| Cullen Property (Branksome Park) Limited | Construction | 2024 |
| Cullen Property (Canford Cliffs) Limited | Construction | 2024 |
| Cullen Property Group Limited | Construction | 2014 |
| Cultivate Innovate Ltd | Professional & scientific | 2024 |
| Cultura Connect Consultancy Ltd | Professional & scientific | 2025 |
| Cultural Diagnostics Ltd | Health & social care | 2016 |
| Cumberland Reinforcements Limited | Manufacturing | 1983 |
| Cumnor Road Limited | Households | 2019 |
| Cunningham Aero Ltd. | Administrative & support | 2002 |
| Cupe International Limited | Professional & scientific | 2014 |
| Cuppa Crew Ltd | Hospitality | 2021 |
| Cuppa Limited | Wholesale & retail | 2015 |
| Cura Haircare LP | | 2024 |
| Curabit Limited | Other services | 2022 |
| Curated Cottages Ltd | Administrative & support | 2025 |
| Curated ROW Ltd | Wholesale & retail | 2025 |
| Curis Advisory Limited | Professional & scientific | 2021 |
| Curly Bracket Media Ltd | Information & communication | 2022 |
| Current Context Limited | Professional & scientific | 2025 |
| Curtains Fabrics and Upholstery Limited | Manufacturing | 2025 |
| Curuk Ltd | Other services | 2019 |
| Curvin Transport (Poole) Limited | Transport & logistics | 2011 |
| Custom Covers Marine Upholstery Ltd | Administrative & support | 2011 |
| Custom Fit Furniture Ltd | Manufacturing | 2016 |
| Custom Fitting Solutions Ltd | Construction | 2019 |
| Custom Made Furniture Limited | Manufacturing | 2005 |
| Customate (Southern) Ltd | Wholesale & retail | 2018 |
| Customtek Coatings Limited | Construction | 2014 |
| Cute Stickers Only Limited | Wholesale & retail | 2025 |
| Cuthbury Construction Ltd | Construction | 2015 |
| Cuthbury Insulations Limited | Construction | 2023 |
| Cuthbury Roofing Ltd | Construction | 2022 |
| Cuthbury Wimborne Ltd | Construction | 2022 |
| Cutler Electrical & Controls Ltd | Manufacturing | 2025 |
| Cutsy Limited | Manufacturing | 2017 |
| Cutting Edge Health Limited | Health & social care | 2022 |
| CV Research Ltd | Professional & scientific | 2014 |
| Cvcr Limited | Extraterritorial | 2021 |
| CVD Health Limited | Financial services | 2022 |
| Cvedo Ltd | Information & communication | 2026 |
| Cvrt Parts Ltd | Public administration | 2018 |
| CW Concepts Ltd | Construction | 2018 |
| Cway Group Limited | Wholesale & retail | 2025 |
| CWI Education Ltd | Education | 2024 |
| CY Services Ltd | Information & communication | 2017 |
| Cybel Ltd | Professional & scientific | 2025 |
| Cyber GTM Limited | Information & communication | 2025 |
| Cyber Security Sales Limited | Information & communication | 2023 |
| Cyber Seren Limited | Information & communication | 2026 |
| Cyber-Scope Ltd | Information & communication | 2025 |
| Cybervista Tech Limited | Information & communication | 2024 |
| Cyclefix (Christchurch) Limited | Wholesale & retail | 2019 |
| Cyclefix (Poole) Limited | Wholesale & retail | 2021 |
| Cynapse Ltd | Professional & scientific | 2015 |
| Cypher Information Technology Limited | Information & communication | 2001 |
| Cypia Limited | Wholesale & retail | 2024 |
| Cyrgdropshipping Ltd | Wholesale & retail | 2026 |
| Czechia United LK Ltd | Professional & scientific | 2025 |
| Córdoba Music Group Ltd. | Wholesale & retail | 2021 |
| D & D Ocean Developments Limited | Administrative & support | 2004 |
| D & G Morgan Ltd | Construction | 2004 |
| D & H Stone Holdings Ltd | Financial services | 2018 |
| D & J Developments (Bournemouth) Limited | Construction | 2000 |
| D & J Mechanical Services Ltd | Construction | 2017 |
| D & L Barbers Ltd | Other services | 2023 |
| D & L Haulage (Dorset) Ltd | Wholesale & retail | 2008 |
| D & N Brickwork and Property Maintenance Ltd | Construction | 2019 |
| D & P Facilities Ltd | Other services | 2016 |
| D B Animals Limited | Wholesale & retail | 2006 |
| D B Engineering (Dorset) Limited | Manufacturing | 2009 |
| D B Foods (Holdings) Limited | Professional & scientific | 2008 |
| D C Ceilings and Partitions Limited | Construction | 2016 |
| D F Plant Hire Ltd | Construction | 2014 |
| D F Plastering Ltd | Construction | 2018 |
| D G Etali Limited | Health & social care | 2011 |
| D I Constructions Limited | Construction | 2018 |
| D J Q R Limited | Other services | 2016 |
| D J York Limited | Construction | 2007 |
| D K Eastment Groundworks Ltd | Construction | 2014 |
| D Landen Properties Ltd | Real estate | 2026 |
| D Mosley Limited | Administrative & support | 2005 |
| D P Facility Management Ltd | Professional & scientific | 2015 |
| D R Contractors Ltd | Construction | 2014 |
| D R G R Limited | Financial services | 2000 |
| D S Callards Limited | Information & communication | 1993 |
| D W Services Poole Ltd | Construction | 2026 |
| D&H Autos Limited | Wholesale & retail | 2011 |
| D&L Vehicle Maintenance Services Ltd | Extraterritorial | 2015 |
| D&M Technologies Limited | Information & communication | 2010 |
| D&O Scaffolding Ltd | Construction | 2026 |
| D&O South Coast Solar Ltd | Energy | 2023 |
| D&P Partners Limited | Real estate | 2013 |
| D&T Castle Ltd | Real estate | 2024 |
| D'Amour Ltd | Health & social care | 2022 |
| D-Gtal Digital Agence Ltd | Professional & scientific | 2025 |
| D. Blackmore Carpentry & Marine Ltd | Manufacturing | 2022 |
| D. P. Seals Limited | Manufacturing | 1962 |
| D.B Driveways Ltd | Construction | 2024 |
| D.B. Foods Limited | Wholesale & retail | 1992 |
| D.E.P. Subsea Solutions Limited | Other services | 2014 |