| C&A J Developments Limited | Administrative & support | 2025 |
| C&C Property Renovations Ltd | Construction | 2024 |
| C&C UK Group Limited | Wholesale & retail | 2021 |
| C&E Global Group Ltd | Administrative & support | 2016 |
| C&F Industrial Services Limited | Manufacturing | 2023 |
| C&G Car Sales Limited | Wholesale & retail | 2022 |
| C&G Property Development Services Ltd | Real estate | 2024 |
| C&J Frame Ltd | Construction | 2026 |
| C&N the Sced Limited | Hospitality | 2026 |
| C&R Metal Recycling Ltd | Wholesale & retail | 2025 |
| C&S (Swansea) Limited | Hospitality | 2019 |
| C&S Gilligan Ltd | Wholesale & retail | 2022 |
| C&S Thomas Properties Ltd | Real estate | 2026 |
| C&Z Solutions Ltd | Wholesale & retail | 2018 |
| C-Let Food Ltd | Hospitality | 2026 |
| C. & G. Tool & Cutter Co. Limited | Manufacturing | 1975 |
| C. & P. Control Panel Services Ltd | Manufacturing | 2023 |
| C. & P. Engineering Services Limited | Manufacturing | 1973 |
| C. & P. Group Holdings Limited | Financial services | 2018 |
| C. & P. Training Services Limited | Professional & scientific | 2018 |
| C. H. Enviromental Services Limited | Professional & scientific | 2018 |
| C.A. Roberts Builders Ltd | Construction | 2016 |
| C.E.M. Day Limited | Wholesale & retail | 1926 |
| C.E.O Nursery Ltd | Health & social care | 2017 |
| C.G. Toft (Leaded Lights) Limited | Construction | 1984 |
| C.H.E.S Ltd | Energy | 2014 |
| C.J. & E.J. Limited | Hospitality | 2006 |
| C.Jay Will Ltd | Transport & logistics | 2025 |
| C.M Hopkin & SON Ltd | Other services | 2019 |
| C.M.E. (Developments) Limited | Construction | 1987 |
| C.P.G. (Wales) Limited | Wholesale & retail | 1985 |
| C.T. Home Improvements & Freight Transport Ltd | Manufacturing | 2021 |
| C.T.A Properties Limited | Real estate | 2014 |
| C2C Construction Ltd | Construction | 2012 |
| C3 Centre for Creativity and Culture CIC | Information & communication | 2024 |
| Cabanban Company Limited | Administrative & support | 2021 |
| Cable Telecoms Limited | Information & communication | 2006 |
| Cabledox Solutions Ltd | Information & communication | 2026 |
| Cableplough Ltd | Extraterritorial | 2016 |
| Cabs Industrial Ltd | Construction | 2018 |
| Cabs Property Limited | Real estate | 2024 |
| Cabs Refurbishment Ltd | Construction | 2018 |
| Cabs Repairs Ltd | Construction | 2018 |
| Cabtured Limited | Arts & recreation | 2015 |
| Cader Limited | Real estate | 2001 |
| Cadog Homecare Ltd | Health & social care | 2011 |
| Cadog Limited | Hospitality | 2013 |
| Cadoxton Ground Rents Limited | Real estate | 2021 |
| Cadre Management Ltd | Hospitality | 2024 |
| Cadwalladr Cymru CIC | Education | 2026 |
| CAE Felin CSA CIC | Agriculture & fishing | 2021 |
| CAE Glas Camping Limited | Hospitality | 2025 |
| CAE TAN CSA C.I.C. | Agriculture & fishing | 2015 |
| CAE William Sports Company Limited | Arts & recreation | 1997 |
| Caebricks Developments Limited | Construction | 2003 |
| Caer LAS Trading Limited | Wholesale & retail | 2015 |
| Caer ST Convenience Store Ltd | Wholesale & retail | 2022 |
| Caerbont Automotive Instruments Limited | Manufacturing | 1993 |
| Caerphilly Developments SPV 1 Ltd | Construction | 2022 |
| Cafe Jaxx Ltd | Administrative & support | 2023 |
| Cafe Zoot Limited | Hospitality | 2001 |
| Caht Property Holdings Ltd | Real estate | 2020 |
| Caimason Building Services Ltd | Construction | 2024 |
| Caisley Family Estates Limited | Construction | 2021 |
| Caistec Limited | Information & communication | 2023 |
| Caitlin Evelyn Limited | Administrative & support | 2012 |
| Cajb Properties Ltd | Real estate | 2016 |
| Cakes From Wales Limited | Manufacturing | 2006 |
| Cakeylicious Ltd | Extraterritorial | 2025 |
| CAL Accountancy Limited | Professional & scientific | 2013 |
| Calcutt Cafes Limited | Wholesale & retail | 2004 |
| Calcutt Cafes Trustees Limited | Other services | 2025 |
| Caldey Island Tea Gardens Ltd | Hospitality | 2021 |
| Calibion Ltd | Agriculture & fishing | 2018 |
| California Penlan Limited | Hospitality | 2026 |
| Callatis Limited | Hospitality | 2022 |
| Callday Limited | Professional & scientific | 1999 |
| Called to Care Companionship Ltd | Health & social care | 2025 |
| Calls Direct Communications Ltd | Administrative & support | 2011 |
| Callum Davies Properties Ltd | Real estate | 2021 |
| Callum Thomas Consulting Ltd | Professional & scientific | 2025 |
| Callum Wheeler Consultancy Ltd | Health & social care | 2021 |
| Calm Movers CIC | Arts & recreation | 2026 |
| Calmness in Chaos Ltd | Health & social care | 2025 |
| Calon Adhd Project-Cap CIC | Other services | 2021 |
| Calon Cardio-Technology Ltd | Professional & scientific | 2007 |
| Calon Construction Ltd | Construction | 2014 |
| Calon Fawr Nursing Home Limited | Health & social care | 2003 |
| Calon Llanelli Ltd | Administrative & support | 2011 |
| Calpe Investments Limited | Real estate | 2003 |
| CAM Sport Limited | Wholesale & retail | 2010 |
| Cambria Financial Ltd | Financial services | 2013 |
| Cambria Metals CYF | Manufacturing | 2024 |
| Cambrian Castings (Wales) Limited | Manufacturing | 2000 |
| Cambrian Catering Services Limited | Extraterritorial | 2014 |
| Cambrian Engineering Industries Limited | Real estate | 1935 |
| Cambrian Flying Club Ltd | Other services | 2005 |
| Cambrian House Limited | Construction | 2021 |
| Cambrian Housing Company Limited | Real estate | 2007 |
| Cambrian Refrigeration Limited | Energy | 2010 |