| Catalin 2018 Ltd | Transport & logistics | 2018 |
| Catchwater Ltd | Energy | 2013 |
| Caytoft Farms Limited | Agriculture & fishing | 1952 |
| CBM & Sons Limited | Construction | 2017 |
| CC81 Limited | Financial services | 2017 |
| CCE Transport Limited | Administrative & support | 2017 |
| CDM Accountants Limited | Professional & scientific | 2018 |
| Cecconi Healthcare Limited | Professional & scientific | 2019 |
| Cedar Medical Services Limited | Health & social care | 2025 |
| Celestra Consulting Ltd | Wholesale & retail | 2013 |
| Center for Public Interest Research, Inc. | | 2025 |
| Centre for International Medical Graduates Ltd | Education | 2023 |
| Centrepoint Outreach | Health & social care | 1996 |
| Chablani Consultancy Services Ltd | Health & social care | 2023 |
| Chambers & SON Building Maintenance Limited | Construction | 2017 |
| Chambers Building Maintenance Limited | Construction | 2010 |
| Chang Phueak Gym (Boston) Ltd | Arts & recreation | 2024 |
| Chanson Flowers & Plants Limited | Wholesale & retail | 2004 |
| Charcoal Grill Pizza House Ltd | Hospitality | 2025 |
| Charles Wright & Sons Limited | Transport & logistics | 1952 |
| Charlotte Chalmers Clinic Ltd | Other services | 2024 |
| Chas Wright Farms Ltd | Agriculture & fishing | 2022 |
| Chaserossproperties Ltd | Real estate | 2026 |
| Chateau Felicien Ltd | Wholesale & retail | 2022 |
| Chaurasia Medical Services Limited | Health & social care | 2009 |
| Cheer's Nurseries Limited | Agriculture & fishing | 2005 |
| Chenery Fitness Ltd | Other services | 2025 |
| Cheryldean Limited | Wholesale & retail | 2006 |
| Chester's Carpets & Flooring Ltd | Wholesale & retail | 2016 |
| Chicken Palace Boston’S Limited | Hospitality | 2024 |
| Chimpreach Ltd | Professional & scientific | 2023 |
| Chmolek Ltd | Transport & logistics | 2018 |
| Choice Real Estate Ltd | Real estate | 2023 |
| Choicestream, Inc. | | 2015 |
| Chompp Ltd | Hospitality | 2024 |
| Chris Fountain Limited | Manufacturing | 2003 |
| Chris Mcgowan Limited | Construction | 2012 |
| Chris Sellars Groundcare Ltd | Manufacturing | 2015 |
| Christel Music Limited | Information & communication | 1983 |
| Chroniq Biomedical Ltd | Wholesale & retail | 2026 |
| CHS Management Limited | Professional & scientific | 2009 |
| Chuksfeller Limited | Health & social care | 2025 |
| Church Road Trading Limited | Wholesale & retail | 2018 |
| Cirrus IT Solutions Limited | Wholesale & retail | 2023 |
| Citadelroute Immigration Ltd | Professional & scientific | 2026 |
| Citisoft, Inc. | | 2021 |
| Citizens Advice Lincolnshire | Information & communication | 2012 |
| Citizens Advice MID Lincolnshire | Other services | 2005 |
| CJ Health Limited | Health & social care | 2019 |
| CK Lincs Ltd | Real estate | 2025 |
| CL LET Ltd | Real estate | 2025 |
| Clad Plus Facades Ltd | Construction | 2016 |
| Claire Mason Manipulative Therapist Limited | Health & social care | 2006 |
| Claristar Ltd | Arts & recreation | 2021 |
| Clarke Group Construction Limited | Construction | 1999 |
| Clarke Property Group Ltd | Real estate | 2023 |
| Clarkes Cleaning Services Ltd | Administrative & support | 2015 |
| Clarks Car Cleaning Ltd | Wholesale & retail | 2025 |
| Class Images Ltd | Professional & scientific | 2011 |
| Classic Homes (Lincs) Limited | Construction | 2002 |
| Clayton-Lenton (Transport) Limited | Transport & logistics | 2003 |
| Clean 143 Limited | Administrative & support | 2017 |
| Cleancut (Kirton Holme) Limited | Extraterritorial | 2006 |
| Clhlettings Ltd | Hospitality | 2023 |
| Clickamobile Limited | Wholesale & retail | 2016 |
| Clive Edwards Ltd | Wholesale & retail | 2024 |
| CLJ Window Cleaning Services Ltd | Administrative & support | 2021 |
| Clockwork Studios Prescot CIC | Administrative & support | 2022 |
| Clothes Exchange Limited | Wholesale & retail | 2025 |
| CM Textiles Ltd | Wholesale & retail | 2025 |
| Cmaduka Limited | Real estate | 2025 |
| Cmits Limited | Information & communication | 2014 |
| CMN Insight Ltd | Professional & scientific | 2026 |
| CMS Management (Boston) Limited | Professional & scientific | 2016 |
| Coach House Design | | 1990 |
| Coastal Caravans Ltd | Wholesale & retail | 2024 |
| Cobra Vending Limited | Wholesale & retail | 2021 |
| Code & Growth Ltd | Information & communication | 2026 |
| Code Integrations Ltd | Wholesale & retail | 2022 |
| Cognitive Canine Company Ltd | Wholesale & retail | 2023 |
| Cola Training Services Limited | Education | 2004 |
| Colby Motorcycles Ltd | Wholesale & retail | 2018 |
| Colin Huggins Windscreens Ltd | Wholesale & retail | 2015 |
| Colin Stott Consultancy Services Ltd | Professional & scientific | 2019 |
| Collaboration Careers Ltd | Administrative & support | 2025 |
| Comelu HGV Trans Ltd | Transport & logistics | 2024 |
| Commercial and Industrial Roofing Ltd | Construction | 2026 |
| Community Hubland Ltd | Information & communication | 2021 |
| Community Maintenance Service CIC | Extraterritorial | 2022 |
| Company Startup Limited | Administrative & support | 2010 |
| Concept Smoke Screen Limited | Administrative & support | 1992 |
| Coney's (Tailors) Limited | Real estate | 1958 |
| Coney's of Lincoln Limited | Wholesale & retail | 2012 |
| Confident Homes Limited | Real estate | 2021 |
| Coningsby Pet and Aquatics Ltd | Wholesale & retail | 2020 |
| Consus Fresh Solutions Ltd | Information & communication | 2016 |
| Contain Yourself Ltd | Transport & logistics | 2023 |
| Conte International Limited | Wholesale & retail | 2015 |
| Contractor Connect Group Ltd | Administrative & support | 2025 |
| Convosco Conversions Ltd | Wholesale & retail | 2024 |