| Cornwall Roofing Ltd | Construction | 2018 |
| Cornwall Self Catering Collective Limited | Other services | 2025 |
| Cornwall Soapbox (Falmouth) Ltd | Extraterritorial | 2018 |
| Cornwall Soapbox (Fore ST) Ltd | Manufacturing | 2018 |
| Cornwall Soapbox (ST Ives) Ltd | Extraterritorial | 2021 |
| Cornwall Soapbox Ltd | Manufacturing | 2015 |
| Cornwall Speech Therapy Limited | Health & social care | 2024 |
| Cornwall Trades Finder Ltd | Professional & scientific | 2026 |
| Cornwool Craftivista CIC | Education | 2018 |
| Coronatuslimited Ltd | Hospitality | 2025 |
| Cortenmetals Ltd | Professional & scientific | 2024 |
| Counting Shepherds Ltd | Professional & scientific | 2016 |
| Cousin Jacks Enterprises Limited | Administrative & support | 2008 |
| CR Building Ltd | Construction | 2023 |
| Crashburn Media Limited | Information & communication | 2010 |
| Cream Cornwall Limited | Wholesale & retail | 2016 |
| Create Cornwall (Construction) Limited | Construction | 2021 |
| Creative Signs Cornwall Limited | Professional & scientific | 2024 |
| Creek and Country Ltd | Hospitality | 2021 |
| Cremin Surfacing Groundworks & Landscaping Limited | Construction | 2015 |
| Cribbs Restaurants Limited | Hospitality | 2011 |
| Crouch Consultancy Services Limited | Professional & scientific | 2023 |
| Crystal Mings Limited | Hospitality | 2024 |
| CSB (Cornwall) Ltd | Real estate | 2024 |
| Cscape Dance CIC | Arts & recreation | 2014 |
| CSD Bars Ltd | Hospitality | 2025 |
| CTH Automotive Limited | Wholesale & retail | 2025 |
| Ctsl Developments Ltd | Real estate | 2017 |
| Cube Cornwall Limited | Construction | 2025 |
| Cube Office Limited | Wholesale & retail | 2009 |
| Cull Marshall Ltd | Financial services | 2003 |
| Culture Manual Ltd | Information & communication | 2022 |
| Culture Restaurant Ltd | Hospitality | 2022 |
| Curlew PR Limited | Professional & scientific | 2015 |
| Current Creative Ltd | Professional & scientific | 2025 |
| Curry Baba Falmouth Ltd | Hospitality | 2023 |
| Custom Quay Ltd | Real estate | 2022 |
| D Charles Construction Ltd | Construction | 2025 |
| D. L. Marine Limited | Manufacturing | 2008 |
| DAC Europe Limited | Professional & scientific | 2014 |
| Daisy V Limited | Financial services | 2019 |
| Dales of Falmouth Ltd | Financial services | 2018 |
| DAN Ball Window Cleaning Services Ltd | Administrative & support | 2022 |
| DAN DAN the Lobster MAN Ltd | Wholesale & retail | 2021 |
| Dana Young Limited | Wholesale & retail | 2010 |
| Danlock Garage Ltd | Wholesale & retail | 2025 |
| Dark Energy Ventures Limited | Professional & scientific | 2024 |
| Dark Pony Coffee Ltd | Hospitality | 2020 |
| Dashwood House Management Company Limited | Households | 1990 |
| Data Skytrack Limited | Wholesale & retail | 1999 |
| Datapunct Ltd | Information & communication | 2021 |
| David Medland Ltd | Financial services | 2018 |
| David Morris Contract Services Ltd | Construction | 2011 |
| Davies Drainage Solutions Ltd | Water & waste | 2022 |
| Davies Safety Solutions Ltd | Professional & scientific | 2026 |
| Ddraig R & L Ltd | Mining & quarrying | 2026 |
| Dean Stevens Wealth Management Ltd | Administrative & support | 2017 |
| Deejay Commercial Limited | Financial services | 2022 |
| Defacto Project Management Limited | Professional & scientific | 1996 |
| Deli Thai Limited | Hospitality | 2025 |
| Dent Hypotheses Ltd | Information & communication | 2022 |
| Dental Alchemy Ltd | Health & social care | 2013 |
| Dentanol Ltd | Extraterritorial | 2017 |
| Denyer Turner Marine LLP | | 2020 |
| Desmond & Co Estate Agents Limited | Real estate | 2017 |
| Devonshire House Management Company (Falmouth) Limited | Households | 1982 |
| Dgi-Uk Ltd | Administrative & support | 2019 |
| DHK Corporation Ltd | Health & social care | 2017 |
| DHR Falmouth Limited | Administrative & support | 2024 |
| Digital for ALL Consulting Ltd | Information & communication | 2022 |
| Discovery Quay Property Limited | Extraterritorial | 2006 |
| Discovery Quay Square Limited | Administrative & support | 2006 |
| Diveglobal Limited | Wholesale & retail | 2024 |
| Diveuk Ltd | Wholesale & retail | 2024 |
| DJA Property Ltd | Construction | 2026 |
| DNA Holdings Ltd | Real estate | 2023 |
| Dogbite Ltd | Information & communication | 2012 |
| Donwood Ltd | Hospitality | 2025 |
| DOS Padres LLP | | 2023 |
| DOT Accountancy Limited | Professional & scientific | 2024 |
| Dough an Dowr Limited | Hospitality | 2023 |
| Dough Selecta Limited | Hospitality | 2022 |
| Dovedale Digital Limited | Information & communication | 2024 |
| Downshiftclub Ltd | Administrative & support | 2025 |
| DR P R Jordan Ltd | Health & social care | 2019 |
| Dracaena Court Limited | Households | 2007 |
| Dreckly Threads Ltd | Wholesale & retail | 2025 |
| Duchy Cars Ltd | Transport & logistics | 2014 |
| Duchy Transport Services LLP | | 2014 |
| Duchy Ventures Ltd | Construction | 2019 |
| Duco Management Ltd | Real estate | 2025 |
| Dunes Property Ltd | Real estate | 2024 |
| DV7 Ltd | Hospitality | 2025 |
| DY10 Holdings Limited | Financial services | 2017 |
| DY10 Properties Limited | Real estate | 2019 |
| Dypan Properties Limited | Real estate | 1996 |
| DZK Estate Ltd | Real estate | 2024 |
| E Davidson Catering Limited | Hospitality | 2025 |
| E Southerden Woodwork Ltd | Manufacturing | 2019 |
| E7 Digital Limited | Professional & scientific | 2010 |