| James Green Construction Limited | Construction | 2016 |
| James M Scaffolding Ltd | Construction | 2025 |
| James Oakes Ltd | Professional & scientific | 2016 |
| James Properties (Norfolk) Limited | Real estate | 2014 |
| Jamie Butcher TM Ltd | Construction | 2023 |
| Jamie Rodgers Crafts Ltd | Arts & recreation | 2024 |
| Jane Richards Interiors Limited | Wholesale & retail | 2005 |
| Jarvis GAS Heating and Engineering (EA) Limited | Construction | 2020 |
| Jasmine Housing Ltd | Real estate | 2019 |
| Jason Donaldson Limited | Construction | 2003 |
| Jatacom Limited | Health & social care | 2009 |
| JAW Electrical Contractors Limited | Construction | 2020 |
| JAX Carpentry Services Limited | Construction | 2013 |
| JAX Holdco Limited | Financial services | 2024 |
| JAX Investment Property Limited | Real estate | 2024 |
| JAX Plumbing and Heating Limited | Construction | 2020 |
| Jaykay Property Limited | Real estate | 2018 |
| Jaymes Brown Holdings Limited | Real estate | 2023 |
| Jays Bike N Trike Limited | Wholesale & retail | 2015 |
| Jaza International Ltd | Wholesale & retail | 2026 |
| JB & RE Developments Ltd | Real estate | 2023 |
| JB Boxing Ltd | Arts & recreation | 2023 |
| JB Fabrication Services Ltd | Construction | 2019 |
| JB Global Ltd | Construction | 2024 |
| Jbds Property Limited | Real estate | 2022 |
| JC Container Storage Limited | Extraterritorial | 2017 |
| JC Plumbing & Heating East Anglia Ltd | Construction | 2021 |
| Jc&A Limited | Professional & scientific | 2025 |
| JCB Developments (East Anglia) Limited | Construction | 2013 |
| Jcm&E Ltd | Manufacturing | 2023 |
| JCS Aviation Services Ltd | Professional & scientific | 2026 |
| JCS Vehicle Sales Ltd | Wholesale & retail | 2022 |
| JD Dentistry Limited | Health & social care | 2023 |
| JD Security and Fire Ltd | Administrative & support | 2020 |
| JDC Developers Limited | Construction | 2016 |
| JDS Distribution Ltd | Wholesale & retail | 2022 |
| Jeckells of Wroxham Limited | Administrative & support | 1998 |
| JED Property Management Ltd | Real estate | 2025 |
| JED Roberts Electrical Services Ltd | Construction | 2025 |
| JEM Properties Limited | Real estate | 2023 |
| Jenama Properties Limited | Real estate | 2022 |
| Jenex Limited | Mining & quarrying | 1996 |
| Jerez Holdings Ltd | Financial services | 2022 |
| Jessree Catering (Potter Heigham) Limited | Hospitality | 2016 |
| Jessup Osteopath Clinic Ltd | Health & social care | 2019 |
| Jeswick Ltd | Administrative & support | 2018 |
| Jett Holdings Ltd | Transport & logistics | 2019 |
| Jett Trade Limited | Transport & logistics | 2012 |
| JFX Properties Ltd | Real estate | 2026 |
| JG PPS Ltd | Administrative & support | 2014 |
| JH Cable Limited | Mining & quarrying | 2023 |
| JH Marketing Ltd | Information & communication | 2017 |
| Jiffy Tech Limited | Information & communication | 2025 |
| JLA Surveys Limited | Professional & scientific | 2016 |
| Jlcsea Ltd | Hospitality | 2016 |
| Jlms Ventures Limited | Hospitality | 2021 |
| JM Holmes Electrical Ltd | Construction | 2025 |
| JMB Builder (Fleggburgh) Limited | Construction | 2021 |
| JME Property Ltd | Real estate | 2001 |
| JMG Plant Ltd | Construction | 2018 |
| Jmtax&Accountancy Services Ltd | Professional & scientific | 2021 |
| JMW Event Productions Ltd | Hospitality | 2024 |
| JN Home Interiors Ltd | Wholesale & retail | 2021 |
| Joes Chippy Limited | Hospitality | 2024 |
| John H Simpson (Payroll) Limited | Administrative & support | 2011 |
| Joinideal Property Management Limited | Households | 1989 |
| Jojolintus Ltd | Health & social care | 2016 |
| Jomet & Sheeja Homes Limited | Real estate | 2023 |
| Jonas Offshore Ltd | Professional & scientific | 2019 |
| Jones Access Ltd | Professional & scientific | 2022 |
| Jones Family Bakeries Ltd | Hospitality | 2023 |
| Jontrident Limited | Administrative & support | 2011 |
| Jordan & Co Lawyers UK Limited | Professional & scientific | 2020 |
| JP Fit Ltd | Arts & recreation | 2018 |
| JP Welding & Fabrication Limited | Construction | 2024 |
| JPB Solutions Ltd | Hospitality | 2023 |
| JPH Energy Limited | Mining & quarrying | 2023 |
| JPJ Pharmaceuticals Ltd | Wholesale & retail | 2023 |
| JPS Fixing Ltd | Administrative & support | 2013 |
| JPW and Sons Electrical Engineering Limited | Manufacturing | 2016 |
| JR Hull Law Ltd | Professional & scientific | 2021 |
| JR Products Ltd | Manufacturing | 2014 |
| Jrsh Onshore Ltd | Mining & quarrying | 2024 |
| JRT Caravans Limited | Other services | 2002 |
| JS Music Services Limited | Arts & recreation | 2003 |
| JSA Simon Ltd | Hospitality | 2026 |
| JSC Holdings (East Anglia) Ltd | Administrative & support | 2017 |
| Jshi Ltd | Construction | 2022 |
| JSP Real Estate Ltd | Real estate | 2023 |
| Jsrevival Ltd | Administrative & support | 2021 |
| JSW Fabrications Limited | Construction | 2018 |
| JT Offshore Services Ltd | Mining & quarrying | 2021 |
| Jubilee Coaches (Rollesby) Ltd | Transport & logistics | 2016 |
| Juffco Ltd | Professional & scientific | 2011 |
| Juniper Crimson Limited | Real estate | 2021 |
| Just One Fashion Ltd | Wholesale & retail | 2023 |
| Just Pets Ltd | Wholesale & retail | 2019 |
| Just Send This Community Interest Company | Other services | 2026 |
| JW Heat-Tec Limited | Construction | 2022 |
| JW Roofing Services Limited | Construction | 2017 |