| JCM Scotload Ltd | Extraterritorial | 2002 |
| JCS Engineering (Barrow) Limited | Construction | 2018 |
| JD Plumbing & Heating Installation Limited | Construction | 2006 |
| JDC Digital Ltd | Information & communication | 2024 |
| JDC Project Consultants Limited | Public administration | 2018 |
| Jdcabs Ltd | Transport & logistics | 2025 |
| Jefclinsam Limited | Health & social care | 2017 |
| Jendan Ltd | Health & social care | 2024 |
| Jesus Property Ltd | Construction | 2026 |
| Jetza Limited | Real estate | 2021 |
| JF Overseas Limited | Professional & scientific | 2014 |
| Jgriffiths Property Limited | Real estate | 2025 |
| JIM Redfern Associates Limited | Construction | 2005 |
| JJ Watters Electrical Ltd | Professional & scientific | 2026 |
| JJC Hire Limited | Water & waste | 2007 |
| JJH Quality Management Ltd | Professional & scientific | 2014 |
| JKH (Cumbria) Limited | Arts & recreation | 2008 |
| Jklt Property Group Ltd | Real estate | 2026 |
| JLG Engineering Limited | Administrative & support | 2015 |
| JN Wilson Limited | Other services | 2011 |
| John Hocknell Limited | Construction | 2019 |
| John Hunter & Company(Barrow)Limited | Extraterritorial | 1947 |
| Joined Triangles Limited | Wholesale & retail | 2023 |
| Jonmon Property Ltd | Real estate | 2022 |
| Jonshaw Property Limited | Real estate | 2019 |
| Joseph Business Ltd | Real estate | 2019 |
| Joseph Purdy Productions Ltd | Arts & recreation | 2018 |
| Joyfull Media Limited | Information & communication | 2026 |
| JRE Developments NW Limited | Real estate | 2025 |
| JRH Egineering Ltd | Manufacturing | 2026 |
| JS FAB CON Ltd | Manufacturing | 2025 |
| JSQ Engineering Services Ltd | Professional & scientific | 2026 |
| Jsre Design Limited | Other services | 2016 |
| Jtir Construction Ltd | Construction | 2018 |
| Judd Engineering Limited | Professional & scientific | 2006 |
| JV Design Ltd | Construction | 2014 |
| JWM Management Ltd | Information & communication | 2018 |
| K & S Land Limited | Extraterritorial | 2013 |
| K & V & H Offshore Limited | Extraterritorial | 2012 |
| K Aesthetics Limited | Other services | 2019 |
| K and J Cargo Ltd | Wholesale & retail | 2025 |
| K J & I Property Investments Ltd | Real estate | 2025 |
| K Salisbury ETC Ltd | Manufacturing | 2002 |
| K&C Industrial Services Ltd | Administrative & support | 2018 |
| K&K Decorating Services Ltd | Construction | 2025 |
| K.E.M Ventures Ltd | Wholesale & retail | 2019 |
| K.G Lettings Ltd | Real estate | 2026 |
| Kapadokya Restaurant Ltd | Hospitality | 2025 |
| Karenmc.Com Limited | Information & communication | 2015 |
| Kates Skates Limited | Wholesale & retail | 2018 |
| KAW Projects Limited | Construction | 2004 |
| Kayzer Ltd | Hospitality | 2021 |
| Kbsoloutions Ltd | Professional & scientific | 2025 |
| KD Home Services Ltd | Administrative & support | 2024 |
| Keane Construction (Cumbria) Ltd | Construction | 2020 |
| Keep OUR Future Afloat Company Limited | Other services | 2025 |
| Keiranbakerlogistics Ltd | Transport & logistics | 2024 |
| Keith Brown Electrical Limited | Professional & scientific | 2010 |
| Keith Garnett Engineering Limited | Professional & scientific | 2018 |
| Keith Wilson Electrical Contractors Limited | Manufacturing | 2003 |
| Kelm Consultancy Limited | Professional & scientific | 2022 |
| Kenchristy Afro Asia Food Confectioners Limited | Wholesale & retail | 2026 |
| Kennedy Barrow Limited | Other services | 2019 |
| Kent Electrics Ltd | Manufacturing | 2019 |
| Kent Motor Cars LLP | | 2016 |
| Kerry Lancaster Limited | Other services | 2007 |
| KEW Financial Planning Ltd | Professional & scientific | 2023 |
| KIA Leisure Limited | Hospitality | 1996 |
| Kinetic Hospitality Limited | Hospitality | 2022 |
| Kingfisher Lets Limited | Real estate | 2025 |
| KJM Rentals Ltd | Real estate | 2025 |
| Klass Cleans Limited | Administrative & support | 2020 |
| Klassical Holdings Ltd | Wholesale & retail | 2026 |
| KLG Enterprise Ltd | Wholesale & retail | 2025 |
| KLM Chippie Limited | Wholesale & retail | 2016 |
| KMM Bridal Ltd | Wholesale & retail | 2017 |
| Knife & Sole Ltd | Hospitality | 2023 |
| Knight Promotions Ltd | Hospitality | 2021 |
| Knock OUT Wrestling Academy Ltd | Arts & recreation | 2012 |
| Kotys Construction Ltd | Construction | 2016 |
| Koyar Carwash Ltd | Administrative & support | 2026 |
| KP Property Solutions Ltd | Real estate | 2025 |
| KR Co-Living Ltd | Real estate | 2023 |
| KR Next GEN Ltd | Real estate | 2025 |
| Krystal Clean Co Ltd | Administrative & support | 2026 |
| KS Musicals (Barrow) Community Interest Company | Arts & recreation | 2019 |
| KS Musicals Limited | Administrative & support | 2012 |
| KS Roofing/Building Limited | Construction | 2024 |
| Ksbuilding Ltd | Administrative & support | 2025 |
| KSH Law Limited | Professional & scientific | 2024 |
| Kshetrapal Limited | Health & social care | 2013 |
| Kurt Youngs Construction Limited | Construction | 2019 |
| Kwun Sing Limited | Hospitality | 2018 |
| L and M Farms Ltd | Agriculture & fishing | 2024 |
| L D Plastering Limited | Construction | 2017 |
| L H Maintenance & Cafe Ltd | Construction | 2023 |
| L Thomas Construction Limited | Construction | 2015 |
| L&H Inspection Limited | Manufacturing | 2018 |
| L1 Barber Barrow Ltd | Other services | 2024 |
| LA Construction Barrow Limited | Construction | 2025 |