| Cambrian Training Company/Cwmni Hyfforddiant Cambrian Cyfyngedig | Education | 1995 |
| Cambrian Training Holdings Limited | Financial services | 2024 |
| Camlas Farm Vets LLP | | 2013 |
| Camlin Events Ltd | Other services | 2024 |
| Cann Management Services Ltd | Hospitality | 2025 |
| Canter Carpet Limited | Extraterritorial | 2020 |
| Carbon Hill Limited | Other services | 2021 |
| Carpenter & Paterson (Holdings) Limited | Professional & scientific | 1992 |
| Carpenter & Paterson Limited | Manufacturing | 1956 |
| Castalum Limited | Manufacturing | 2008 |
| Celtic Bear Property Ltd | Real estate | 2019 |
| Celtic Company (Mid-Wales) Limited | Wholesale & retail | 1995 |
| Ceri Ryder Creative Ltd | Hospitality | 2021 |
| Cestrian Holdings Ltd | Real estate | 2018 |
| Charlies AG and Turf Limited | Manufacturing | 2023 |
| Charlies Stores Group Limited | Financial services | 2025 |
| Charlies Stores Holdings Limited | Financial services | 2023 |
| Charlies Stores Limited | Wholesale & retail | 1983 |
| Chemostrat Ltd. | Professional & scientific | 1999 |
| Chemostrat Mena Ltd | Professional & scientific | 2011 |
| Cheshire & North Wales Law Society Limited | Other services | 1881 |
| Chris Shuker Building Contractor Limited | Construction | 2007 |
| Chris's Hairlines Ltd | Administrative & support | 2019 |
| Christ Church Welshpool | Arts & recreation | 2013 |
| Chrysalis Studio Ltd | Professional & scientific | 2020 |
| Citadel Joinery Limited | Manufacturing | 2024 |
| Claren Homes Limited | Construction | 1996 |
| Classical Interludes Ltd | Extraterritorial | 2023 |
| Clive Building Company Ltd | Real estate | 1996 |
| Clive Motor Cycle Club Limited | Arts & recreation | 1994 |
| Clives Electrical Limited | Other services | 2012 |
| Clos Brynyddol (Welshpool) Management Company Limited | Households | 2017 |
| Clypeus Ltd | Administrative & support | 2019 |
| Codex Motorsports Ltd | Wholesale & retail | 2020 |
| Coed Y Robin Barn Ltd | Real estate | 2025 |
| Coed-Y-Dinas Farming Limited | Financial services | 2025 |
| Complete Commercial Components Ltd | Other services | 2008 |
| Concrete Solutions Ltd | Extraterritorial | 2024 |
| Cookson Travel Limited | Transport & logistics | 2012 |
| Cooper Holland Leisure Limited | Hospitality | 2021 |
| Cooper Holland Limited | Construction | 2009 |
| Corzak Limited | Administrative & support | 2008 |
| Coscor Limited | Other services | 2021 |
| Cosmic Collectables Ltd | Wholesale & retail | 2020 |
| Country Park Homes Ltd | Construction | 2022 |
| Country Property Innovations Limited | Construction | 2020 |
| Craig a Williams Haulage Ltd | Transport & logistics | 2019 |
| Craven Electrical Wholesalers Limited | Wholesale & retail | 2001 |
| Criddle Overland Ltd | Wholesale & retail | 2026 |
| Cris Knill Projects Ltd | Professional & scientific | 2023 |
| CT Electrical Services (UK) Limited | Construction | 2013 |
| Culinary Association of Wales Limited | Other services | 2004 |
| Curve Vehicle Design Ltd | Information & communication | 2005 |
| Cymric Mill Properties Limited | Real estate | 2001 |
| D a Autos Limited | Wholesale & retail | 2022 |
| D G Forestry Limited | Manufacturing | 2016 |
| D G Tyres Ltd | Wholesale & retail | 2020 |
| D Jones Carpentry & Building Ltd | Construction | 2019 |
| D R Investment Group Limited | Wholesale & retail | 2018 |
| D R Morris Farms Limited | Agriculture & fishing | 2012 |
| D&S Rentals Ltd | Real estate | 2024 |
| D.Wolverson Ltd | Wholesale & retail | 2024 |
| Daisy Bank Lodges Limited | Extraterritorial | 2014 |
| Daniel John Davies Limited | Extraterritorial | 2022 |
| Darren Williams Carpets, Flooring & Beds Ltd | Wholesale & retail | 2025 |
| Dastpech Ltd | Construction | 2019 |
| Datblygiadau KKD Developments Limited | Construction | 2019 |
| Dave Gore Tyres Limited | Real estate | 2015 |
| David Bryson Consulting and Coaching Ltd | Professional & scientific | 2023 |
| Dawson Shanahan (Wales) Limited | Manufacturing | 2009 |
| Dawson Shanahan Limited | Manufacturing | 1943 |
| DD Builders Powys Ltd | Construction | 2023 |
| Deastra Ltd. | Professional & scientific | 2012 |
| Depo Properties Ltd | Real estate | 2023 |
| Depo Self Storage Ltd | Transport & logistics | 2026 |
| Depobox Limited | Financial services | 2025 |
| Derwen Farm Shop Ltd | Wholesale & retail | 2021 |
| Derwen Garden Centre Limited | Wholesale & retail | 2013 |
| Derwen Mill Holiday Park Limited | Hospitality | 2003 |
| Designsingle Limited | Professional & scientific | 1996 |
| DGO Accounting Solutions Ltd | Professional & scientific | 2003 |
| DH Spice UK Ltd | Hospitality | 2023 |
| Dingle Nurseries Holdings Limited | Financial services | 2024 |
| Dingle Nurseries Limited | Wholesale & retail | 2004 |
| DM Roberts Contractors Limited | Agriculture & fishing | 2022 |
| Dol-Y-Neuadd Ltd | Hospitality | 2020 |
| Dolgead Hall Caravan Park Limited | Hospitality | 2001 |
| Dolgead Hall Holdings Limited | Financial services | 2018 |
| Dolwen Farms Ltd | Agriculture & fishing | 2008 |
| Door Closer Direct Ltd | Professional & scientific | 2005 |
| DPH Leisure Ltd | Hospitality | 2023 |
| Dragon Deployables Limited | Manufacturing | 2024 |
| Dragon Liquid Screed Limited | Construction | 2017 |
| Dragon Rendering Ltd | Construction | 2020 |
| DRJ Builders (Wales) Limited | Construction | 2003 |
| DSE Property Limited | Real estate | 2023 |
| DTS Construct Ltd | Construction | 2021 |
| Dyfodol Ltd | Health & social care | 2023 |
| Dynacast (AH1) Limited | Professional & scientific | 2002 |
| Dynacast (UK) Limited | Manufacturing | 2000 |