| Cargo Trans Ltd | Transport & logistics | 2021 |
| Cargoman Transport&Services Ltd | Transport & logistics | 2013 |
| Carhub Newport Ltd | Wholesale & retail | 2022 |
| Cariad Dating Ltd | Other services | 2018 |
| Caribbean Twist Ltd | Hospitality | 2019 |
| Caribeatz-Meno Ltd | Education | 2025 |
| Caricare Ltd | Health & social care | 2025 |
| Carini Holdings Limited | Administrative & support | 2003 |
| Carisbrooke Lettings Ltd | Real estate | 2017 |
| Carisbrooke Priory Trust Company Limited | Other services | 2008 |
| Carl Sheedy Limited | Real estate | 2025 |
| Carlton Building Solutions Ltd | Manufacturing | 2014 |
| Carlton Industries UK Ltd | Manufacturing | 2017 |
| Carly's Crafty Creations Ltd | Other services | 2023 |
| Carmarthen Accident Repair Centre Limited | Wholesale & retail | 2000 |
| Carmel Holdco Limited | Real estate | 2024 |
| Carnell Consult Ltd | Health & social care | 2016 |
| Carningli Scaffolding (2002) Limited | Construction | 2002 |
| Carol Joan Holdings Ltd | Financial services | 2025 |
| Carpenter & Cleaning Service Ltd | Construction | 2024 |
| Carpet Loom (Newport) Limited | Wholesale & retail | 2012 |
| Carpets ETC Limited | Wholesale & retail | 2022 |
| Carplay Plug Ltd | Wholesale & retail | 2025 |
| Carpo's Construction Ltd | Construction | 2017 |
| Carpoint UK Motor Company Limited | Wholesale & retail | 2019 |
| Carreg Design Ltd | Professional & scientific | 2013 |
| Carrie-Poppo Limited | Construction | 2021 |
| Carro's Automotive Services Limited | Wholesale & retail | 2020 |
| Carrot Top Bakery Limited | Manufacturing | 2021 |
| Cars Website Limited | Wholesale & retail | 2015 |
| Carson Mews Management Company Limited | Households | 2005 |
| Carson's Group Ltd | Health & social care | 2015 |
| Carsonlets Limited | Real estate | 2024 |
| Carsonliving Limited | Health & social care | 2026 |
| Carter Mews (IOW) Limited | Construction | 2021 |
| Carter Property Investment Ltd | Real estate | 2018 |
| Cartnova Ltd | Wholesale & retail | 2025 |
| Cartref Building Restoration Services Limited | Construction | 2006 |
| Cartref Home Improvements Ltd | Construction | 2023 |
| Cartwheelers Gymnastics Limited | Arts & recreation | 2023 |
| Cartwright & Co. (Fencing) Limited | | 1982 |
| Cartwright Crosbie LLP | | 2026 |
| Cartwright Gwalia Properties Limited | Real estate | 2013 |
| Caru Pets Services Ltd | Other services | 2026 |
| Caruana Properties Ltd | Households | 2025 |
| Casa and Plants Limited | Wholesale & retail | 2025 |
| Cascade Conversions (Holdings) Limited | Financial services | 2019 |
| Cascade Conversions Limited | Wholesale & retail | 2012 |
| Cash Management Solutions Limited | Professional & scientific | 2014 |
| Caspine Design Services Ltd | Professional & scientific | 2019 |
| Castaldo's Ltd | Financial services | 2014 |
| Castalia Holdings Limited | Extraterritorial | 2007 |
| Castan's Limited | Hospitality | 2013 |
| Castell Coch Golf Course Limited | Arts & recreation | 2009 |
| Castello Foods Ltd | Hospitality | 2026 |
| Castle Acre Associates Limited | Real estate | 2008 |
| Castle Bars Ltd | Hospitality | 2020 |
| Castle Developments (Midlands) Limited | Construction | 1985 |
| Castle House School Trust Limited | Education | 1980 |
| Castle Inn Pembrokeshire Limited | Hospitality | 2016 |
| Castle Keepsecurity (Newport) Ltd | Administrative & support | 2023 |
| Castle Mews Caerleon Management 1990 Limited | Households | 1991 |
| Castlebridge Homes Limited | Wholesale & retail | 1986 |
| Castlehold Lane Management Company Limited | Households | 2016 |
| Castleton Turf and Soil Suppliers Ltd | Agriculture & fishing | 1998 |
| Cat Happiness Limited | Wholesale & retail | 2004 |
| Cat Keenan Ltd | Information & communication | 2020 |
| Cataleya Beauty Ltd | Other services | 2019 |
| Catalyst Construction Surveyors Limited | Information & communication | 2015 |
| Catalyst Growth Partners Ltd | Professional & scientific | 2014 |
| Catalyst Strategic Partnerships Limited | Professional & scientific | 2026 |
| Catering Dynamics (Trading) Limited | Hospitality | 2024 |
| Catermate Services Limited | Administrative & support | 2018 |
| Cates Brothers Limited | Wholesale & retail | 2015 |
| Cathedral Chambers Investments Limited | Real estate | 2015 |
| Cathedral Court (Newport) Management Company Limited | Households | 1999 |
| Cathedral Court Flats (Newport) Limited | Households | 1993 |
| Cathedral Heights Limited | Households | 2026 |
| Cathedrals Exhibition Management Limited | Arts & recreation | 1990 |
| Catherines Bakery Limited | Wholesale & retail | 2003 |
| Catsai Vision Ltd | Health & social care | 2018 |
| Cattell Property Management Ltd | Real estate | 2022 |
| Caughley Clay Group Ltd | Professional & scientific | 2016 |
| Cautela Diamond Ltd | Administrative & support | 2007 |
| Cautela Holdings Limited | Real estate | 2009 |
| Cavacon Ltd | Professional & scientific | 2026 |
| Cavarey Ltd | Transport & logistics | 2022 |
| Cavms Limited | Education | 2004 |
| Cavsfa Limited | Arts & recreation | 2018 |
| Cay’S Cars Ltd | Other services | 2017 |
| Cazacu Logistics Ltd | Transport & logistics | 2019 |
| CB Testing & Inspection Limited | Professional & scientific | 2007 |
| CB Therapy Solutions Limited | Health & social care | 2013 |
| CB Trading Management Ltd | Hospitality | 2025 |
| Cbem-Uk Ltd | Professional & scientific | 2020 |
| Cbgaming CYF | Wholesale & retail | 2025 |
| CBK (NPT) Limited | Hospitality | 2019 |
| CBT Therapies Ltd | Health & social care | 2020 |
| CC Property Solutions Ltd | Construction | 2011 |
| CC Walford Limited | Agriculture & fishing | 2023 |