| Kerrier Homecare Limited | Health & social care | 2013 |
| Kevren CIC | Education | 2024 |
| KEW Vivian Management Ltd | Real estate | 2025 |
| Key Diving Limited | Other services | 1981 |
| Keydell Properties Ltd | Real estate | 2020 |
| Khan Cabs Redruth Ltd | Transport & logistics | 2025 |
| King of Dirt Ltd | Arts & recreation | 2024 |
| King Property Investments Limited | Real estate | 2020 |
| Kingsbury Flats Management Company Limited | Households | 1979 |
| Kingsley Apex Property Ltd | Construction | 2026 |
| Kirk Hill Wind Farm Limited | Energy | 2014 |
| Kitchen and Co Cornwall Limited | Wholesale & retail | 2017 |
| Kopi Cornwall Ltd | Hospitality | 2026 |
| KPK Builders Limited | Construction | 2012 |
| Kram Construction Limited | Construction | 2007 |
| Kreative Construction Cornwall Ltd | Construction | 2024 |
| Krowji Limited | Administrative & support | 2005 |
| Kudos Displays Ltd | Manufacturing | 2024 |
| Kynsa Cornwall Ltd | Construction | 2025 |
| L Phipps Professional Decorating Ltd. | Construction | 2017 |
| Laitys Carpentry & Joinery Ltd | Construction | 2025 |
| Lamborne Commercial Storage Ltd | Transport & logistics | 2021 |
| Lamellion Court Apartment Management Company Limited | Real estate | 2014 |
| Lamellion Court Estate Management Company Limited | Real estate | 2014 |
| Lamma Foods Limited | Hospitality | 2022 |
| Lamorna Court Management Company Limited | Households | 1986 |
| Landew House Management Limited | Real estate | 2010 |
| Landlords Solutions Ltd | Households | 2025 |
| Lansdowne (SW) Limited | Hospitality | 2018 |
| Lara Scott Ltd | Construction | 2024 |
| Lasermaster Limited | Wholesale & retail | 2000 |
| Last Light Films Limited | Professional & scientific | 2025 |
| Lasting Touch (Cornwall) Ltd | Other services | 2017 |
| Lasting Touch Holisitcs Ltd | Arts & recreation | 2017 |
| Laurence Weaver (SW) Limited | Real estate | 2009 |
| Laws Accountancy Ltd | Professional & scientific | 2008 |
| Lead and Belong Limited | Professional & scientific | 2025 |
| Lead Discovery Ltd | Wholesale & retail | 2020 |
| Lead Spark SW Ltd | Professional & scientific | 2024 |
| Leathercraft of Cornwall Limited | Manufacturing | 1998 |
| Ledtech Corporation (UK) Limited | Extraterritorial | 2009 |
| Leisurepreneurs Ltd | Administrative & support | 2020 |
| Lena Limited | Hospitality | 2017 |
| Leon Cole Safety & Engineering Ltd | Professional & scientific | 2026 |
| Less 4 Spares Limited | Wholesale & retail | 2010 |
| Letcheck Inventories Limited | Other services | 2004 |
| Life IS TOO Short Holding Company Limited | Financial services | 2025 |
| Life IS TOO Short Limited | Professional & scientific | 2024 |
| Life IS TOO Short Protection Limited | Financial services | 2025 |
| Lifeboat Experiences Limited | Arts & recreation | 2017 |
| Lightwithin Coaching Ltd | Other services | 2023 |
| Lightwithin Therapy and Training Ltd | Health & social care | 2021 |
| Lillie Bros Limited | Wholesale & retail | 2025 |
| Lily B Co Ltd | Administrative & support | 2022 |
| Liminal Therapy Ltd | Health & social care | 2024 |
| Little Hillside Holidays Limited | Hospitality | 2024 |
| Little Vauxhall Limited | Construction | 2017 |
| Live in Rooms SW Limited | Hospitality | 2015 |
| Living Life Direct Ltd | Wholesale & retail | 2026 |
| Livinglanterns Ltd | Manufacturing | 2022 |
| LJ Heating, Plumbing and Property Renovations Ltd | Construction | 2025 |
| LJ Laundry Services Limited | Other services | 2012 |
| LJ Smart Automotive Limited | Wholesale & retail | 2025 |
| Llago Limited | Manufacturing | 2019 |
| Lockley Civils Ltd | Construction | 2015 |
| Logistic Construction Limited | Construction | 2012 |
| Loscombe Developments Ltd | Construction | 2021 |
| Lottefree Ltd | Professional & scientific | 2025 |
| LOU Jones Design Limited | Manufacturing | 1999 |
| LOW LEE Limited | Hospitality | 2021 |
| Lowarth Landscaping Supply Company Ltd | Wholesale & retail | 2016 |
| Lowen BRE Financial Limited | Professional & scientific | 2016 |
| Lowen Harts Day Nursery Limited | Health & social care | 2014 |
| Lowena Community Interest Company | Health & social care | 2007 |
| Loyly Health Recovery & Resilience Ltd | Health & social care | 2020 |
| LPH Electrical Installations Ltd | Construction | 2010 |
| LRM Commercial Solutions Limited | Professional & scientific | 2009 |
| Ludo Tutors Limited | Education | 2017 |
| Luke Roberts Law Ltd | Professional & scientific | 2023 |
| Luna Growth Limited | Financial services | 2026 |
| Luscombe Construction Limited | Construction | 1996 |
| Luxulyan Lettings Ltd | Real estate | 2024 |
| M a E Taxis Limited | Transport & logistics | 2007 |
| M H Flooring Specialists Limited | Construction | 2007 |
| M&M Storage Ltd | Administrative & support | 2018 |
| M&W Meats Limited | Wholesale & retail | 2016 |
| M2 Developments (Cornwall) Limited | Construction | 2014 |
| Macsalvors Limited | Wholesale & retail | 1957 |
| Madd Homes Limited | Real estate | 2013 |
| Madfreds Ltd | Real estate | 2024 |
| Madfreds Squad Ltd | Construction | 2025 |
| Mahers Martial Arts Academy Ltd | Education | 2017 |
| Maid Betsey's Holdings Limited | Financial services | 2024 |
| Maid Betsey's Limited | Real estate | 2024 |
| Malcolm Drew Limited | Wholesale & retail | 1980 |
| Manha Spice House Ltd | Hospitality | 2015 |
| Manhattanlegal Ltd | Professional & scientific | 2025 |
| Manhay Geothermal Limited | Construction | 2024 |
| MAP Estate Agents Limited | Real estate | 2020 |
| MAP Holdings South West Limited | Financial services | 2025 |