| J D Safety Engineering Limited | Professional & scientific | 2024 |
| J F Hornby Group Limited | Administrative & support | 2009 |
| J F Hornby Limited | Professional & scientific | 2009 |
| J G Black Polymers 2016 Limited | Manufacturing | 2016 |
| J R Gabriel Properties Limited | Real estate | 2012 |
| J.G. Black Polymers Limited | Real estate | 1992 |
| J.S. Cole Limited | Transport & logistics | 1989 |
| J1 Consultancy Limited | Professional & scientific | 2020 |
| Jades Brewstop Ltd | Hospitality | 2026 |
| James Hillen Construction Ltd | Construction | 2026 |
| James Wearing Plumbing and Heating Limited | Construction | 2015 |
| Jayne Dennison Physiotherapy Limited | Administrative & support | 2013 |
| JB Marine Services Limited | Other services | 2015 |
| JBS Cumbria Limited | Financial services | 2009 |
| JEL Medical Limited | Health & social care | 2025 |
| JEM Lettings Ltd | Real estate | 2015 |
| Jepero Limited | Wholesale & retail | 2002 |
| Jess Dandy Productions Ltd | Arts & recreation | 2026 |
| Jetties and Moorings Limited | Transport & logistics | 2016 |
| JH Holdings (Cumbria) Limited | Financial services | 2026 |
| JJC (North West) Limited | Administrative & support | 2020 |
| JJR Rentals Limited | Real estate | 2015 |
| JJT Woodland Services Ltd | Agriculture & fishing | 2024 |
| JK (FC) Pension Trustees Ltd | Financial services | 2006 |
| JKH Telecomms Limited | Information & communication | 2015 |
| JLS Technologies Limited | Professional & scientific | 2018 |
| JMG Buy to LET Limited | Real estate | 2023 |
| JO Greenfield Ltd | Professional & scientific | 2018 |
| John Bamford Ltd | Construction | 2006 |
| John Barr Slates Limited | Wholesale & retail | 1994 |
| John Curtis Construction Limited | Construction | 1999 |
| John Curtis Holdings Limited | Professional & scientific | 2009 |
| John Fowler & Co (Leeds) Limited | Manufacturing | 2003 |
| John Fowler & Co Assets Limited | Financial services | 2020 |
| John Keen (Financial Control) Limited | Professional & scientific | 2003 |
| John Lambert (North West) Limited | Construction | 2004 |
| John Miller and Sons Limited | Water & waste | 2005 |
| Joma Enterprises Limited | Real estate | 2020 |
| JON Mccullough Limited | Construction | 2011 |
| Jonathan B Jackson Limited | Administrative & support | 2011 |
| Jonathan Bryson Consulting Limited | Professional & scientific | 2010 |
| Joshua Edwards Limited | Administrative & support | 2013 |
| JR Casson Ltd | Wholesale & retail | 2024 |
| JR Wilson Ltd | Construction | 2009 |
| JS & JG Ltd | Real estate | 2021 |
| JS Contract Cleaning Ltd | Administrative & support | 2012 |
| JS Property (Eastbourne) Limited | Real estate | 2021 |
| JS ROV Audit and Consultancy Limited | Manufacturing | 2016 |
| JT Storage Solutions Limited | Transport & logistics | 2025 |
| JWT Safety Limited | Other services | 2012 |
| K & S Enterprises Ltd | Hospitality | 2007 |
| K and J Morgan Holdings Limited | Professional & scientific | 2022 |
| K Anders Forestry Ltd | Agriculture & fishing | 2023 |
| K Fisher Limited | Construction | 2013 |
| K&M Awareness Limited | Information & communication | 2026 |
| Kadapt Ltd | Manufacturing | 2016 |
| Karman Line Consulting Limited | Information & communication | 2026 |
| KAY Jackson Limited | Other services | 2013 |
| KCY Consultants Limited | Professional & scientific | 2023 |
| Keith Edwards Motors Limited | Wholesale & retail | 2002 |
| Kendal Grill Ltd | Hospitality | 2026 |
| Kenilford Ltd | Arts & recreation | 2012 |
| Kerry Bellman Limited | Other services | 2007 |
| Kerryn Ellan Tattoo Ltd | Arts & recreation | 2023 |
| Keswick to Barrow Walk | Administrative & support | 2017 |
| Kindred Spirit Cocktails Limited | Hospitality | 2019 |
| Kindred Spirit Events Limited | Hospitality | 2024 |
| King Street Ulverston Limited | Administrative & support | 2017 |
| Koati Ltd | Information & communication | 2016 |
| Koncept Collective Limited | Arts & recreation | 2025 |
| Koru Investments Limited | Financial services | 2025 |
| KPH Consultants Limited | Professional & scientific | 2019 |
| Kruger Coverings Limited | Construction | 2024 |
| Kudelski Contract Services Ltd | Manufacturing | 2019 |
| L & S Leisure Barnsley Ltd | Hospitality | 2014 |
| L G Technical Services Limited | Professional & scientific | 2000 |
| L&O Property Group Ltd | Administrative & support | 2026 |
| L'Al Churrasco Limited | Hospitality | 2018 |
| L.H.J. Solutions Limited | Professional & scientific | 1997 |
| L3D Lighting Ltd | Construction | 2018 |
| LA12 Ltd | Professional & scientific | 2012 |
| LA12 Systems Ltd | Administrative & support | 2025 |
| Lady Cumbria Ltd | Real estate | 2020 |
| Lake District Farmers Ltd | Manufacturing | 2009 |
| Lake District Green Limited | Hospitality | 2015 |
| Lake District Lobster and Seafood Limited | Wholesale & retail | 2020 |
| Lake District Production Services Limited | Arts & recreation | 2017 |
| Lake District Retreats Limited | Hospitality | 2023 |
| Lake District Tea Company Limited | Wholesale & retail | 2022 |
| Lakeland Aggregates Limited | Wholesale & retail | 2001 |
| Lakeland Building Limited | Construction | 2024 |
| Lakeland Care & Support Services Limited | Health & social care | 2008 |
| Lakeland Community Properties Limited | Real estate | 2021 |
| Lakeland Picnic Limited | Wholesale & retail | 2006 |
| Lakeland Pony Treks Ltd | Agriculture & fishing | 2016 |
| Lakeland Property Group Limited | Real estate | 2025 |
| Lakeland Stonemasonry Ltd | Manufacturing | 2025 |
| Lakeland Therapy Ltd | Health & social care | 2022 |
| Lakeland Vista Limited | Administrative & support | 2023 |
| Lakelandpikes Property Ltd | Households | 2019 |