| Jajamine Limited | Wholesale & retail | 2018 |
| Jakes N Ladders Limited | Construction | 2006 |
| Jalving Potatoes UK Ltd | Agriculture & fishing | 2006 |
| James Fogarty Coaching Limited | Education | 2026 |
| James Heath & Sons Limited | Agriculture & fishing | 1961 |
| James Jenks Plumbing & Heating Ltd | Construction | 2020 |
| James Michaelson Consultancy Ltd | Professional & scientific | 2017 |
| James Michaelson Portfolio Ltd | Real estate | 2019 |
| James Slaven Limited | Construction | 2016 |
| Jamia Masjid Gousia (Telford) | Education | 2012 |
| Janaki Enterprise Ltd | Real estate | 2021 |
| Janaura Group Ltd | Administrative & support | 2026 |
| Janbo Consulting Ltd | Administrative & support | 2015 |
| Jane Developments Limited | Real estate | 2014 |
| Janisa Solutions Limited | Information & communication | 2024 |
| Janville Healthcare Ltd | Health & social care | 2019 |
| Japanese Shiba INU Rescue Limited | Other services | 2023 |
| Jardine Conservatories Ltd | Construction | 2023 |
| Jardine Upvc Ltd | Construction | 2014 |
| Jarjar Properties Ltd | Real estate | 2019 |
| Jarocin Ltd | Other services | 2019 |
| JAS Kakkar Social Care Consultancy Ltd | Health & social care | 2019 |
| Jasam Ltd | Real estate | 2025 |
| Jasam Rentals Limited | Real estate | 2022 |
| Jasbec Health Ltd | Administrative & support | 2016 |
| Jaskamal Limited | Real estate | 2022 |
| Jasofid Ltd | Other services | 2018 |
| Jason Michael Ollerenshaw & Mandy Louise Gray LLP | | 2007 |
| Jass Gill Limited | Transport & logistics | 2021 |
| Jassfr Limited | Information & communication | 2018 |
| Jastreb Ltd | Other services | 2018 |
| Jaxmil Construction Limited | Construction | 2023 |
| Jaydes Shades Limited | Construction | 2023 |
| Jayne Smith Design Ltd | Professional & scientific | 2010 |
| Jays Removals & Storage Ltd | Transport & logistics | 2009 |
| Jays Van MAN Ltd | Transport & logistics | 2024 |
| Jayyviation Ltd | Manufacturing | 2022 |
| Jazak Ltd | Other services | 2024 |
| Jazumah Healthcare Limited | Health & social care | 2016 |
| JBA Surveying Limited | Professional & scientific | 2020 |
| Jbarparts Ltd | Wholesale & retail | 2026 |
| Jbespoke Ltd | Construction | 2020 |
| Jblr Properties Ltd | Real estate | 2023 |
| JBT Enterprises Ltd | Households | 2015 |
| JC Carpentry and Construction Ltd | Construction | 2023 |
| JC Data & Consultants Ltd | Information & communication | 2025 |
| JC Racking Installations Limited | Construction | 2023 |
| Jcameron Construction Ltd | Construction | 2025 |
| JCE & Sons Limited | Construction | 2003 |
| JCN Electrical Services West Midlands Ltd | Construction | 2026 |
| JCS Web-Services Ltd | Information & communication | 2014 |
| JCW Engineering Ltd | Professional & scientific | 2023 |
| JD Agencies Ltd | Professional & scientific | 2025 |
| JD and SP Enterprises Limited | Financial services | 2021 |
| JD Wise Holdings Ltd | Financial services | 2025 |
| Jdlx Services Limited | Professional & scientific | 2025 |
| JDM Chef Ltd | Hospitality | 2026 |
| JDM Presale Consultants UK Ltd | Professional & scientific | 2025 |
| JDN Sparta Ltd | Construction | 2026 |
| JDS Food Supplies Ltd | Hospitality | 2026 |
| Jd’S Caribbean Food Ltd | Wholesale & retail | 2020 |
| Jeevan Optical Limited | Health & social care | 2014 |
| Jeffrey James Restaurant UK Limited | Hospitality | 2025 |
| Jegar Ltd | Education | 2026 |
| Jeli Holidays Ltd | Real estate | 2022 |
| JEM Fitness Ltd | Arts & recreation | 2024 |
| Jems Driver Training Ltd | Education | 2020 |
| Jenal Ltd | Other services | 2020 |
| Jenross Ltd | Real estate | 2019 |
| Jervis Harris Developments (NO 2) LLP | | 2019 |
| Jesaka Taylor Limited | Financial services | 2024 |
| Jetlife Limited | Public administration | 2015 |
| Jeynger Ltd | Health & social care | 2018 |
| Jeztech Limited | Information & communication | 2017 |
| JFL Cooling Services Limited | Construction | 2022 |
| JG Property Enterprise Ltd | Real estate | 2021 |
| JH Accounting & Payroll Services Limited | Professional & scientific | 2016 |
| JH Electrician Services Ltd | Construction | 2022 |
| JHA Bathrooms Limited | Construction | 2024 |
| Jhaynesleisure Ltd | Wholesale & retail | 2024 |
| Jhsk Limited | Extraterritorial | 2024 |
| Jigsaw Aviation Limited | Education | 2020 |
| Jigsaw Building Ltd | Construction | 2024 |
| Jimeth Ltd | Information & communication | 2017 |
| Jimmy's Barbershop Ltd | Other services | 2017 |
| Jimpy Holdings Limited | Financial services | 2025 |
| Jitic Ltd | Information & communication | 2019 |
| JJ Speedy Logistics Ltd | Transport & logistics | 2018 |
| JJG Computer Consultants Ltd | Information & communication | 1998 |
| JJM Body Repair Ltd | Wholesale & retail | 2021 |
| JK Furnitures Ltd | Manufacturing | 2020 |
| JK Prints Ltd | Manufacturing | 2025 |
| JK Strategic Solutions Limited | Professional & scientific | 2020 |
| JK Tyres Limited | Extraterritorial | 2003 |
| Jk's - Comfort Food & Culture Ltd | Hospitality | 2023 |
| JL Davies Property Ltd | Real estate | 2023 |
| JL Security Ltd | Administrative & support | 2017 |
| Jlbz Ltd | Real estate | 2013 |
| JMC Automotive Ltd | Wholesale & retail | 2025 |
| JMC IT Services Ltd | Information & communication | 2007 |