| Castle Market 24 Ltd | Wholesale & retail | 2026 |
| Castle View (Deganwy) Limited | Hospitality | 2017 |
| Cefn Cottages Ltd | Hospitality | 2024 |
| Celtic Shops (Trefriw) Limited | Wholesale & retail | 1978 |
| Celtic Wellbeing Ltd | Manufacturing | 2011 |
| Characters Tea House & Restaurant Ltd | Hospitality | 2011 |
| Chemsol Cymru Limited | Other services | 2002 |
| Cherrys Vehicle Leasing LLP | | 2012 |
| Chwilog (CAE Bodlondeb) Management Company Ltd | Households | 2023 |
| Cleaner Care Limited | Administrative & support | 2005 |
| Clifftops (Colwyn Bay) Management Company Limited | Real estate | 2007 |
| Clipper Developments Limited | Construction | 2006 |
| Clwb Enfys Ltd | Health & social care | 2005 |
| Clwyd Refrigeration Limited | Extraterritorial | 2016 |
| Coaching in Partnership Limited | Education | 2001 |
| Coastal Inns Limited | Hospitality | 2010 |
| Colin Price IT Solutions Ltd | Information & communication | 2000 |
| Colwyn Bay Motor Cycles Limited | Wholesale & retail | 1988 |
| Construct GI Limited | Construction | 2016 |
| Contrado Digital Ltd | Information & communication | 2013 |
| Conway Court (Llandudno) Limited | Real estate | 1989 |
| Conwy (Caernarvonshire) Golf Club Limited | Hospitality | 2014 |
| Conwy Boat Trips Ltd | Administrative & support | 2023 |
| Conwy Borough Football Club C.I.C. | Arts & recreation | 2012 |
| Conwy Cottages Ltd | Hospitality | 2019 |
| Conwy Creative Ltd | Arts & recreation | 2021 |
| Conwy Distillery Limited | Manufacturing | 2018 |
| Conwy Driveways Ltd | Administrative & support | 2023 |
| Conwy Fencing Limited | Wholesale & retail | 2003 |
| Conwy Holiday Park Limited | Hospitality | 2015 |
| Conwy Homes Limited | Construction | 2002 |
| Conwy Kombucha Limited | Manufacturing | 2018 |
| Conwy Lodge Park Limited | Hospitality | 2019 |
| Conwy Physio Clinic Limited | Health & social care | 2015 |
| Conwy Valley Systems Limited | Information & communication | 1997 |
| Courtia Joinery Ltd | Construction | 2013 |
| CP Garden Design Ltd | Administrative & support | 2015 |
| Craig-Y-Don Printing Works Limited(The) | Manufacturing | 1964 |
| Cranford Court Rhos-On-Sea Management Company Limited | Households | 1973 |
| Crave Food Limited | Hospitality | 2025 |
| Creamer Company Limited | Administrative & support | 2018 |
| Crensiog Holdings Limited | Real estate | 2018 |
| CRJ Facilities Maintenance Ltd | Construction | 2020 |
| CRL Group Ltd | Energy | 1980 |
| Cucurucu Limited | Wholesale & retail | 2024 |
| Cwmni Gwynt TEG CYF | Administrative & support | 1998 |
| Cwrt Capel (Rhos on Sea) Management Company Limited | Households | 2008 |
| Cwrt Deganwy Freehold Limited | Households | 2012 |
| Cybernesia Ltd. | Professional & scientific | 1999 |
| D & B Management Services Limited | Wholesale & retail | 2002 |
| D & J Leisure Holdings Limited | Professional & scientific | 2005 |
| D J H Communications Ltd | Wholesale & retail | 2009 |
| D L Hughes Limited | Water & waste | 2001 |
| D. E. Parry (Joinery) Limited | Construction | 2002 |
| D. Parisella & Sons Limited | Manufacturing | 1973 |
| D.M.(N.W.) Ltd | Manufacturing | 2013 |
| Dance Collective CIC | Arts & recreation | 2013 |
| Darklight Entertainment Limited | Arts & recreation | 2019 |
| Darnic Holdings Ltd | Real estate | 2026 |
| Dash N Dine Takeaway Services Limited | Hospitality | 2025 |
| DB Operator Services UK Limited | Construction | 2016 |
| Deganwy Castle Management Company Limited | Real estate | 2012 |
| Deganwy Dental Practice Ltd | Health & social care | 2009 |
| Deganwy OUT of School Club Limited | Other services | 2003 |
| Delivered Design Limited | Professional & scientific | 2012 |
| Desiderata Residential Limited | Real estate | 2021 |
| Designed to Save Limited | Administrative & support | 2010 |
| DPB TM Ltd | Construction | 2018 |
| DPW3 Ltd | Professional & scientific | 2019 |
| Dragon Cleaning Services Ltd | Administrative & support | 2023 |
| Dragon Enforcement Ltd | Financial services | 2016 |
| Draig Property Ltd | Real estate | 2026 |
| Dulyn Construction Ltd | Construction | 2025 |
| Duncan Spencer Limited | Agriculture & fishing | 2024 |
| Easy Clean Car Centre Limited | Wholesale & retail | 2006 |
| Ecoscope Highways Limited | Professional & scientific | 2016 |
| Ecoscope Limited | Professional & scientific | 2014 |
| EFL Steel Solutions Limited | Construction | 2023 |
| Eiddo 2020 Properties Limited | Real estate | 2020 |
| Eldridian Cleaning Services Ltd | Administrative & support | 2020 |
| Elite Golf Rooms Limited | Arts & recreation | 2025 |
| Ellis Automotive Limited | Wholesale & retail | 2026 |
| Emily Owen Consultancy Ltd | Professional & scientific | 2025 |
| Emotionmedia Ltd | Information & communication | 2013 |
| Engaging Diversity Limited | Professional & scientific | 1999 |
| Engineering Systems Training Ltd | Professional & scientific | 2010 |
| Escape Hotels Limited | Hospitality | 2003 |
| Escape Spa & Beauty Ltd | Other services | 2022 |
| Esthetig Ltd | Information & communication | 2007 |
| EWE Felty Thing Ltd | Wholesale & retail | 2018 |
| Express Marble and Granite Ltd | Wholesale & retail | 2016 |
| F M Murphy Limited | Real estate | 2025 |
| Fairy Glen (Capelulo) Limited | Hospitality | 2003 |
| Fern Villa Management Company Limited | Households | 2010 |
| Fielhaus Limited | Real estate | 2002 |
| Find Your Inner Spark Ltd | Health & social care | 2020 |
| Fingerprints Art Limited | Wholesale & retail | 2003 |
| Flintshire Joinery & Building Ltd | Manufacturing | 2025 |
| Flush Heating Ltd | Construction | 2022 |
| FLY Direct From Limited | Professional & scientific | 2005 |