| CNS Dental Limited | Health & social care | 2023 |
| Coast 2 Coast Engineering Limited | Professional & scientific | 2018 |
| Coast to Moor Ltd | Administrative & support | 2023 |
| Coastal Connections (Cornwall) Limited | Manufacturing | 2025 |
| Coastline Campers Limited | Wholesale & retail | 2019 |
| Coastline Stays Cornwall Ltd | Hospitality | 2026 |
| Coffee Dylemma Newton Ltd | Hospitality | 2024 |
| Continuum Property Holdings Limited | Real estate | 2019 |
| Coombe Mill Homes Ltd | Households | 2002 |
| Corinne Dennis Cycle Clothing Ltd | Wholesale & retail | 2009 |
| Corisande Manor Management Company Limited | Households | 2014 |
| Cornerstone Materials Group Limited | Financial services | 2022 |
| Cornetworks Limited | Information & communication | 2009 |
| Cornish Accounting Solutions Limited | Professional & scientific | 2003 |
| Cornish Bookkeeping Ltd | Professional & scientific | 2021 |
| Cornish Cars Ltd | Other services | 2025 |
| Cornish Clothing Stores Ltd | Wholesale & retail | 2025 |
| Cornish Coast Adventures Ltd | Arts & recreation | 2010 |
| Cornish Couriers Ltd | Transport & logistics | 2026 |
| Cornish Estates Limited | Professional & scientific | 1980 |
| Cornish Hydrangeas Ltd | Agriculture & fishing | 2009 |
| Cornish Ice Clean Ltd | Administrative & support | 2025 |
| Cornish Lime Company Limited | Manufacturing | 2002 |
| Cornish Payroll Solutions Ltd | Extraterritorial | 2003 |
| Cornish Tipis Limited | Hospitality | 2021 |
| Cornish Traction Preservation Club Limited | Other services | 1998 |
| Cornwall Community Foundation | Other services | 2003 |
| Cornwall County Football Association Limited | Other services | 2000 |
| Cornwall Creative Ltd | Professional & scientific | 2010 |
| Cornwall Ex-Military Info and Welfare Hub C.I.C. | Health & social care | 2023 |
| Cornwall Flying Club Limited | Arts & recreation | 1978 |
| Cornwall Ideas Limited | Information & communication | 2016 |
| Cornwall Partners in Policymaking (SW) CIC | Health & social care | 2019 |
| Cornwall Plastic Recycling Ltd | Water & waste | 2019 |
| Cornwall Refrigerated Transport Services Limited | Manufacturing | 2002 |
| Cornwall Resins Ltd | Construction | 2024 |
| Cornwall Tile Studio Ltd | Manufacturing | 2019 |
| Cornwall Traffic Services Limited | Transport & logistics | 2003 |
| Cornwall Trophies Limited | Wholesale & retail | 2012 |
| Cornwall Workshops Limited Limited | Wholesale & retail | 2025 |
| Cortec Services Ltd | Construction | 2026 |
| Coyote Clothing Limited | Wholesale & retail | 2005 |
| Creative Darkroom Ltd | Arts & recreation | 2016 |
| Crinnis Wood Management Company Limited | Households | 2001 |
| Crocwell Wong Limited | Hospitality | 2024 |
| Croft Construction (SW) Limited | Construction | 2023 |
| Culverland Ltd | Extraterritorial | 2024 |
| Culverwood Properties Ltd | Real estate | 2025 |
| Curious Laboratories Ltd | Arts & recreation | 2018 |
| Custom Developments Limited | Construction | 2010 |
| Cwmboi Developments Ltd | Construction | 2018 |
| Cyriac TOR Limited | Manufacturing | 1997 |
| D a Thomas and SON Limited | Construction | 2005 |
| D&L Construction Cornwall Limited | Construction | 2019 |
| D&M Developments (UK) Ltd | Manufacturing | 2011 |
| D. H. Brown Limited | Extraterritorial | 2022 |
| D. R. Hopkins & Sons Limited | Hospitality | 1999 |
| DAD Property Ltd | Construction | 2022 |
| Daily Essentials Bodmin Ltd | Wholesale & retail | 2025 |
| DAN Jasper Carpentry & Construction Limited | Construction | 2019 |
| Dandre Management Company Limited | Households | 2002 |
| Dark Sky Alpacas Ltd | Agriculture & fishing | 2016 |
| Darren Harris Limited | Construction | 2019 |
| Darren Hawkes Landscapes Limited | Administrative & support | 2014 |
| Dave Wright Electrical Limited | Construction | 2003 |
| David Galvin Construction Limited | Construction | 2007 |
| Davidstow Airfield and Cornwall at WAR Museum Limited | Arts & recreation | 2007 |
| Dawson (Machinery) Ltd | Wholesale & retail | 2024 |
| Dazzle Clean Limited | Administrative & support | 2015 |
| DE Courcey House Management Company Limited | Households | 2019 |
| Defib Ready Limited | Information & communication | 2023 |
| Delimmar Limited | Manufacturing | 2026 |
| Delphy Pool Ltd | Arts & recreation | 2023 |
| Demelza Financial Planning Limited | Financial services | 2003 |
| Demelza Independent Estate Planning Limited | Professional & scientific | 2014 |
| Derek Cousens Limited | Professional & scientific | 2007 |
| Derek GOW Consultancy Ltd | Professional & scientific | 2003 |
| Deronia Limited | Construction | 2004 |
| Derow Property Ltd | Real estate | 2023 |
| Describe Language Services Ltd | Professional & scientific | 2019 |
| Design for Sport Developments Ltd | Manufacturing | 2009 |
| Design for Sport Limited | Professional & scientific | 2007 |
| DESIGN79 (UK) Limited | Manufacturing | 2011 |
| Devington Freeholders Ltd | Households | 2002 |
| Devington Hall Management Company Limited | Households | 1999 |
| Dewey’S Kitchen Ltd | Hospitality | 2024 |
| DH Building Maintenance Limited | Construction | 2015 |
| Diamond Cleaning SW Ltd | Administrative & support | 2017 |
| Dickson Group Holdings Limited | Financial services | 2023 |
| Dickson Mechanical Fasteners Limited | Financial services | 2023 |
| Dickson Property Holding Ltd | Construction | 2024 |
| Digit Info-Tec Ltd | Information & communication | 1996 |
| Digital Learner Ltd | Education | 2023 |
| Dingle Brothers Systems Limited | Information & communication | 1988 |
| Dingle Construction Ltd | Construction | 2018 |
| Diraro Ltd | Information & communication | 2003 |
| DISCOVERING42 CIC | Wholesale & retail | 2020 |
| Discreet Pest Control Cornwall Limited | Administrative & support | 2025 |
| DJ Housing Innovations Ltd | Real estate | 2025 |
| DK Hygienic Cladding Limited | Construction | 2008 |