| JAM Music Services Limited | Professional & scientific | 2017 |
| James Mcqueen Art Limited | Other services | 2020 |
| James Penny Ltd | Other services | 2020 |
| Jamsons Geotechnics Ltd | Construction | 1999 |
| Janes Educational C.I.C. | Education | 2015 |
| Janes Entertainment Ltd | Arts & recreation | 2015 |
| JAP Media Limited | Professional & scientific | 2013 |
| Japanese Knotweed Group Ltd | Administrative & support | 2006 |
| Japanese LUX Furniture Ltd | Wholesale & retail | 2024 |
| JAR Agencies Limited | Wholesale & retail | 2021 |
| Jasmine Alexander Limited | Information & communication | 2014 |
| Jawco Properties Limited | Real estate | 2017 |
| JB Accounting and Financials Limited | Professional & scientific | 2014 |
| JBR Investment Ltd | Real estate | 2024 |
| JC Roofing and Lofts Limited | Construction | 2019 |
| JCF Contract Services Limited | Construction | 2024 |
| Jclm Enterprise Limited | Manufacturing | 2025 |
| JCM Residential Ltd | Real estate | 2015 |
| JD Days Productions Limited | Information & communication | 2025 |
| JDP Scaffolding Ltd | Construction | 2019 |
| Jenna's Nails & Beauty Ltd | Other services | 2023 |
| Jerky G'S Kitchen Ltd | Hospitality | 2016 |
| Jetpack Energy Limited | Administrative & support | 2018 |
| Jeymee Holding Ltd | Financial services | 2025 |
| Jeymee Properties Limited | Real estate | 2025 |
| JHK Cleaning Services Limited | Other services | 2015 |
| Jicpops Limited | Professional & scientific | 1997 |
| Jimbo, Gefro & Bimbo Limited | Real estate | 2024 |
| JJ Properties 2016 Limited | Administrative & support | 2013 |
| Jjoyce Craft Construction Limited | Construction | 2026 |
| Jjoyce Homes Limited | Financial services | 2026 |
| JKH Software Consulting Ltd | Information & communication | 2017 |
| JL Build Ltd | Construction | 2023 |
| JL Stores Limited | Wholesale & retail | 2016 |
| Jlad Limited | Construction | 2013 |
| JLD 77 Ltd | Administrative & support | 2023 |
| JMH Architects Limited | Professional & scientific | 2023 |
| Jmint Creative Ltd | Professional & scientific | 2018 |
| Jnstn Ltd | Information & communication | 2017 |
| JO OJ Limited | Professional & scientific | 2025 |
| John Charles Shutters Ltd | Construction | 2023 |
| Johnson IP Technology Ltd | Information & communication | 2019 |
| Johnson Real Estate Ltd | Real estate | 2023 |
| Joint Facilities Management Limited | Administrative & support | 2016 |
| Jonathan GAL Limited | Professional & scientific | 2002 |
| Jones the Hairdresser Ltd | Other services | 2013 |
| Jorges Salman Architects Limited | Professional & scientific | 2014 |
| Joseph Harrington Limited | Professional & scientific | 2011 |
| JPM Resourcing Limited | Administrative & support | 2014 |
| Jpsf Consultancy Limited | Other services | 2020 |
| JR Egaming Solutions Ltd | Information & communication | 2021 |
| JT Training & Assessing Ltd | Transport & logistics | 2023 |
| Jtmc Consulting Limited | Administrative & support | 2009 |
| Juki Music Limited | Information & communication | 2006 |
| Julienne a. Leonard Limited | Professional & scientific | 2016 |
| Jumbo Project Management Ltd | Construction | 2023 |
| Just in Consulting Limited | Real estate | 2014 |
| Just Kiddies Limited | Other services | 2024 |
| Just Scaffolding (Surrey) Limited | Construction | 2016 |
| JWE Fine Art Limited | Arts & recreation | 2015 |
| K & K Forensic Investigations Limited | Administrative & support | 2016 |
| K & W Fabrications Limited | Water & waste | 1985 |
| K D Bloyce Limited | Other services | 2013 |
| K J Earl Limited | Construction | 2015 |
| K P H Trading Limited | Real estate | 2004 |
| K&R Carpentry Ltd | Construction | 2007 |
| K.P.H. Environmental Services Ltd | Administrative & support | 2001 |
| K2 Fire & Security Ltd | Administrative & support | 2022 |
| Kaavin Properties Limited | Real estate | 2019 |
| Kaizenic Solutions Limited | Information & communication | 2025 |
| KAJ Trading Ltd | Wholesale & retail | 2015 |
| KAJ Wholesale Ltd | Wholesale & retail | 2021 |
| Kalandora Limited | Construction | 2016 |
| Kandoo Properties Ltd | Real estate | 2019 |
| Karen Hicks Training Academy Ltd | Education | 2020 |
| Kasado Consulting Limited | Administrative & support | 2018 |
| Kassapapa Ltd | Extraterritorial | 2025 |
| Kathryn Lodge Limited | Professional & scientific | 2016 |
| Katom House Ltd | Real estate | 2023 |
| Katsanos Engineering Consultancy Ltd | Administrative & support | 2007 |
| KDP Topping Limited | Construction | 2019 |
| Keepie Uppie Football Ltd | Arts & recreation | 2013 |
| Keeping Account Limited | Information & communication | 2025 |
| Keidal LLP | | 2011 |
| Keith Campbell Consulting Limited | Information & communication | 2011 |
| Kelf Civil Engineering Ltd | Construction | 2021 |
| Kellysbigtrip Limited | Administrative & support | 2015 |
| Kenley Estates Ltd | Real estate | 2017 |
| Kenley Financial Limited | Financial services | 2003 |
| Kennedysound Ltd | Information & communication | 2022 |
| Kenny Family Real Estate Limited | Real estate | 2017 |
| Kent Glass & Glazing Limited | Construction | 2013 |
| Kent GUN Club Limited | Arts & recreation | 2003 |
| Kent Residential Developments Limited | Real estate | 2017 |
| Keranne Kondjo Ltd | Education | 2020 |
| Kesse Limited | Real estate | 2026 |
| Keston Plant Sales Ltd | Administrative & support | 2025 |
| Kevin Macadam Limited | Information & communication | 2014 |
| Keystone Construction Marketing Ltd | Professional & scientific | 2011 |
| Keywise Talent Solutions Ltd | Administrative & support | 2024 |