| Coalbrook Motors Ltd | Wholesale & retail | 2004 |
| Coast Carpentry and Building Ltd | Construction | 2025 |
| Coast Carpentry and Renovations Limited | Construction | 2021 |
| Coast Financial Solutions Ltd | Financial services | 2023 |
| Coast Property and Rental Limited | Real estate | 2023 |
| Coastal Cleaning Group Ltd | Administrative & support | 2024 |
| Coastal Construction Services Limited | Construction | 2016 |
| Coastal Fitness Ltd | Arts & recreation | 2019 |
| Coastal Luxury Escapes Ltd | Hospitality | 2025 |
| Coastal Roofing & Building Limited | Construction | 2020 |
| Coastal Scaffolding Ltd | Construction | 2015 |
| Coastep Properties Limited | Real estate | 2022 |
| Coastline Coffee Roasters Limited | Manufacturing | 2025 |
| Coastline Heating Services Limited | Construction | 2019 |
| Coastshore Limited | Health & social care | 2014 |
| Coates Developments Limited | Construction | 2023 |
| Coatings and Blasting Services Limited | Construction | 2012 |
| Coatlab Customs Ltd | Wholesale & retail | 2026 |
| Cobalt Property Limited | Financial services | 2023 |
| Cobs & Co Ltd | Hospitality | 2011 |
| Cochrane Opportunity Enterprises Limited | Real estate | 2002 |
| Coco Baby & Co Ltd | Wholesale & retail | 2021 |
| Coco's Pembrokeshire Ltd | Hospitality | 2020 |
| Cocos Mexican Cuisine Ltd | Hospitality | 2024 |
| Coda Developers Limited | Real estate | 2005 |
| Coda SA1 LLP | | 2006 |
| Codash Management Limited | Real estate | 2017 |
| Code Canvas Limited | Information & communication | 2022 |
| Code Sports & Media Limited | Arts & recreation | 2024 |
| Coding Cottage Limited | Information & communication | 2018 |
| Coed Bach Park Community Bowls Association Limited | Arts & recreation | 2017 |
| Coed Derw Ltd | Health & social care | 2018 |
| Coed Dewi Sant Ltd | Extraterritorial | 2012 |
| Coedargraig Estate Limited | Real estate | 1956 |
| Coeden Fach Community Interest Company | Agriculture & fishing | 2013 |
| Coedffaldau Holdings Limited | Real estate | 2025 |
| Coexistiir Offshore Limited | Professional & scientific | 2022 |
| Coffee Blue (Swansea East) Limited | Hospitality | 2020 |
| Coffee Koub Limited | Manufacturing | 2025 |
| Coffee Post Limited | Hospitality | 2016 |
| Coffee Refinery Limited | Hospitality | 2024 |
| Coffeechy Limited | Manufacturing | 2025 |
| Coffi @ the Foundry Limited | Hospitality | 2026 |
| Cofi Tech Limited | Health & social care | 2013 |
| COI Property Group Limited | Real estate | 2019 |
| Coigolf Limited | Real estate | 2019 |
| Coity Developments SPV 1 Ltd | Construction | 2023 |
| Colasanto Academy of Dance Limited | Arts & recreation | 2023 |
| Cole Builders (Swansea) Limited | Extraterritorial | 2010 |
| Coleridge Homes Limited | Health & social care | 2003 |
| Coles (Mumbles) Ltd | Real estate | 2022 |
| Colesamuel Limited | Administrative & support | 2021 |
| Colgas Ltd | Construction | 2025 |
| Colin Bowen Water Services Ltd | Construction | 2012 |
| College Farm Coity Ltd | Agriculture & fishing | 2025 |
| College of Islamic Studies Ltd | Information & communication | 2026 |
| Colliers ROW Ltd | Administrative & support | 2018 |
| Colomb Holdings Limited | Financial services | 2020 |
| Colomb Investments Limited | Real estate | 2020 |
| Colony Group Limited | Real estate | 2020 |
| Colony Investment Property Limited | Real estate | 2020 |
| Colony Living Management Limited | Real estate | 2020 |
| Color Harmony Ltd | Construction | 2026 |
| Colour Match Services Ltd | Manufacturing | 2021 |
| Colt Garden & Waste Ltd | Water & waste | 2024 |
| Colt Renovation Ltd | Construction | 2018 |
| Colwyn Fish Bar Limited | Hospitality | 2021 |
| Combined Management Support Limited | Professional & scientific | 2016 |
| Combustible Lemons Limited | Health & social care | 2024 |
| Comex IT Limited | Information & communication | 2007 |
| Comfortable Stay Ltd | Real estate | 2024 |
| Commercial Cleaning Contracts Ltd | Administrative & support | 2021 |
| Commercial Cleaning Solutions Limited | Administrative & support | 2026 |
| Commercial Door Parts Ltd | Wholesale & retail | 2024 |
| Commercial Inn Brynhyfryd Ltd | Hospitality | 2025 |
| Commercial Plasmarl Limited | Hospitality | 2024 |
| Commercial Property Advice Limited | Professional & scientific | 2014 |
| Common Meeple Limited | Hospitality | 2022 |
| Community Advantage CIC | Education | 2020 |
| Community Companions R US Limited | Administrative & support | 2026 |
| Community Creators Ltd | Extraterritorial | 2023 |
| Community Junction Limited | Other services | 2014 |
| Community Lives Consortium | Health & social care | 2015 |
| Community MAG (Swansea) Limited | Administrative & support | 2019 |
| Community Scope Ltd | Information & communication | 2025 |
| Compact Club Limited | Wholesale & retail | 2025 |
| Company Formations UN Limited | Extraterritorial | 2013 |
| Company Portals Ltd | Administrative & support | 2016 |
| Company ZMT Limited | Construction | 2019 |
| Compare Insurance Ltd. | Financial services | 2009 |
| Compare Life Insurance Ltd | Financial services | 2007 |
| Compare Properties Ltd | Administrative & support | 2009 |
| Compass Bookkeeping & Accountancy Ltd | Professional & scientific | 2012 |
| Compass Insurance Management Limited | Professional & scientific | 2002 |
| Compass International Trading Limited | Manufacturing | 1992 |
| Complete CAD & Structural (CCS) Solutions Limited | Professional & scientific | 2018 |
| Complete Flooring Solutions Wales Limited | Construction | 2010 |
| Complete Leasing Limited | Administrative & support | 2016 |
| Compliance Safety Services Limited | Construction | 2025 |
| Components UN Limited | Extraterritorial | 2013 |