| Chilburn Gardens (Management) Company Limited | Real estate | 2014 |
| Chimtec Limited | Construction | 2006 |
| Chiron Trading Ltd | Professional & scientific | 2023 |
| Choice Takeaway Ltd | Hospitality | 2025 |
| Cholan Ltd | Health & social care | 2023 |
| Choova Ltd | Information & communication | 2023 |
| Christy Court (Chelmsford) Management Limited | Households | 1989 |
| Cindy Lou’S Hair and Beauty Ltd | Wholesale & retail | 2024 |
| Cirveris Ltd | Information & communication | 2026 |
| Citizens Advice Bureau Tendring | Public administration | 2001 |
| Citrus Clicks Limited | Professional & scientific | 2024 |
| City XXS Limited | Other services | 2022 |
| Cjavi Trading Ltd | Other services | 2020 |
| CJP Mechanical Services Limited | Construction | 2023 |
| CK Property Improvements Ltd | Construction | 2019 |
| CK2CARE Limited | Health & social care | 2019 |
| Clacton and District Indoor Bowls Club Limited | Arts & recreation | 2005 |
| Clacton Art Craft & Model Centre Ltd | Wholesale & retail | 2024 |
| Clacton Barbershop Ltd | Other services | 2026 |
| Clacton Bathroom Centre Ltd. | Wholesale & retail | 1997 |
| Clacton Body Repairs Ltd | Wholesale & retail | 2023 |
| Clacton Business Services Limited | Professional & scientific | 2008 |
| Clacton Car UK Limited | Wholesale & retail | 2017 |
| Clacton Car Wash Limited | Wholesale & retail | 2024 |
| Clacton Coastal Mental Wellbeing C.I.C. | Health & social care | 2023 |
| Clacton Coastal Windows Limited | Construction | 2023 |
| Clacton Convenience Store Ltd | Wholesale & retail | 2025 |
| Clacton DIO Ltd | Wholesale & retail | 2025 |
| Clacton Eats Group Limited | Information & communication | 2022 |
| Clacton Essex Store's Ltd | Wholesale & retail | 2023 |
| Clacton Funeral Service Ltd | Other services | 2003 |
| Clacton Grill Ltd | Hospitality | 2025 |
| Clacton Hydro Ltd | Wholesale & retail | 2025 |
| Clacton Kayak Rental Ltd | Arts & recreation | 2020 |
| Clacton Landscapes Ltd | Construction | 2017 |
| Clacton Metal Recycling Ltd | Water & waste | 2013 |
| Clacton Motorist Discount Limited | Manufacturing | 2003 |
| Clacton Pride CIC | Other services | 2020 |
| Clacton PUB Company Ltd | Hospitality | 2025 |
| Clacton Renewables Ltd | Construction | 2022 |
| Clacton Rentals Limited | Real estate | 2022 |
| Clacton Specsavers Limited | Wholesale & retail | 1995 |
| Clacton Sports Bar Limited | Hospitality | 2026 |
| Clacton Tile Centre Limited | Construction | 1974 |
| Clacton Town Hand Car Wash Ltd | Other services | 2020 |
| Clacton Tyre & Service Centre Ltd | Wholesale & retail | 2022 |
| Clacton Valeting Ltd | Administrative & support | 2022 |
| Clacton-On-Sea Bowling Club Limited | Arts & recreation | 2019 |
| Clad-Glaze Ltd | Construction | 2016 |
| Clarke & Sons Roofing Ltd | Construction | 2018 |
| Clarke Energy Group Ltd | Construction | 2026 |
| Classic Boutique 24/7 Ltd | Wholesale & retail | 2026 |
| Classic Wings (Flying) Limited | Transport & logistics | 1995 |
| Clay Hall Crescent Management Company Limited | Real estate | 2019 |
| Claydon-Voss Retail Ltd | Wholesale & retail | 2019 |
| Clean Drainage Facilities Ltd | Administrative & support | 2022 |
| Clean Spot Co Clacton Ltd | Administrative & support | 2025 |
| Cleanbit Limited | Administrative & support | 2024 |
| Clear Cashflow Consulting Ltd | Professional & scientific | 2026 |
| Clear Print Cards Ltd | Wholesale & retail | 2024 |
| Clerissa Ltd | Administrative & support | 2024 |
| Clever OR Never Ltd | Information & communication | 2024 |
| Clive Boyce Ltd | Construction | 2026 |
| CLX Windows Ltd | Administrative & support | 2026 |
| CMG Consulting Ltd | Construction | 2021 |
| Co Clean Ltd | Administrative & support | 2023 |
| Coast Design & Build Ltd | Construction | 2022 |
| Coastal Car & Leisure Ltd | Wholesale & retail | 2010 |
| Coastal Car Sales Ltd | Wholesale & retail | 2023 |
| Coastal Enterprises Limited | Wholesale & retail | 2003 |
| Coastal Groomers Limited | Other services | 2021 |
| Coboticcare Ltd | Information & communication | 2021 |
| Codgers of Clacton Ltd | Wholesale & retail | 2012 |
| Coffey Brooks Financial Services Ltd | Financial services | 2002 |
| Coffey Tomkins Financial Services Ltd | Financial services | 2015 |
| Colchester Chinese Culture Society CIC | Arts & recreation | 2021 |
| Colchester Investments Limited | Professional & scientific | 2020 |
| Colchester Militaria Ltd | Wholesale & retail | 2020 |
| Colchester Turf Supplier Ltd | Administrative & support | 2026 |
| Colibri Flyght Ltd | Construction | 2020 |
| Colne Valley Riding Club Ltd | Other services | 2023 |
| Color Fashion Crafts Ltd | Arts & recreation | 2025 |
| Connaught Road Management Co. Limited | Households | 2019 |
| Connoisseur Vintners Ltd | Professional & scientific | 2026 |
| Constav Construction Limited | Construction | 2025 |
| Construction MS Services Limited | Professional & scientific | 2017 |
| Coopers Electrical Ltd | Construction | 2022 |
| Coral Solutions Ltd | Administrative & support | 2018 |
| Cosy Host Ltd | Information & communication | 2025 |
| Counselling in Education Ltd | Other services | 2017 |
| Country Trade Limited | Real estate | 2000 |
| Cousins Heating & Renewables LLP | | 2011 |
| Crane Ventures Ltd | Administrative & support | 2012 |
| CRC Project Management Ltd | Professional & scientific | 2015 |
| Credon Plants Ltd | Wholesale & retail | 2026 |
| Crest Improvements Limited | Construction | 1985 |
| Crew Catering Limited | Wholesale & retail | 2003 |
| Crisp Property Solutions Ltd | Real estate | 2025 |
| Crispins Catering Ltd | Hospitality | 2017 |
| Crofty’S Sandwich Shop Ltd | Hospitality | 2023 |