| Cacwn Ltd | Information & communication | 2017 |
| Caddy Holdings Bridgend Limited | Financial services | 2013 |
| Cadefray Limited | Extraterritorial | 2023 |
| Cadeshaw Limited | Extraterritorial | 2023 |
| Cadogan Catering Limited | Hospitality | 2019 |
| Cadw Conservation Limited | Extraterritorial | 2003 |
| Cadwyn Solutions Ltd | Information & communication | 2020 |
| Cafel Limited | Hospitality | 2022 |
| Cafn Ltd | Professional & scientific | 2014 |
| CAI (Aberkenfig) Limited | Hospitality | 2019 |
| CAI Trading Ltd | Hospitality | 2023 |
| Caicom Limited | Professional & scientific | 2009 |
| Caimason Roofing Ltd | Construction | 2023 |
| Calicut Ltd | Hospitality | 2025 |
| Call Ovilkw Ltd | Transport & logistics | 2021 |
| Callacre Limited | Extraterritorial | 2026 |
| Callbest Limited | Extraterritorial | 2024 |
| Calltone Limited | Wholesale & retail | 2025 |
| Callward Limited | Extraterritorial | 2026 |
| Calm Recycling Solutions Limited | Professional & scientific | 2007 |
| Calon HR and Resourcing Limited | Administrative & support | 2024 |
| Cambrian Car Care Holdings Ltd | Wholesale & retail | 2021 |
| Cambrian Car Care Limited | Wholesale & retail | 1982 |
| Camdem Properties Limited | Hospitality | 2020 |
| Camilla Elizabeth Anne Crumb Limited | Extraterritorial | 2024 |
| Camino Learning Collective Limited | Education | 2014 |
| Campbell Court Management Limited | Professional & scientific | 2003 |
| Camper Limited | Wholesale & retail | 2006 |
| Camplas Holdings Limited | Financial services | 2021 |
| Camprise Limited | Extraterritorial | 2026 |
| Candleston Financial Services Limited | Financial services | 2004 |
| Candy Click Studios Limited | Professional & scientific | 2023 |
| Candy Computers Limited | Other services | 2005 |
| Cani-Trail Events Ltd | Arts & recreation | 2025 |
| Canton Estates Limited | Real estate | 2006 |
| CAP Engineering Services Limited | Professional & scientific | 2022 |
| Capel Siriol Limited | Other services | 2017 |
| Capital Accountancy (South Wales) Ltd | Professional & scientific | 2019 |
| Capital Hydraulic Services Ltd | Construction | 2022 |
| Captain Morgan Consulting Limited | Professional & scientific | 2016 |
| Captain Protein Ltd | Wholesale & retail | 2025 |
| Car Paints Plus Limited | Wholesale & retail | 2000 |
| Caradog Limited | Construction | 2020 |
| Card Crew Limited | Wholesale & retail | 2015 |
| Cardboard Playhouse Ltd | Wholesale & retail | 2025 |
| Cardiff & Vale Enterprise International Limited | Professional & scientific | 2000 |
| Cardiff Dough and Co Ltd | Information & communication | 2019 |
| Cardiff Nail and Beauty Training School Limited | Other services | 2018 |
| Cardiff Paediatrics Limited | Health & social care | 2012 |
| Care Angel Homes Limited | Health & social care | 2009 |
| Care Leavers Collective Community Interest Company | Education | 2026 |
| CARE4HEAT Limited | Construction | 2003 |
| Career Collective Group Ltd | Administrative & support | 2020 |
| Carey Clinical Limited | Health & social care | 2025 |
| Cariad Campers Limited | Transport & logistics | 2014 |
| Cariad Drums Ltd | Wholesale & retail | 2025 |
| Caring Companions Limited | Health & social care | 2005 |
| Carl Kjelsensvei 45 Ltd | Administrative & support | 2007 |
| Carn Carpentry Ltd | Construction | 2026 |
| Carn Rovers | Education | 2018 |
| Carousel Furniture Limited | Professional & scientific | 1981 |
| Carpenter Property Services Ltd | Real estate | 2018 |
| Carreg Builders Limited | Construction | 2019 |
| Carter Sustainable Construction Limited | Construction | 2020 |
| Carvano Ltd | Wholesale & retail | 2023 |
| Carwyn Jones Limited | Professional & scientific | 2021 |
| Case Amusements Limited | Arts & recreation | 2024 |
| Case Capital Limited | Professional & scientific | 2025 |
| Case Concepts Limited | Professional & scientific | 1995 |
| Caseley Performance Limited | Arts & recreation | 2021 |
| Castbray Limited | Manufacturing | 2021 |
| Castedge Limited | Extraterritorial | 2025 |
| Castell Clyd Ltd | Water & waste | 2025 |
| Castell TŶ Grŵp Ltd | Real estate | 2026 |
| Casthart Limited | Extraterritorial | 2026 |
| Castpine Limited | Extraterritorial | 2026 |
| Catalyst Seventeen Ltd | Professional & scientific | 2024 |
| Cayford Homes Limited | Construction | 2014 |
| CB Medicals Limited | Health & social care | 2019 |
| CBL Software Ltd | Extraterritorial | 2025 |
| Cdbrealestate Ltd | Real estate | 2022 |
| Cder Limited | Financial services | 2024 |
| CDJ 2025 Ltd | Financial services | 2025 |
| CDN Housing & ALL Things Pretty Ltd | Wholesale & retail | 2025 |
| CDP Associates Limited | Financial services | 2003 |
| CDW Lettings Ltd | Real estate | 2024 |
| CE Manufacturing Limited | Manufacturing | 2025 |
| CE Sales Limited | Hospitality | 2025 |
| CEC Accountancy Limited | Professional & scientific | 2023 |
| Cedars Tearoom Ltd | Hospitality | 2015 |
| Ceejay Landscapes Limited | Administrative & support | 2001 |
| Ceejay Pubs Ltd | Hospitality | 2019 |
| Cefn Cribwr Athletic Club Ltd | Arts & recreation | 2011 |
| Cefn Cribwr F.C. Limited | Education | 2020 |
| Celebrity Motion Products Ltd | Wholesale & retail | 2017 |
| Celestra Wealth Limited | Financial services | 2025 |
| Celteco Ltd | Construction | 2019 |
| Celtic Bouncy Castles Ltd | Arts & recreation | 2022 |
| Celtic Canopy Ltd | Administrative & support | 2026 |
| Celtic Carpentry & Home Improvements Ltd | Construction | 2023 |