| J Cunha Limited | Wholesale & retail | 2017 |
| J D Staffing Limited | Agriculture & fishing | 2021 |
| J DYE Electrical Engineering Limited | Construction | 2025 |
| J E Cook (Building Contractor) Limited | Construction | 2014 |
| J E Jones Contracting Ltd | Construction | 2025 |
| J Featherstone Builder Ltd | Construction | 2021 |
| J Freeman Building Services Ltd | Construction | 2010 |
| J Heanes Electrical Ltd | Manufacturing | 2017 |
| J Heanes Hire Ltd | Administrative & support | 2025 |
| J Howlett Construction Ltd | Construction | 2018 |
| J Ingram Developments Ltd | Construction | 2016 |
| J J Electrical Solutions Limited | Construction | 2014 |
| J K Carpets and Flooring (Cambs) Ltd | Manufacturing | 2022 |
| J Krumina Limited | Professional & scientific | 2022 |
| J M Properties & Roofing Ltd | Construction | 2024 |
| J M Stanberry Properties Limited | Real estate | 2017 |
| J M Turner Limited | Administrative & support | 2010 |
| J O Sims Employee Benefit Trust Limited | Professional & scientific | 2009 |
| J O Sims Holdings (1896) Limited | Professional & scientific | 2012 |
| J O Sims Holdings Limited | Wholesale & retail | 1954 |
| J R M Projects Ltd | Construction | 2011 |
| J Reeve (Spalding) Limited | Wholesale & retail | 2010 |
| J Silva Transport Ltd | Transport & logistics | 2022 |
| J Sweetlove Engineering Limited | Professional & scientific | 2025 |
| J Taylor Tree Services Ltd | Other services | 2013 |
| J Wand Plumbing & Heating Limited | Construction | 2018 |
| J Ward Electrical Contractor Limited | Construction | 2008 |
| J Worx Engineering Ltd | Professional & scientific | 2025 |
| J&B Logistics Ltd | Transport & logistics | 2021 |
| J&C Paving Ltd | Administrative & support | 2025 |
| J&C Roofing and Landscapes Ltd | Administrative & support | 2026 |
| J&L Property Holdings Limited | Real estate | 2025 |
| J&M Tree Surgery and Landscaping Ltd | Administrative & support | 2025 |
| J&P Services Ltd | Wholesale & retail | 2023 |
| J-Stream Aviation Projects Ltd | Professional & scientific | 2021 |
| J. N. C. a. Limited | Transport & logistics | 2022 |
| J. P. Ford Contractors Limited | Construction | 2017 |
| J. Raven Surveyors Limited | Professional & scientific | 2023 |
| J.A. Watts (Mareham) Limited | Agriculture & fishing | 1987 |
| J.E.Piccaver & Co. (Gedney Marsh) | Agriculture & fishing | 1950 |
| J.E.T. and SON Ltd | Transport & logistics | 2019 |
| J.G.Litherland(Rhubarb) | Agriculture & fishing | 1961 |
| J.H. Grundy (Farms) Limited | Agriculture & fishing | 1954 |
| J.L. Farms Limited | Agriculture & fishing | 1929 |
| J.Mitchell Engineering Limited | Manufacturing | 2016 |
| J.T. Ward Joinery Limited | Manufacturing | 2003 |
| J.T.Peach & SON Limited | Agriculture & fishing | 1960 |
| J.T.White(Sheepmarket)Limited | Real estate | 1945 |
| J.Tigfabrication Ltd | Manufacturing | 2020 |
| Jack Buck (Farms) Limited | Agriculture & fishing | 2010 |
| Jack Buck (Holdings) Limited | Agriculture & fishing | 1959 |
| Jack Drive Ltd | Transport & logistics | 2021 |
| Jack TAR Holidays Limited | Hospitality | 2025 |
| Jacobella Ltd | Financial services | 2024 |
| Jacqualine Ltd | Health & social care | 2024 |
| Jacy Ltd | Transport & logistics | 2018 |
| JAE Systems (East Anglia) Ltd | Professional & scientific | 2026 |
| Jagp Ltd | Wholesale & retail | 2024 |
| Jai's Investments Ltd | Real estate | 2025 |
| Jaka Services Limited | Professional & scientific | 2025 |
| Jakers (Essex) Limited | Wholesale & retail | 2010 |
| Jallop (UK) Ltd | Manufacturing | 2020 |
| James Arkley Equine Dental Services Limited | Professional & scientific | 2016 |
| James Crampton Ltd | Transport & logistics | 2012 |
| James Donoughue Limited | Information & communication | 2016 |
| James E. Gray Limited | Other services | 2025 |
| James Taylor Trading Ltd | Professional & scientific | 2024 |
| James Tomlinson Associates Ltd | Professional & scientific | 2019 |
| Jamie Sandford Limited | Real estate | 2020 |
| Jamie Tupholme Ltd | Education | 2015 |
| Jamie's Carpets (Holbeach) Ltd | Wholesale & retail | 2018 |
| Jamieson Installations Ltd | Construction | 2023 |
| Jams Storage Solutions Limited | Transport & logistics | 2025 |
| Janice Bott Ltd | Administrative & support | 2011 |
| Jankus Ltd | Transport & logistics | 2015 |
| Jarem Services Ltd | Transport & logistics | 2020 |
| Jarex Trans Ltd | Transport & logistics | 2018 |
| Jarjak Trans Ltd | Transport & logistics | 2015 |
| Jaroslaw Transport Ltd | Transport & logistics | 2024 |
| Jason Jackson Ltd | Public administration | 2018 |
| Jason Mark Baxter Ltd | Transport & logistics | 2025 |
| Jason Thorpe Property Services Ltd | Construction | 2023 |
| JAY & GEE Delivery Ltd | Transport & logistics | 2023 |
| JAY M Hall Tiling and Tiles Ltd | Wholesale & retail | 2024 |
| JAY Trading Limited | Professional & scientific | 2006 |
| JB Roofing (Cambs) Ltd | Construction | 2021 |
| JBC Recruitment Ltd | Administrative & support | 2025 |
| JBG Limited | Wholesale & retail | 2023 |
| JBL Logistics Ltd | Transport & logistics | 2021 |
| Jbss Services Ltd | Construction | 2022 |
| Jbss(Lincs) Ltd | Manufacturing | 2021 |
| JC Brickwork & Property Maintenance Ltd | Construction | 2023 |
| JC Electrical (Lincs) Limited | Construction | 2021 |
| JC ELY Limited | Hospitality | 2015 |
| JC Holdings (Lincs) Limited | Financial services | 2024 |
| JC Property Developments (Lincs) Limited | Construction | 2025 |
| JC Roof Care Ltd | Construction | 2025 |
| JCR Entertainment Ltd | Administrative & support | 2023 |
| JD Property Assets Ltd | Real estate | 2022 |
| JDF Services (Lincs) Ltd | Construction | 2024 |