| JAI Homes Ltd | Real estate | 2020 |
| JAK Automobile UK Ltd | Wholesale & retail | 2009 |
| James Anthony Byrne Ltd | Extraterritorial | 2026 |
| Jana & Co Accountants Limited | Professional & scientific | 2022 |
| Jane Armstrong Associates Ltd | Professional & scientific | 2014 |
| Jannah Colors Ltd | Manufacturing | 2024 |
| Jarratt Hall Limited | Real estate | 2026 |
| Jarx Ltd | Financial services | 2026 |
| JAS & Karan UK Ltd | Wholesale & retail | 2022 |
| JAS Rehan Ltd | Wholesale & retail | 2021 |
| Jasmar Ltd | Administrative & support | 2018 |
| Jaspal Construction Ltd | Construction | 2026 |
| Jayaraj Natarajan Ltd | Construction | 2025 |
| Jayogla London Ltd | Wholesale & retail | 2023 |
| JB Building & Carpentry Ltd | Construction | 2012 |
| JB Food Supply Ltd | Wholesale & retail | 2024 |
| JB Smart Services Ltd | Construction | 2026 |
| JBM Build Ltd | Construction | 2010 |
| JBM Motors 1980 Ltd | Wholesale & retail | 2011 |
| JD Build Joinery UK Ltd | Construction | 2019 |
| JD Build Ltd | Construction | 2016 |
| JD Global Consultants Ltd | Professional & scientific | 2026 |
| JD Greenwood Ltd | Wholesale & retail | 2018 |
| JD Hair & Beauty Ltd | Wholesale & retail | 2018 |
| JDF Ministries Limited | Other services | 2022 |
| JDL Transportation UK Ltd | Transport & logistics | 2014 |
| JDM Hybrid Parts Ltd | Wholesale & retail | 2019 |
| Jdnc Solutions Ltd | Wholesale & retail | 2025 |
| JDV Holdings Ltd | Real estate | 2024 |
| JED Design and Build Ltd | Construction | 2018 |
| Jeen Fast Foods Ltd | Wholesale & retail | 2015 |
| Jeet Estate Ltd | Real estate | 2025 |
| Jeevana Limited | Health & social care | 2024 |
| Jefferstone Media Limited | Information & communication | 2026 |
| Jeffman Imports Limited | Health & social care | 2006 |
| Jessica Food Ltd | Hospitality | 2021 |
| JET Consultants Ltd | Administrative & support | 2018 |
| JET Education Limited | Education | 2010 |
| JF Scrub Services Ltd | Construction | 2025 |
| JFM Projects Ltd | Construction | 2005 |
| JGK Express Ltd | Transport & logistics | 2025 |
| JGP Cleaning Services Ltd | Administrative & support | 2026 |
| JGS Live Limited | Wholesale & retail | 2022 |
| JH Proco Ltd | Real estate | 2025 |
| JHD Homes Ltd | Real estate | 2021 |
| JHM London Properties Ltd | Real estate | 2020 |
| Jina's Beauty Limited | Other services | 2024 |
| JJ Propertiez Ltd | Real estate | 2024 |
| JJS Pianos Ltd | Transport & logistics | 2025 |
| JJS Solutions Limited | Wholesale & retail | 2012 |
| JK Family Law Ltd | Professional & scientific | 2018 |
| JK Top Solutions Limited | Construction | 2022 |
| JKM Consultancy Limited | Administrative & support | 2016 |
| JLB Travel Limited | Administrative & support | 2022 |
| JLS Construction Ltd | Construction | 2018 |
| JM Tax Consultancy Ltd | Professional & scientific | 2024 |
| JMB Trading Ltd | Wholesale & retail | 2022 |
| JMD Property Holdings Ltd | Real estate | 2026 |
| JMJ Real Estate Limited | Real estate | 2017 |
| JMO & Sons Ltd | Wholesale & retail | 2023 |
| JO & Zack Limited | Wholesale & retail | 2021 |
| JOE Arya Ventilation and Metal Works Ltd | Manufacturing | 2023 |
| Johnsimmy Consulting Limited | Health & social care | 2023 |
| Joker 78 Ltd | Construction | 2018 |
| Jolie Grace Limited | Information & communication | 2024 |
| Jolly Tots Day Nursery Limited | Education | 2016 |
| Jonny Wiles TC Limited | Administrative & support | 2018 |
| Jord Wood Ltd | Construction | 2010 |
| Jose Pizarro Limited | Hospitality | 2014 |
| Jose Pizarro Management Limited | Hospitality | 2015 |
| Josephine Osei Bags Ltd | Wholesale & retail | 2026 |
| José Blanco Engineering Ltd | Wholesale & retail | 2026 |
| José Pizarro Distributions Limited | Wholesale & retail | 2020 |
| Jozwiak Property Ltd | Real estate | 2025 |
| JP Electricians Ltd | Construction | 2020 |
| JP Wine Club Limited | Manufacturing | 2025 |
| JPB Real Estate Limited | Real estate | 2025 |
| Jpml Plastering Ltd | Construction | 2017 |
| JPS Building Solutions Ltd | Construction | 2012 |
| JPS Electrical Solutions Ltd | Construction | 2023 |
| JPS HQ Limited | Administrative & support | 2023 |
| JPS Mechanical Solutions Ltd | Construction | 2023 |
| JPS Spaces Limited | Construction | 2024 |
| JRK Express Ltd | Transport & logistics | 2025 |
| JRL Software Ltd | Information & communication | 2024 |
| JSC Haulage Limited | Transport & logistics | 2006 |
| JSM Furniture Ltd | Manufacturing | 2006 |
| Jstletme Ltd | Hospitality | 2020 |
| JTB Lettings Limited | Real estate | 2023 |
| JTB Property Group Limited | Real estate | 2025 |
| JTC Property Services Limited | Households | 2024 |
| Jugdip Virdee Ltd | Administrative & support | 2009 |
| Juhiran Global Consulting Ltd | Information & communication | 2025 |
| Juliette Johnson Consultancy Limited | Professional & scientific | 2013 |
| Julkon Building Services Limited | Construction | 2011 |
| Julkon Property Ltd | Real estate | 2024 |
| Jupiter Invest Limited | Real estate | 2024 |
| Just Around the Corner Limited | Professional & scientific | 2024 |
| Just Homes and Rooms Ltd | Real estate | 2018 |
| Just in Thai Ltd | Hospitality | 2025 |