| Clevedon Pier and Heritage CIC | Arts & recreation | 1983 |
| Clevedon Plumbing Supplies Limited | Wholesale & retail | 2013 |
| Clevedon Pride CIC | Other services | 2011 |
| Clevedon Property Management Limited | Households | 2020 |
| Clevedon Railways Limited | Arts & recreation | 2013 |
| Clevedon Renovations Limited | Construction | 2025 |
| Clevedon RFC Trading and Supporters Group Limited | Arts & recreation | 2016 |
| Clevedon Sailing Club Ltd | Arts & recreation | 2019 |
| Clevedon Salerooms Limited | Wholesale & retail | 2006 |
| Clevedon Service Centre Ltd | Wholesale & retail | 2026 |
| Clevedon Transport Management Limited | Transport & logistics | 1976 |
| Clevedon UK Limited | Construction | 2009 |
| Clifton Chiropractic Clinic Limited | Health & social care | 2016 |
| Clifton Outdoor Kitchens Ltd | Construction | 2022 |
| Clifton Precious Metals Limited | Wholesale & retail | 2026 |
| Cloudy Robot Limited | Professional & scientific | 2013 |
| Clubdecks Limited | Wholesale & retail | 2025 |
| Clynder Consulting Limited | Professional & scientific | 2019 |
| CMS Property Group Ltd | Real estate | 2023 |
| CO2ZERO Livework Limited | Real estate | 2009 |
| CO2ZERO Wilder Street Management Company Limited | Households | 2021 |
| Coanda Limited | Other services | 2008 |
| Coastlord Property Management Limited | Households | 1984 |
| Cobalt Consultancy Ltd | Administrative & support | 2016 |
| Cobolt Limited | Information & communication | 2012 |
| Codes to Share Limited | Information & communication | 2018 |
| Coecreative Design Ltd | Professional & scientific | 2012 |
| Coleridge House Associates Limited | Information & communication | 2024 |
| Coleridge House Properties Limited | Real estate | 2023 |
| Coleridge Road (Flat Management) Limited | Households | 1973 |
| Coleridge Wealth Management Limited | Financial services | 2019 |
| Colin Thorne Bathrooms Ltd | Construction | 2020 |
| Colour Print Management Ltd | Manufacturing | 2002 |
| Colton Property Management Limited | Real estate | 2017 |
| Coly House Limited | Health & social care | 2008 |
| Combe Fields Portishead (Management) Limited | Households | 1981 |
| Combined Property Solutions Limited | Administrative & support | 2005 |
| Communicate Business Solutions Limited | Professional & scientific | 2000 |
| Connectra Global Limited | Professional & scientific | 1998 |
| Contract Hire (Clevedon) Limited | Administrative & support | 1990 |
| Conway Chapple & Co | | 1992 |
| Coombe Ventures Ltd | Construction | 2020 |
| Coopers Edge (Oak) Management Company Limited | Households | 2006 |
| Coppice Mews Limited | Households | 2002 |
| Core Drill Limited | Construction | 2018 |
| Core Drilling UK Limited | Construction | 2025 |
| Corner Sports Ltd | Wholesale & retail | 2025 |
| Corridors of Finance Ltd | Information & communication | 2025 |
| Cotswold Manor Cottage Limited | Real estate | 2024 |
| Cotswold Manor House Limited | Real estate | 2019 |
| Cotswold Spa House Limited | Real estate | 2021 |
| Courthouse Apartments Management Company Limited | Households | 1999 |
| Coveney Consulting Group Ltd | Extraterritorial | 2020 |
| Cowley Properties SW Ltd | Construction | 2025 |
| Coyne Wealth Limited | Construction | 2015 |
| Craft - Building Refined Ltd | Construction | 2021 |
| Crandell Limited | Wholesale & retail | 1985 |
| Crane Building Contractors Ltd | Construction | 2015 |
| Crayfish Limited | Real estate | 2000 |
| CRB 1 Limited | Extraterritorial | 2012 |
| Create Flavours Limited | Extraterritorial | 2023 |
| Creativemind Training Limited | Professional & scientific | 2022 |
| Crescendo Recordings Limited | Information & communication | 2025 |
| Crescere Property Limited | Real estate | 2025 |
| CRISIS3SIXTY Ltd | Information & communication | 2023 |
| Criterion Bathroom and Design Limited | Construction | 2024 |
| Criterion Plumbing and Heating Limited | Construction | 2024 |
| Criterion Renewables Limited | Construction | 2024 |
| Cromer Court (Clevedon) Management Company Limited | Households | 1997 |
| Croscombe Lodge Management Ltd | Households | 2023 |
| Crownreel Limited | Households | 2003 |
| CRU Films Limited | Information & communication | 2015 |
| CTR Security SW Ltd | Administrative & support | 2023 |
| Cult of Paint Limited | Wholesale & retail | 2020 |
| Currer Construction Limited | Construction | 2023 |
| Cushing Construction Ltd | Construction | 2020 |
| Custom Cable Labels Ltd | Manufacturing | 2022 |
| Custom Circuits Limited | Information & communication | 2011 |
| Custom House Court Management Limited | Households | 2016 |
| Custom Printed Limited | Wholesale & retail | 2021 |
| Custom Profiles Limited | Wholesale & retail | 2005 |
| Cvcosmos Ltd | Information & communication | 2020 |
| Cvma Limited | Arts & recreation | 2005 |
| Cvpo Limited | Wholesale & retail | 2015 |
| CW Removals & Storage SW Ltd | Transport & logistics | 2025 |
| CWM Group Limited | Financial services | 2023 |
| Cwrt Maes-Y-Llyn (Newport) Management Company Limited | Households | 2007 |
| Cyber Teknowledge Ltd | Information & communication | 2023 |
| D & K Groundworks Limited | Construction | 2012 |
| D James Carpentry & Building Limited | Construction | 2024 |
| D Jones Films and Television Ltd | Information & communication | 2014 |
| D&D Pubs Ltd | Hospitality | 2024 |
| D&S Partnership LLP | | 2022 |
| D&T Curnock Limited | Professional & scientific | 2022 |
| D-Tech Supplies Limited | Information & communication | 2024 |
| D2 (Swindon) Management Company Limited | Households | 2011 |
| DA Vinci Developments Limited | Construction | 2006 |
| Dali Care Ltd | Extraterritorial | 2024 |
| Damian Cooper Limited | Other services | 2013 |
| Danilo Shoots Ltd | Extraterritorial | 2025 |