| Little Miss Music Management Ltd | Arts & recreation | 2011 |
| Little Newbridge Management Company Ltd | Real estate | 2018 |
| Little Winnick Limited | Hospitality | 2012 |
| Live Fish Food by Post Ltd | Wholesale & retail | 2024 |
| Live Life Care Limited | Health & social care | 2005 |
| LJH Management Limited | Professional & scientific | 2024 |
| Llawnroc Properties Limited | Real estate | 2022 |
| Lloyd Jones Property Consultants Ltd | Professional & scientific | 2023 |
| Lloydbradley Brands Ltd | Professional & scientific | 2016 |
| LOC Holdings Ltd | Financial services | 2023 |
| Loda Cornwall Ltd | Real estate | 2018 |
| Logans Court Management Company Limited | Households | 2003 |
| Longmeadow View Management Company Limited | Households | 2005 |
| Longshore Newquay Limited | Hospitality | 1948 |
| Longstone House Management Limited | Households | 2012 |
| Longtayen Properties Limited | Wholesale & retail | 1972 |
| Looe Indian Cuisine Ltd | Hospitality | 2018 |
| Looe Indian Dining Limited | Real estate | 2017 |
| Lore and Hale Ltd | Administrative & support | 2025 |
| Lorraine Mears Accountancy Ltd | Professional & scientific | 2007 |
| Lost Planet Ltd | Real estate | 2009 |
| Louise Midgley Communications Limited | Professional & scientific | 2014 |
| Lovell Data Ltd | Information & communication | 2024 |
| Lowarth Landscaping Supply UK Ltd | Administrative & support | 2023 |
| Lowena Homes Limited | Construction | 2001 |
| Lowenek Hair & Beauty Ltd | Other services | 2010 |
| Lowe’S Entertainment Ltd | Arts & recreation | 2025 |
| Loyal BEE Care Group Ltd | Health & social care | 2021 |
| LPD (SW) Limited | Construction | 2014 |
| LRD Southwest Ltd | Wholesale & retail | 2020 |
| LSC (Cornwall) Ltd | Construction | 2026 |
| LSR Construction Ltd | Construction | 2018 |
| LT Transport Ltd | Transport & logistics | 2023 |
| LTF Services (SW) Ltd | Construction | 2010 |
| Lucie Jane Studio Ltd | Professional & scientific | 2025 |
| Luckyduck the Label Ltd | Wholesale & retail | 2026 |
| Lucronex Ltd | Administrative & support | 2025 |
| Luke Murray Co Ltd | Information & communication | 2026 |
| Luke Tiller Plumbing & Heating Ltd | Construction | 2023 |
| Lumina Live UK Ltd | Professional & scientific | 2025 |
| Lundy Consulting Ltd | Professional & scientific | 2021 |
| Lundy Offshore Ltd | Professional & scientific | 2024 |
| LUS CC Ltd | Construction | 2022 |
| Lusty 133 Ltd | Wholesale & retail | 2025 |
| Lusty Glaze Project Limited | Construction | 2015 |
| Lusty's Finishing Ltd | Manufacturing | 2015 |
| Luval Medical Ltd | Health & social care | 2022 |
| LUX Retreats Limited | Real estate | 2017 |
| Luxpal Property Group Ltd | Construction | 2025 |
| Luxyl.Co Ltd | Wholesale & retail | 2020 |
| LWS Plastering Ltd | Construction | 2026 |
| Lyndy Lou's Ltd | Wholesale & retail | 2019 |
| Lynher Dairies Cheese Company Limited | Hospitality | 2000 |
| Lynher Dairy Limited | Manufacturing | 1997 |
| Lynn Logic Ltd | Professional & scientific | 2023 |
| Lynwood Gardens (Management) Company Limited | Real estate | 2014 |
| Lyonesse Limited | Manufacturing | 2013 |
| M & C Cuisine Ltd | Hospitality | 2025 |
| M a Broom Limited | Administrative & support | 2019 |
| M a Homes (Kernow) Limited | Real estate | 2017 |
| M Baylis Associates Ltd | Professional & scientific | 2015 |
| M C Squared Design Limited | Professional & scientific | 2014 |
| M Everall Consultancy Ltd | Construction | 2014 |
| M J Burrell Tyres Limited | Wholesale & retail | 2010 |
| M J England Strategic Management Services Limited | Professional & scientific | 2014 |
| M J Higham Limited | Financial services | 2010 |
| M J Kemp Electrical Ltd | Construction | 2013 |
| M L Richardson Property Ltd | Real estate | 2021 |
| M N Bookkeeping Services Limited | Wholesale & retail | 2024 |
| M Stevens Construction Limited | Construction | 2019 |
| M Stevens Property Assets Limited | Real estate | 2025 |
| M&Y Homes Ltd | Real estate | 2020 |
| M.M. Developments (Truro) Limited | Real estate | 1998 |
| MA 023 Ltd | Arts & recreation | 2019 |
| MA Ventilation Services Ltd | Manufacturing | 2014 |
| MA020 Limited | Energy | 2014 |
| MA24 Holdings Limited | Financial services | 2020 |
| MA24 Limited | Construction | 2010 |
| Maapp Property Holdings Ltd | Real estate | 2019 |
| Macintosh Property Management Ltd | Real estate | 2025 |
| Mackenzie Glass Limited | Manufacturing | 2017 |
| Macsalvors (Plant Hire) Limited | Administrative & support | 1967 |
| Mada Events Limited | Other services | 2015 |
| Maddula Enterprises Ltd | Health & social care | 2026 |
| Made Marion Gluten Free Limited | Wholesale & retail | 2016 |
| Madeleine Olivia Limited | Information & communication | 2021 |
| Madison Close Freeholders Limited | Households | 2013 |
| Madison Mews (Hayle) Management Company Limited | Households | 2008 |
| Magenta Investments Limited | Real estate | 1999 |
| Mainstay Property Ltd | Administrative & support | 2017 |
| Maitland CA Ltd | Professional & scientific | 2025 |
| Malabar Chippy & Chicken House Ltd | Wholesale & retail | 2019 |
| Malabar Stores Limited | Wholesale & retail | 2015 |
| Maldidenti Ltd | Health & social care | 2019 |
| Malpas Capital Limited | Real estate | 2022 |
| Malt Southwest Heating Solutions Limited | Manufacturing | 2025 |
| Malwa Stores Ltd | Wholesale & retail | 2026 |
| MAM Agency Limited | Wholesale & retail | 2011 |
| Mama Africa Cornwall Limited | | 2011 |
| Manage Europe Limited | Professional & scientific | 2008 |