| Keastbeat Limited | Households | 1991 |
| Keay Developments Limited | Construction | 2019 |
| Keeled Moon Ltd | Information & communication | 2025 |
| Keep IT Simple Organisation Ltd | Professional & scientific | 2010 |
| Keepsafe Security Services Limited | Administrative & support | 1992 |
| Keheren Therapy Limited | Health & social care | 2015 |
| Keir Townsend Limited | Professional & scientific | 2010 |
| Kembery Glazing Ltd | Construction | 2017 |
| Keosetech Ltd | Information & communication | 2023 |
| Kerdene Limited | Extraterritorial | 2000 |
| Kernick Storage Containers Limited | Other services | 2020 |
| Kernow Beat C.I.C. | Information & communication | 2025 |
| Kernow Coatings Limited | Manufacturing | 1973 |
| Kernow Colours Ltd | Wholesale & retail | 2024 |
| Kernow Community Leisure Limited | Education | 2013 |
| Kernow International Group Limited | Professional & scientific | 2026 |
| Kernow Kars Ltd | Wholesale & retail | 2014 |
| Kernow Motorworks Ltd | Wholesale & retail | 2024 |
| Kernow Ocean Racing Ltd | Professional & scientific | 2024 |
| Kernow Scaffolding Ltd | Construction | 2024 |
| Kernow Waste Disposal & Aggregates Ltd | Water & waste | 2025 |
| Kernu Ltd | Information & communication | 2012 |
| Kevri Ltd | Education | 2021 |
| Key Machine Limited | Other services | 2015 |
| Killey Consulting Ltd | Administrative & support | 2020 |
| Kinetic Creative Limited | Information & communication | 2010 |
| Kingsley Gardens (Westward HO!) Limited | Real estate | 2021 |
| KLE Solutions (UK) Limited | Construction | 2008 |
| Knights of Borria Ltd | Information & communication | 2020 |
| Koha Architects Ltd | Professional & scientific | 2012 |
| Koolkare Limited | Manufacturing | 1998 |
| Kota Sound Limited | Professional & scientific | 2017 |
| KPR Holdings Ltd | Real estate | 2020 |
| Kreft Films Ltd | Arts & recreation | 2022 |
| Kreftor Ltd | Construction | 2020 |
| Kreftow Kernewek Limited | Professional & scientific | 2016 |
| Kumi Ltd | Wholesale & retail | 2019 |
| Kwikpay Limited | Information & communication | 2013 |
| L.P.J Cornwall Ltd | Transport & logistics | 2021 |
| Lamorna Property Management Ltd | Households | 2006 |
| Lanhydrock Exploration Services Ltd | Professional & scientific | 2026 |
| Laser Industries Holdings Limited | Financial services | 2024 |
| Laser Industries Limited | Manufacturing | 1996 |
| Latham Andrews Ltd | Information & communication | 2014 |
| Lawer Brothers Limited | Mining & quarrying | 1961 |
| LC Blackburn Ltd. | Manufacturing | 2009 |
| Lead IT LAB Ltd | Information & communication | 2023 |
| Lemara Property Ltd | Real estate | 2024 |
| Lesjofors Heavy Springs UK Limited | Manufacturing | 1977 |
| Letter Box Hamper Company Limited | Hospitality | 2014 |
| Levick & Jenkin Limited | Construction | 2015 |
| Lewis Haughton Limited | Wholesale & retail | 2023 |
| Lexidoc Document Services Limited | Professional & scientific | 2012 |
| Lifetime Learning (Penryn) Limited | Health & social care | 2025 |
| Lightwater Environmental Limited | Transport & logistics | 2008 |
| Lincoln Bespoke Flooring Ltd | Construction | 2014 |
| Linenfields Limited | Wholesale & retail | 2007 |
| Link Chiropractic Limited | Health & social care | 2007 |
| Livingstone ST Ives Ltd | Wholesale & retail | 2018 |
| Llawnroc Lettings Limited | Real estate | 2020 |
| Llawnroc Project Management Ltd | Construction | 2017 |
| Lockwood Construction (SW) Ltd | Construction | 2018 |
| Long Mynd Cider Ltd | Manufacturing | 2026 |
| Loot Chest Retail Ltd | Wholesale & retail | 2019 |
| Lougabe Limited | Hospitality | 2019 |
| Lounge of Lewes Limited | Wholesale & retail | 2010 |
| Loveday Distilling Ltd | Manufacturing | 2023 |
| Lower Treluswell Barn Management Limited | Administrative & support | 1999 |
| LTL Fitness Ltd | Arts & recreation | 2014 |
| Ludophoria Ltd | Information & communication | 2021 |
| Lupe Ltd | Hospitality | 2021 |
| LUX Fashion Boutique Ltd | Wholesale & retail | 2025 |
| LZ Asset Management Ltd | Real estate | 2020 |
| M & C Opperman Ltd | Health & social care | 2017 |
| M and G Refurbishments Limited | Construction | 2018 |
| M&B Sports & Social Club Limited | Administrative & support | 2010 |
| Mahamasala Spice Kitchen Limited | Hospitality | 2018 |
| Maki Esports Ltd | Extraterritorial | 2021 |
| Management Company for the Old Village Stores Godolphin Limited | Households | 2008 |
| Mance Communications Limited | Professional & scientific | 2020 |
| Manor Court (Penryn) Management Company Limited | Households | 1991 |
| Manta Makes Limited | Manufacturing | 2015 |
| Many Hands Workshop Ltd | Manufacturing | 2022 |
| Margo Interiors Ltd | Construction | 2015 |
| Marine Court (Falmouth) Limited | Households | 1993 |
| Mariners Penryn Ltd | Hospitality | 2017 |
| Mark Shaw Photography Ltd | Professional & scientific | 2022 |
| Marnick Roofing Limited | Construction | 2008 |
| Marraum Ltd | Professional & scientific | 2013 |
| Marstel Ltd | Hospitality | 2003 |
| Martin Incorporated Ltd. | Hospitality | 1999 |
| Master Agreements Limited | Professional & scientific | 2006 |
| Mavfore Limited | Households | 1982 |
| MC Utilities & Civils Ltd | Construction | 2021 |
| Mccoull Holdings Limited | Real estate | 2015 |
| ME 2 YOU Taxis Limited | Transport & logistics | 2025 |
| Meat LAB Ltd | Hospitality | 2018 |
| Menagerie Group Limited | Information & communication | 2012 |
| Merchant House (Truro) Limited | Hospitality | 1977 |
| Metal (Holdings) Limited | Professional & scientific | 2014 |