| Clark Construction (South) Limited | Construction | 2022 |
| Classic Beauty Limited | Other services | 2003 |
| Classic Grounds Maintenance Ltd | Administrative & support | 2024 |
| Classic Traveller Journeys Limited | Administrative & support | 2011 |
| Clay Pigeon Kart Club Limited | Arts & recreation | 1983 |
| Clbs Dorset Limited | Construction | 2022 |
| Clbs Kitchens and Bathrooms Ltd | Construction | 2026 |
| Clearmount Court Management Co Limited | Hospitality | 1987 |
| Cleay Design Limited | Professional & scientific | 2013 |
| Clenston Trustees NO 1 Limited | Extraterritorial | 2020 |
| Clenston Trustees NO 2 Limited | Extraterritorial | 2020 |
| Clevedale Consulting Limited | Financial services | 2018 |
| Cleveland House (Chilworth) Limited | Real estate | 2013 |
| Clever Structures Ltd | Construction | 2022 |
| Cliff House Apartments (Southbourne) Ltd | Households | 2026 |
| Clifton Developers Ltd | Construction | 2023 |
| Clifton Hotel Development Limited | Real estate | 2018 |
| Climate Specialist Limited | Manufacturing | 2024 |
| Clinical Expert Management Ltd | Professional & scientific | 2003 |
| Clinical Skincare Solutions Ltd | Health & social care | 2022 |
| Clipper CG Holdings Limited | Financial services | 2016 |
| Clipper Contracting Group Ltd | Professional & scientific | 2008 |
| Clipper Drive Limited | Professional & scientific | 2020 |
| Clive Smith Skip Hire Limited | Water & waste | 2003 |
| Clockwork Consultancy Services Ltd | Professional & scientific | 2023 |
| Clockwork Limited | Water & waste | 1995 |
| Cloud Accountancy Services (UK) Limited | Professional & scientific | 2014 |
| Cloud Services Technology Ltd | Information & communication | 2018 |
| Cloudhill Productions Ltd | Information & communication | 2016 |
| CLP Secretaries (Southern) Limited | Administrative & support | 2006 |
| Clyffe House Flat Management Limited | Households | 1986 |
| Clyffe Sewerage Management Limited | Water & waste | 2014 |
| CMB Electrical Services Dorset Limited | Construction | 2020 |
| CNH Enterprises Limited | Administrative & support | 2013 |
| Coastal & Rural Properties Limited | Hospitality | 2014 |
| Coastal Barbarians Rowing Club CIC | Arts & recreation | 2023 |
| Coastal Rowing Centre Limited | Arts & recreation | 2012 |
| Coats Bros.Limited | Construction | 1956 |
| Cobb Farming Limited | Agriculture & fishing | 2016 |
| Cobra MDS Limited | Extraterritorial | 2016 |
| Cocoagogo Ltd | Hospitality | 2016 |
| Coelho & Edwardes Construction Ltd | Construction | 2024 |
| Coffee First (Exeter) Ltd | Wholesale & retail | 2020 |
| Cofrad UK Ltd | Professional & scientific | 2010 |
| Cogley Ltd | Administrative & support | 2003 |
| Cognitive Bias Solutions Limited | Administrative & support | 2016 |
| Cohen HK Ltd | Hospitality | 2019 |
| Cohiba Cafe Bar Limited | Hospitality | 2017 |
| Colby Plumbing & Heating Limited | Construction | 2017 |
| Coles Hospitality Limited | Hospitality | 2019 |
| Colin Clark and Sons Limited | Wholesale & retail | 1975 |
| Collins Consultancy & Training Limited | Administrative & support | 2016 |
| Collins Nets DC Ltd | Manufacturing | 2021 |
| Collins Nets Holdings Limited | Financial services | 2013 |
| Collins Nets Limited | Manufacturing | 2003 |
| Colliton Club Limited | Hospitality | 2013 |
| Colombia Direct Limited | Wholesale & retail | 2008 |
| Colortec Limited | Wholesale & retail | 2017 |
| Colour Luxe Ltd | Other services | 2022 |
| Common Ground | Administrative & support | 1982 |
| Community Association of Poundbury CIC | Wholesale & retail | 2025 |
| Community Share Wellness CIC | Health & social care | 2021 |
| Compass AI Limited | Information & communication | 2025 |
| Compass South (Weymouth) Limited | Households | 1968 |
| Complete Elevator Solutions Ltd | Manufacturing | 2022 |
| Compton Lodge Management Company Limited | Households | 1993 |
| Compton Marbling Limited | Wholesale & retail | 2018 |
| Computer Aide Limited | Information & communication | 2006 |
| Concept Creations Ltd | Construction | 2019 |
| Concorde Flooring & Ceilings Limited | Construction | 1973 |
| Concordiam Limited | Financial services | 2026 |
| Conexus Core Limited | Administrative & support | 2025 |
| Conibear Consultancy Limited | Professional & scientific | 2017 |
| Coningsby Place Management Company Limited | Households | 2018 |
| Conservatories of Dorchester Ltd | Construction | 2007 |
| Constantium Financial Solutions Limited | Financial services | 2020 |
| Contact Consulting (UK) Limited | Professional & scientific | 2003 |
| Convivial Rabbit Ltd | Hospitality | 2025 |
| Coombe Down Orchards Limited | Manufacturing | 2019 |
| Cooper & Cooper Electrical South Limited | Construction | 2019 |
| Coppard Developments Ltd | Construction | 2013 |
| Copper Street Investments Limited | Manufacturing | 2020 |
| Coram Tower RTM Company Limited | Households | 2012 |
| Core Plumbing Heating & GAS Ltd | Construction | 2023 |
| Cornerbay Limited | Information & communication | 1989 |
| Corporate Recovery Specialists Limited | Professional & scientific | 2007 |
| Corscombe Close (Block 8) Weymouth RTM Company Limited | Real estate | 2011 |
| Corscombe Close Block 4 RTM Company Limited | Real estate | 2011 |
| Corscombe Close Estate Management Company Limited | Households | 2024 |
| Corston House Management Company Limited | Real estate | 2013 |
| Country Cars Limited | Wholesale & retail | 1999 |
| Country Clearance Ltd | Water & waste | 2020 |
| Country Crafts Dorset Ltd | Wholesale & retail | 2025 |
| Country Office Furniture Ltd | Wholesale & retail | 2016 |
| Countryside Scaffolding Limited | Construction | 2015 |
| Countryview Surveyors Limited | Professional & scientific | 2022 |
| Countrywide Solar Limited | Construction | 2010 |
| County Office Business | | 1989 |
| Courtside Management Company (Weymouth) Limited | Households | 2016 |
| COWS2MILK Ltd | Agriculture & fishing | 2002 |