | 2021 |
| Jamax Limited | Real estate | 2023 |
| Jambhala Ltd | Real estate | 2022 |
| James & Kither,Limited | Financial services | 1933 |
| James Auctioneers Limited | Administrative & support | 2012 |
| James Auctioneers Properties Limited | Financial services | 2025 |
| James Baxter Media Limited | Professional & scientific | 2009 |
| James EVE Accountancy Limited | Professional & scientific | 2013 |
| James Frank Associates Ltd | Administrative & support | 2017 |
| James Harvard Homes Ltd | Real estate | 2018 |
| James Holledge Design Ltd | Information & communication | 2014 |
| James Lambeth Limited | Administrative & support | 2015 |
| James Larkin Landscapes Ltd | Administrative & support | 2015 |
| James Laslett Consulting Limited | Administrative & support | 2012 |
| James Longstaff Limited | Manufacturing | 2023 |
| James M Bruce Ltd | Construction | 2019 |
| James Read Beauty Limited | Wholesale & retail | 2018 |
| James Read Glow Ltd | Other services | 2023 |
| James Wilkinson Painter & Decorator Building & Maintenance Limited | Other services | 2017 |
| Jamie Brown Construction Ltd | Construction | 2022 |
| Jamie Powell Ltd | Information & communication | 2015 |
| Jamieson Heating Services Ltd | Construction | 2025 |
| Jamie’S Driving School Ashford Kent Limited | Education | 2026 |
| Jamil Afzaal Ltd | Wholesale & retail | 2025 |
| Jampact Recordings Limited | Professional & scientific | 2013 |
| JAN & Jehan Medical Services Limited | Health & social care | 2013 |
| Jane Karen Associates Limited | Administrative & support | 2006 |
| Jane V Hales Limited | Professional & scientific | 2017 |
| Janik Distribution Limited | Wholesale & retail | 2020 |