| Census Systems Ltd | Professional & scientific | 2014 |
| CEW Properties Ltd | Real estate | 2018 |
| Chainbridge Hotel Ltd | Hospitality | 2026 |
| Cherry Tree AIM Ltd | Professional & scientific | 2020 |
| Cherry Tree Consulting Limited | Other services | 2018 |
| Chevron Interserve Limited | Real estate | 2012 |
| Chic Woman Ltd | Arts & recreation | 2011 |
| Chris Allen Group Ltd | Financial services | 2020 |
| Chris Allen Plumbing & Heating Limited | Construction | 2013 |
| Chris Allen Renewable Solutions Ltd | Construction | 2021 |
| Church Manor Care Home Ltd | Health & social care | 2012 |
| Chwaraeon M D Sports CYF | Health & social care | 2014 |
| Cinq-Zéro-Cinq Ltd | Wholesale & retail | 2018 |
| CKR Sales Ltd | Other services | 2019 |
| CKW Wind Ltd | Professional & scientific | 2024 |
| CLD Assessment Limited | Health & social care | 2017 |
| Clear View Mortgages Ltd | Administrative & support | 2016 |
| Club Boutique Limited | Extraterritorial | 2016 |
| Clutha Consultancy Services Ltd | Professional & scientific | 2024 |
| CLW Renewables Ltd | Construction | 2026 |
| Clwb Rygbi Dinbych (Trading) Limited | Hospitality | 2024 |
| Clwyd Community Broadcasting Limited | Information & communication | 2019 |
| Clwyd Homes Limited | Construction | 2004 |
| Clwyd Recruitment Solutions Ltd | Administrative & support | 2023 |
| Clwydian Cartography Limited | Agriculture & fishing | 2019 |
| CMA Properties Ltd | Real estate | 2018 |
| CMJ Properties (North Wales) Ltd | Real estate | 2020 |
| CNS Developments Ltd | Manufacturing | 2018 |
| Coastal Construction & Renovation Services Limited | Construction | 2018 |
| Coastal Towbar Services Limited | Other services | 1998 |
| Coastal Tree Services Ltd | Agriculture & fishing | 2022 |
| Coed Celyn Limited | Real estate | 2014 |
| Coed-Y-Arian Estate Ltd | Hospitality | 2023 |
| Colbek Systems Limited | Information & communication | 1987 |
| Colecloughs' Farms Limited | Agriculture & fishing | 2012 |
| Colwyn Corn Supplies Ltd | Other services | 2021 |
| Conifer Property Services Ltd | Construction | 2009 |
| Construction Project Safety Ltd | Professional & scientific | 2009 |
| Conwy and Denbighshire Mental Health Advocacy Service (Cadmhas) Ltd | Health & social care | 2008 |
| Conwy Property Company Ltd | Real estate | 2023 |
| Conwy Property Group Limited | Real estate | 2024 |
| Core TEC Solutions Limited | Manufacturing | 2015 |
| Cornerstone Property Services (NW) Ltd | Construction | 2018 |
| Cotswolds Heritage Building Contractors Ltd | Construction | 2017 |
| CP Plumbing & Heating Services Ltd | Construction | 2015 |
| CR Construction (North Wales) Ltd | Construction | 2016 |
| Craiglets Limited | Hospitality | 2025 |
| Craven Asset Management Ltd | Extraterritorial | 2018 |
| Cresthouse Limited | Hospitality | 2007 |
| Creuddyn (Management) Ltd | Professional & scientific | 2006 |
| Crispy COD (NW) Limited | Hospitality | 2015 |
| Crosville Coop Ltd | Real estate | 2019 |
| Crystal Rooms (Bangor) Limited | Real estate | 1988 |
| Ctmljs Limited | Professional & scientific | 2010 |
| Cues Sports Bar Limited | Hospitality | 2014 |
| Customs Curtains & Blinds Limited | Wholesale & retail | 2006 |
| Customs Transformation Limited | Professional & scientific | 2025 |
| Cwrw LON CAE Glas CYF | Hospitality | 2025 |
| D LL & G a Jones CYF | Agriculture & fishing | 2022 |
| D O Roberts Limited | Construction | 2020 |
| D P Forestry Limited | Agriculture & fishing | 2016 |
| D W Jones Limited | Construction | 2024 |
| D.Kett Limited | Real estate | 2004 |
| D.P.L.(Abergele) Ltd | Hospitality | 2014 |
| Daffodil Holdings Limited | Real estate | 2023 |
| Daforce Limited | Information & communication | 2026 |
| David Glover Ltd | Other services | 2019 |
| David John Hunter Services Ltd | Construction | 2023 |
| Davies Connections Limited | Construction | 2021 |
| Davies Transport and Plant Services Ltd | Construction | 2016 |
| Day Rate Stays Ltd | Real estate | 2021 |
| Dayclox Limited | Wholesale & retail | 2013 |
| DBI Control Limited | Manufacturing | 2011 |
| Defender Training and Response Ltd | Public administration | 2025 |
| Deganwy Engineering Ltd | Other services | 2019 |
| Delwydd Developments Ltd | Construction | 2022 |
| Denbighshire Deck Movers Limited | Construction | 2022 |
| Denbighshire Foyer Limited | Health & social care | 1997 |
| Dent Monkey Ltd | Administrative & support | 2016 |
| Designer Nutrition T/A Hammer Nutrition Ltd | Health & social care | 2019 |
| Designweb DMA Limited | Information & communication | 2015 |
| Deva Court Property Limited | Households | 2019 |
| Deva Roman Experience Limited | Construction | 1993 |
| Dflj Ltd | Hospitality | 2022 |
| Diamond Cleaning (What CAN Shine Will Shine) Ltd | Administrative & support | 2012 |
| Divine Thai Limited | Other services | 2016 |
| DJB Group Storage Ltd | Administrative & support | 2022 |
| DJJ E-Consults Limited | Other services | 2014 |
| DMV Estates Limited | Real estate | 2025 |
| Dntr Ltd | Other services | 2018 |
| Dogstar Digital Limited | Professional & scientific | 2021 |
| DOL Eryri Ltd | Hospitality | 2025 |
| Dolhyfryd Court Management Company Limited | Real estate | 2005 |
| Dolwar Residential Home Ltd | Health & social care | 2023 |
| Domus House Management Company Limited | Hospitality | 2014 |
| Donut (H.R.) Limited | Extraterritorial | 2010 |
| Donut International Limited | Professional & scientific | 2002 |
| Donut Safeland Limited | Professional & scientific | 2000 |
| Donut Safety Systems Limited | Financial services | 1988 |
| Door 77 Ltd | Hospitality | 2019 |