| Tregaron WAR Memorial Hall Limited | Extraterritorial | 2006 |
| Truck & Plant Drive Ltd | Administrative & support | 2025 |
| Tryal Property Investments Ltd | Construction | 2024 |
| Ty-Fi CYF | Education | 2026 |
| Tynrhos Camping and Fishing Ltd | Agriculture & fishing | 2022 |
| Ubuntu Services Ltd | Health & social care | 2016 |
| Vintage Catering Limited | Hospitality | 2010 |
| W. D. Jones | | 1988 |
| Ward Cleaning Limited | Administrative & support | 2025 |
| Waters and Neale Ltd | Agriculture & fishing | 2016 |
| Waun Castle Farm Ltd | Agriculture & fishing | 2023 |
| Webdapper Ltd | Information & communication | 2014 |
| WES Glei Cyfyngedig | Information & communication | 1995 |
| West Coast Autos Ltd | Wholesale & retail | 2025 |
| West Wales Chimney Sweeping Limited | Administrative & support | 2024 |
| West Wales Laser Technologies Ltd | Administrative & support | 2025 |
| West Wales Lettings Ltd | Real estate | 2014 |
| West Wales Rural Enterprises Ltd | Agriculture & fishing | 2022 |
| West Wales Stoves Ltd | Administrative & support | 2018 |
| WET Nose Publishing Ltd | Information & communication | 2012 |
| Whiteland Restorations Ltd | Wholesale & retail | 2023 |
| Wildernest Care Farm CIC | Education | 2021 |
| Williams & Thomas Limited | Construction | 2012 |
| Willsbo CYF | Professional & scientific | 2008 |
| WJH Trans N Haul Limited | Transport & logistics | 2020 |
| WMS Firearms Training Ltd | Arts & recreation | 2011 |
| WMS Rifle Academy Ltd | Arts & recreation | 2013 |
| Wpcs Trading Ltd. | Extraterritorial | 1994 |
| WYN Thomas Heating Limited | Construction | 2005 |
| Y Co FI Ltd | Hospitality | 2025 |
| Y Stiwdio Brint LLP | | 2016 |
| Yambi Limited | Professional & scientific | 2017 |