| Jonx Ltd | Health & social care | 2018 |
| Jorobacroft Ltd | Wholesale & retail | 2023 |
| Joseph House (Holdings) Ltd | Financial services | 2016 |
| Joseph Kinerman Studios Limited | Professional & scientific | 2024 |
| Jotmans Hall Primary School | Education | 2011 |
| JP Traditional Plastering Services Ltd | Construction | 2022 |
| JPC Services (Benfleet) Limited | Information & communication | 2011 |
| JPD Properties Herts Ltd | Real estate | 2016 |
| JPP House Ltd | Real estate | 2024 |
| JR Certification Limited | Real estate | 2026 |
| JRC Trading Ltd | Hospitality | 2021 |
| JRF Medical Services Ltd | Health & social care | 2023 |
| JRM Consult Limited | Professional & scientific | 2007 |
| JS Investments Limited | Professional & scientific | 2022 |
| JS Service Limited | Health & social care | 2015 |
| Jsdna Holding Limited | Professional & scientific | 2023 |
| JSE Finishings Ltd | Other services | 2021 |
| JSE Projects Ltd | Professional & scientific | 2020 |
| JSJ Electrical Ltd | Construction | 2022 |
| JTM Homes & Lettings Limited | Real estate | 2023 |
| JTO Investments Ltd | Arts & recreation | 2018 |
| Juno Highway Services Ltd | Construction | 2021 |
| Jupiter Facilities Management Limited | Construction | 2003 |
| Jurome Restorations Limited | Manufacturing | 2022 |
| Just 83 Limited | Real estate | 2021 |
| Just Souvlaki Ltd | Hospitality | 2023 |
| Just US Flyers Ltd | Arts & recreation | 2023 |
| Justcallmereg Ltd | Education | 2009 |
| JVF Training Ltd | Professional & scientific | 2026 |
| Jvjgroup Ltd | Construction | 2025 |
| JVO Futures Ltd | Extraterritorial | 2014 |
| K & H Acquisitions Limited | Real estate | 2021 |
| K Barazi Sprinklers Limited | Construction | 2016 |
| K D Property Management Services Limited | Real estate | 2018 |
| K F S Recruitment Limited | Administrative & support | 2016 |
| K I S Education Solutions Limited | Other services | 2009 |
| K J Tween Consultancy Ltd | Professional & scientific | 2022 |
| K M Welding UK Limited | Construction | 2003 |
| K R Construction & Roofing Ltd | Construction | 2017 |
| K. Burrett Cleaning Services Limited | Administrative & support | 2014 |
| K.C. Car Sales (Kent) Limited | Wholesale & retail | 1999 |
| K.Humphries Limited | Administrative & support | 2023 |
| K.J. Green Optical Limited | Health & social care | 2016 |
| K9 Response Limited | Other services | 2023 |
| K9 Services Limited | Other services | 2018 |
| Kaali Boutique Ltd | Wholesale & retail | 2023 |
| Kaeron Limited | Information & communication | 2025 |
| Kahn Analytics Ltd | Administrative & support | 2024 |
| Kalma Health Beauty and Tanning Limited | Other services | 2005 |
| Kapow Artists Ltd | Arts & recreation | 2013 |
| Kare Services Ltd | Information & communication | 2020 |
| Karsson Hawke Environmental Limited | Administrative & support | 2004 |
| Kart Kinetics Ltd | Extraterritorial | 2011 |
| Karubu Ltd | Professional & scientific | 2016 |
| KAS Perfect Vision Limited | Health & social care | 2008 |
| KAS Suspension Limited | Administrative & support | 2015 |
| Kayden Limited | Wholesale & retail | 2013 |
| Kazgar Property Limited | Real estate | 2024 |
| KBL Logistics Ltd | Transport & logistics | 2025 |
| KCE Property Limited | Real estate | 2019 |
| Kdclothing Ltd | Wholesale & retail | 2024 |
| Kellmate Limited | Wholesale & retail | 1994 |
| Kenningtons Consultants Ltd | Professional & scientific | 2017 |
| Kensington Garden Furniture Ltd | Administrative & support | 2011 |
| Kent Kraft Industrial Solutions Ltd | Construction | 2022 |
| Kent Kraft Installation Services Ltd | Construction | 2019 |
| Kent's Hill Local Ltd | Wholesale & retail | 2024 |
| Kentish Scents Ltd | Manufacturing | 2020 |
| Kentkraft Ltd | Construction | 2002 |
| Kents Hill Construction Ltd | Construction | 2021 |
| Kents Property Holdings Limited | Construction | 2021 |
| Kerr Forge Ltd | Education | 2022 |
| Kerridge L Consultants Ltd | Construction | 2017 |
| Kestrel Arboricultural Services Limited | Agriculture & fishing | 2017 |
| KEV Munn Limited | Transport & logistics | 2015 |
| Kevin Delaney Golf Ltd | Arts & recreation | 2017 |
| KHL Technical Services Ltd | Construction | 2013 |
| Khpm Ltd | Construction | 2023 |
| Kidet Ltd | Construction | 2013 |
| Kiisna Limited | Hospitality | 2021 |
| Killer Point Ltd | Wholesale & retail | 2016 |
| Kimac Bathing Solutions Ltd | Construction | 2018 |
| KIN Khao Ltd | Wholesale & retail | 2025 |
| Kindred Care Group Ltd | Health & social care | 2022 |
| Kindrel Ltd | Hospitality | 2025 |
| Kingfisher Building Contractors Limited | Construction | 1997 |
| Kingfisher Engineering Solutions Ltd | Professional & scientific | 2024 |
| Kingfisher Services Essex Limited | Wholesale & retail | 2002 |
| Kingham Legal Consultancy Ltd | Professional & scientific | 2023 |
| Kingsdown Engineering Limited | Administrative & support | 2017 |
| Kingston One Group Limited | Hospitality | 2019 |
| Kingstons Wealth Management Limited | Financial services | 2015 |
| Kingstons Will & Trust Planning Limited | Professional & scientific | 1997 |
| Kingswood Roofing Ltd | Construction | 2002 |
| Kinn Associates Limited | Professional & scientific | 2010 |
| KIP Mcgrath Southend West LLP | | 2021 |
| Kite Advisory Limited | Professional & scientific | 2024 |
| KL Nails & Spa Limited | Other services | 2019 |
| Klar Drinks Ltd | Wholesale & retail | 2018 |
| KLC Steel Fabrications Ltd | Construction | 2026 |