| Colloquy Group Limited | Professional & scientific | 2021 |
| Colourfield Properties Limited | Real estate | 1998 |
| Colours United Limited | Hospitality | 2023 |
| Colyn Investments Ltd | Real estate | 2020 |
| Commercial Investment Limited | Extraterritorial | 1997 |
| Community Care Experts Ltd | Professional & scientific | 2020 |
| Community Climbing Ltd | Arts & recreation | 2026 |
| Companion Services Ltd | Wholesale & retail | 2016 |
| Companythree Ltd | Real estate | 2012 |
| Compelling Culture Ltd | Professional & scientific | 2020 |
| Compertum Consulting Ltd | Information & communication | 2020 |
| Complete Ecology Limited | Administrative & support | 1996 |
| Complete Hygiene Ltd. | Construction | 2012 |
| Conceptualeyes Limited | Information & communication | 2004 |
| Conessence Ltd | Construction | 2022 |
| Conference Craft Limited | Arts & recreation | 1982 |
| Congrove Management Company Limited | Real estate | 1988 |
| Conifer Management Company Limited | Households | 1980 |
| Conlon Templating Limited | Professional & scientific | 2017 |
| Connaught House (Surbiton) Limited | Real estate | 2008 |
| CONNECT4LESS Limited | Information & communication | 2025 |
| Connecting the Senses C.I.C. | Education | 2026 |
| Connectlane Ltd | Professional & scientific | 2023 |
| Connoisseur Mortgages LLP | | 2006 |
| Conseilukvisa Ltd. | Professional & scientific | 2022 |
| Consido Ltd | Professional & scientific | 2025 |
| Consistudy Limited | Information & communication | 2025 |
| Consort Lodge Management Limited | Households | 1993 |
| Constarch Limited | Administrative & support | 2017 |
| Construction Bear Limited | Construction | 2018 |
| Constructpro Supplies Limited | Construction | 2024 |
| Consub Limited | Professional & scientific | 2005 |
| Consub Property Investments Limited | Real estate | 2019 |
| Contact JO Ltd | Administrative & support | 2020 |
| Conversation TV Limited | Information & communication | 2014 |
| Cookease Ltd | Hospitality | 2011 |
| Cool Britannia Developments Ltd | Real estate | 2019 |
| Cool Cafe (Surbiton) Limited | Hospitality | 2022 |
| Cool Down Club Ltd | Hospitality | 2025 |
| Coombe Constructions Limited | Construction | 1969 |
| Coral Cove Strategies Ltd | Information & communication | 2011 |
| Coralie Scribbles Ltd | Information & communication | 2019 |
| Corely Group Ltd | Other services | 2022 |
| Corin Investments Ltd | Real estate | 2023 |
| Cork Coat Ltd | Construction | 2024 |
| Cornerstone Capital Partners Limited | Professional & scientific | 2009 |
| Cornerstone HR Consulting Limited | Professional & scientific | 2015 |
| Corpserv Ltd | Real estate | 2020 |
| Cosmopolitan 99 Ltd | Construction | 2019 |
| Cost Consulting International (UK) Ltd | Professional & scientific | 2007 |
| Cosy Homes Property Maintenance Ltd | Construction | 2021 |
| Count on ME Ltd | Education | 2025 |
| Covert Venture Partners Holdings Limited | Financial services | 2020 |
| Covert Venture Partners Limited | Information & communication | 2020 |
| CP Lighting Limited | Wholesale & retail | 2000 |
| CPA Property & Management Ltd | Real estate | 2015 |
| CPC Battery Services Limited | Wholesale & retail | 1982 |
| Cpldnconsulting Limited | Wholesale & retail | 2024 |
| CPM Waterproofing Services Limited | Construction | 2013 |
| CQV Tax Rebates Ltd | Information & communication | 2009 |
| Craggy Island Ltd | Arts & recreation | 2003 |
| Cranbourne Court (Walton-On-Thames) Management Limited | Households | 2003 |
| Cranebrook Company Limited | Households | 1990 |
| Cranes Park Ltd | Real estate | 2025 |
| Cranes Property Limited | Real estate | 2023 |
| Create 58 Ltd | Information & communication | 2015 |
| Create Pearls Limited | Information & communication | 2019 |
| Creationz Limited | Wholesale & retail | 2020 |
| Creative Coastal Living Limited | Real estate | 2025 |
| Creative London Limited | Real estate | 2006 |
| Creative Space Media Ltd | Administrative & support | 2021 |
| Creditor Tax Assessments Ltd | Information & communication | 2014 |
| Creditor Tax Filings Ltd | Information & communication | 2002 |
| Creditor Tax Rebates Ltd | Information & communication | 2009 |
| Cree Property Investments Ltd | Real estate | 2017 |
| Creedence Surbiton Limited | Households | 2020 |
| Creston Supply Ltd | Wholesale & retail | 2026 |
| Crewdson Road Properties Limited | Extraterritorial | 2012 |
| Crimefix International Ltd | Public administration | 2019 |
| Criston Property Services Limited | Real estate | 1993 |
| Cromwell Court (Kingston) Limited | Hospitality | 1988 |
| Cromwell Place Management Limited | Administrative & support | 2002 |
| Crotus Limited | Wholesale & retail | 2025 |
| Crowdserve Ltd | Wholesale & retail | 2021 |
| Crown Blue Line Limited | Other services | 1969 |
| Crown Court (Surbiton) Residents Association Limited | Households | 1963 |
| Crown Holidays Limited | Administrative & support | 1983 |
| Crown Travel Limited | Administrative & support | 1987 |
| Cruise London Limited | Transport & logistics | 2007 |
| Crypto Key Limited | Financial services | 2018 |
| Crystal Decor Limited | Construction | 2010 |
| CSS Contracts Ltd | Construction | 2011 |
| CTC Surbiton Limited | Wholesale & retail | 2026 |
| Cubo Design Ltd | Professional & scientific | 2010 |
| Cuffe Construction Limited | Construction | 2012 |
| Cuffe Holdings Limited | Real estate | 2002 |
| Cuffe Holdings NO 1 Ltd | Financial services | 2022 |
| Cuffe Holdings NO 2 Ltd | Financial services | 2022 |
| Cuffe PLC | Construction | 1991 |
| Culham Economics Ltd | Professional & scientific | 2018 |