| Cornwall Anaesthetics Ltd | Health & social care | 2015 |
| Cornwall Breaks Ltd | Hospitality | 2020 |
| Cornwall Building Control Ltd | Professional & scientific | 2012 |
| Cornwall Business Connections Ltd | Administrative & support | 2017 |
| Cornwall Cancer Care Limited | Health & social care | 2019 |
| Cornwall Clinical Services Limited | Professional & scientific | 2013 |
| Cornwall Community Development Limited | Health & social care | 2001 |
| Cornwall Cooling Limited | Construction | 2018 |
| Cornwall Dermatology Limited | Health & social care | 2015 |
| Cornwall Doors Ltd | Construction | 2026 |
| Cornwall Drains Ltd | Water & waste | 2016 |
| Cornwall Eco Heat Ltd | Construction | 2022 |
| Cornwall Fishermen (1988) Auctions Limited | Agriculture & fishing | 1989 |
| Cornwall Hand Surgery Limited | Hospitality | 2015 |
| Cornwall HIP Clinic Limited | Health & social care | 2013 |
| Cornwall Hotels Ltd | Hospitality | 2023 |
| Cornwall Open Studios Limited | Administrative & support | 2024 |
| Cornwall Planning Group Limited | Professional & scientific | 2014 |
| Cornwall Plumber Ltd | Construction | 2023 |
| Cornwall Surveys Ltd | Professional & scientific | 2020 |
| Cornwall Theatre Company Limited | Arts & recreation | 1981 |
| Cornwall Urology Clinic Limited | Health & social care | 2015 |
| Cornwall Yacht Charters Limited | Transport & logistics | 2019 |
| Cornwalls Great Escape Rooms Limited | Arts & recreation | 2016 |
| COT Valley Leisure Limited | Hospitality | 2024 |
| Counselling for Social Change Limited | Health & social care | 2012 |
| County Tradesperson Limited | Construction | 2020 |
| Courthouse Securities Limited | Real estate | 2019 |
| Cove Lamorna Limited | Real estate | 2014 |
| Cove Linen Services Ltd | Other services | 2023 |
| Cove Property Management & Maintenance Limited | Households | 2023 |
| Coyco Limited | Information & communication | 2017 |
| Crago Holdings Limited | Financial services | 2022 |
| Crago Properties Ltd | Households | 2020 |
| Crane & Johnston C&J Ltd | Professional & scientific | 2015 |
| Crantock Tmgs Ltd | Real estate | 2018 |
| Crepe Cuisine Cornwall Ltd | Manufacturing | 2018 |
| CRG Consultants Ltd | Professional & scientific | 2020 |
| Crossfit Penzance Ltd | Arts & recreation | 2025 |
| Crossroads Garage (UK) Limited | Wholesale & retail | 2009 |
| Crown Goldsithney Ltd | Hospitality | 2023 |
| Crystal Clear Professional Cleaning Limited | Other services | 2014 |
| CVC Cornwall 2013 Ltd | Professional & scientific | 2013 |
| D Law Scaffolding Ltd | Construction | 2018 |
| D Semmens Construction Limited | Construction | 2025 |
| D W Cladding Ltd | Construction | 2017 |
| D.J. Keeler & SON Limited | Construction | 2003 |
| Daijyo V Limited | Wholesale & retail | 2020 |
| Dainton Medical Services Limited | Health & social care | 2016 |
| Daisies and Driftwood Childcare Group Ltd | Health & social care | 2026 |
| Dandelion - Disability Care Agency Ltd | Health & social care | 2023 |
| Daniel Sell Building Limited | Construction | 2017 |
| Daninosuk Ltd | Hospitality | 2025 |
| Darren and Claire Property Limited | Households | 2026 |
| Darroch Accountancy Limited | Professional & scientific | 2009 |
| Darroch Remedial Inspections Limited | Professional & scientific | 2012 |
| Datamode Systems Limited | Professional & scientific | 2002 |
| Daur Productions Ltd | Arts & recreation | 2024 |
| Davey & Gilbert Holdings Limited | Financial services | 2018 |
| Davey & Gilbert Limited | Construction | 2003 |
| Davey & Gilbert M&E Ltd | Construction | 2020 |
| Davey & Gilbert Mechanical Limited | Construction | 2013 |
| Davey & Gilbert Property Limited | Other services | 2018 |
| David Charles Laity Limited | Extraterritorial | 2025 |
| Davidmankinart Ltd | Arts & recreation | 2026 |
| Deats Cdes LLP | | 2014 |
| Decades Travel Limited | Administrative & support | 2025 |
| Denison James Limited | Information & communication | 1999 |
| DEP23 Catering Ltd | Hospitality | 2025 |
| Devenish Trading Limited | Wholesale & retail | 2007 |
| Dexzone Developments Ltd | Construction | 2024 |
| Dialled in Coffee Roasters Ltd | Manufacturing | 2024 |
| Digital Fabrications Limited | Manufacturing | 2013 |
| Dilbey Limited | Households | 1986 |
| DJT GAS Services Ltd | Construction | 2023 |
| DJT Management Services Ltd. | Real estate | 2011 |
| DK Communications Ltd | Professional & scientific | 2020 |
| DL Autos South West Ltd | Wholesale & retail | 2025 |
| DLW Housekeeping Limited | Administrative & support | 2019 |
| Doctors Fields Limited | Real estate | 2019 |
| Dolphin Stairlifts Cornwall Limited | Wholesale & retail | 2001 |
| Dormant Company 09887016 Limited | Extraterritorial | 2015 |
| Doughty Biggs PUB Co Ltd | Hospitality | 2024 |
| DR Hann Dermatologist Ltd | Hospitality | 2019 |
| DR JOE Curry Limited | Health & social care | 2009 |
| DR Pascale DU PRE Limited | Health & social care | 2019 |
| Drafted by Design Limited | Professional & scientific | 2016 |
| Drbs Cornwall Ltd | Construction | 2025 |
| Drbs Properties Limited | Construction | 2026 |
| Drive Elec Cars Limited | Extraterritorial | 2023 |
| DS4U Limited | Wholesale & retail | 1997 |
| Dteo Limited | Information & communication | 2008 |
| Dtkm Ltd | Hospitality | 2013 |
| Duchy Collective CIC | Health & social care | 2025 |
| Duchy Estates Limited | Real estate | 1977 |
| Duchy Fish Quota Company | Agriculture & fishing | 2001 |
| Duchy Management Company Limited | Real estate | 1999 |
| Dugdales Electrical Limited | Construction | 2024 |
| Dugewe Limited | Hospitality | 2022 |
| Duja Elite Ltd | Agriculture & fishing | 2025 |