| Collated Ltd | Wholesale & retail | 2018 |
| Collective Services Limited | Administrative & support | 2025 |
| Colors UK Limited | Wholesale & retail | 2007 |
| Colville Holdings Limited | Real estate | 2024 |
| Colvin Assured Limited | Wholesale & retail | 1974 |
| Coman Developments Ltd | Construction | 2024 |
| Coman Kitchens Ltd | Construction | 2021 |
| Comfort Group Holdings Ltd | Financial services | 2026 |
| Comfort Living Care Ltd | Health & social care | 2018 |
| Commonwealth Social Housing Company Ltd | Other services | 2023 |
| Community Action Guardians CIC | Health & social care | 2024 |
| Complete Electrical (GB) Ltd | Construction | 2008 |
| Complete Field Films Ltd | Information & communication | 2018 |
| Compliant Electrical Solutions Ltd | Construction | 2025 |
| Complisafe Limited | Professional & scientific | 2021 |
| Compound Good Ltd | Financial services | 2014 |
| Concrete SLP Limited | Professional & scientific | 2011 |
| Connectingsphere Ltd | Professional & scientific | 2026 |
| Conquer Technology Group Limited | Financial services | 2024 |
| Conquer Technology Ltd | Other services | 2023 |
| Conroy Builders (Croydon) Limited | Construction | 2009 |
| Conservative Friends of SRI Lanka Ltd | Other services | 2012 |
| Considerate Partners Ltd | Professional & scientific | 2018 |
| Consolidated Marketing Solutions Ltd | Wholesale & retail | 2025 |
| Consult Education Ltd | Education | 2014 |
| Consult Martial Limited | Professional & scientific | 2017 |
| Contact Builder Surrey Limited | Construction | 2023 |
| Contact Estate Agents Limited | Real estate | 2014 |
| Contact Estates Limited | Real estate | 2023 |
| Contractor Link Ltd | Administrative & support | 2023 |
| Coopers Court (Northfleet) Management Company Limited | Real estate | 2007 |
| Coplands Limited | Professional & scientific | 2025 |
| Core Consulting Information Technology Limited | Information & communication | 2022 |
| Corealign HR Ltd | Administrative & support | 2025 |
| Coriander Court Freehold Ltd | Households | 2025 |
| Cornerways Investments Limited | Real estate | 2008 |
| Coronet Estates Limited | Real estate | 2020 |
| COS Recruitment Services Ltd | Administrative & support | 2024 |
| Cosma Consulting Ltd | Information & communication | 2002 |
| Cosmetic Ceramics Ltd | Health & social care | 2005 |
| Costagliola CD Building and Construction Limited | Construction | 2026 |
| County Holdings (2018) Ltd | Financial services | 2018 |
| Coyne Brickworks Limited | Construction | 2004 |
| Cozee Stays Ltd | Hospitality | 2025 |
| CP Auto Service Center Ltd | Wholesale & retail | 2025 |
| CP Lettings Limited | Real estate | 2022 |
| CPA Commercial Services Limited | Wholesale & retail | 2010 |
| CPH Property Ltd | Real estate | 2019 |
| CR Technical Services Ltd | Construction | 2015 |
| CR0 Estate Agents Limited | Real estate | 2023 |
| CR2 Decoration Ltd | Wholesale & retail | 2026 |
| CR2 Properties London Ltd | Real estate | 2022 |
| CR2 Services Ltd | Administrative & support | 2014 |
| CR3 Properties Ltd | Real estate | 2021 |
| Crafted Ideas Ltd | Construction | 2025 |
| Cream and Dream Limited | Extraterritorial | 2008 |
| Createdeffect Limited | Real estate | 2018 |
| Createdfx Limited | Arts & recreation | 2020 |
| Creationship Limited | Professional & scientific | 2012 |
| Creative Spaces Croydon Ltd | Construction | 2018 |
| Creative X Ltd | Wholesale & retail | 2004 |
| Crispy Clux Ltd | Hospitality | 2024 |
| Crnp LLP | | 2012 |
| Croham Consulting Ltd | Professional & scientific | 2024 |
| Croham Hurst Golf Club Limited | Arts & recreation | 1961 |
| Croham Hurst Golf Trading Company Limited | Arts & recreation | 2015 |
| Croham Hurst Residents Management Co. Limited | Real estate | 1970 |
| Croham Manor Management Limited | Real estate | 1995 |
| Croham Property Advisory Ltd | Professional & scientific | 2026 |
| Croham Road Operating Company Limited | Arts & recreation | 2024 |
| Cronx Jewellery Limited | Wholesale & retail | 2019 |
| Crossfoot Limited | Wholesale & retail | 2016 |
| Crossfoot Properties Limited | Real estate | 2023 |
| Crowhurst Residents Freeholders Limited | Real estate | 1996 |
| Crown Creative Ideas Limited | Manufacturing | 2025 |
| CROWN46 Company Ltd | Health & social care | 2019 |
| Crownpoint (SE19) Limited | Construction | 2020 |
| Croydivision Ltd | Wholesale & retail | 2021 |
| Croydon & Purley Tyers Ltd | Manufacturing | 2024 |
| Croydon Basketball Club Ltd | Arts & recreation | 2023 |
| Croydon Burgers Ltd | Hospitality | 2023 |
| Croydon Creative Hub Ltd | Wholesale & retail | 2025 |
| Croydon Hearing Resource Centre | Health & social care | 2000 |
| Croydon Heart CIC | Hospitality | 2025 |
| Croydon Jubilee Church | Other services | 2012 |
| Croydon Mens Barbers Ltd | Other services | 2025 |
| Croydon Park Box CIC | Arts & recreation | 2024 |
| Croydon Party Limited | Professional & scientific | 2023 |
| Croydon Pickleball Ltd | Arts & recreation | 2024 |
| Croydon Property Developments Limited | Construction | 2018 |
| Croydon Sports Injury Clinic Limited | Health & social care | 2011 |
| Croydon Vineyard | Other services | 2013 |
| Croydoncryo Ltd | Other services | 2021 |
| Croyweb Ltd | Information & communication | 2001 |
| CRS Electrical Limited | Construction | 2020 |
| Crystal Moss Ltd | Wholesale & retail | 2024 |
| Crystal Palace Pizza & Grill Ltd | Hospitality | 2022 |
| Crystal Turkiz Ltd | Hospitality | 2025 |
| CS Blinds & Shutters Ltd | Wholesale & retail | 2021 |
| Csarchitects Ltd | Professional & scientific | 2019 |