| WAR Paws | Other services | 2013 |
| Wardill Motorcycle Company Ltd. | Manufacturing | 2017 |
| Warmco UK Ltd | Wholesale & retail | 2025 |
| Watson Tarr Consulting Limited | Professional & scientific | 2021 |
| Watts Building and Property Services Limited | Construction | 2010 |
| Waykar Ltd | Wholesale & retail | 2026 |
| Waymaker Store Ltd | Wholesale & retail | 2023 |
| Wayne Langley Maintenance Engineering Limited | Manufacturing | 2014 |
| Wayne Samways Jiujitsu Ltd | Health & social care | 2025 |
| WC HO Limited | Hospitality | 2017 |
| WD Roofing & Cladding Limited | Construction | 2019 |
| Wdieeff Ltd | Wholesale & retail | 2025 |
| Wear Go WIG Inc Ltd | Wholesale & retail | 2025 |
| Wearthink Innovations (UK) Limited | Wholesale & retail | 2024 |
| Web Esales Limited | Wholesale & retail | 2025 |
| Webbinart Ltd | Information & communication | 2016 |
| WEBLINK4U Limited | Information & communication | 2000 |
| WEI HUA Limited | Hospitality | 2009 |
| Wellbeing, Inclusion & Safeguarding in Tertiary Education Limited | Health & social care | 2026 |
| Wells Cosmetics Co., Ltd | Wholesale & retail | 2012 |
| Welsh Industrial Partnership (LP) | | 2002 |
| Wendon Limited | Real estate | 1996 |
| Wennalife Beauty Limited | Wholesale & retail | 2025 |
| Wentloog Holdings Limited | Real estate | 2023 |
| Westerheath Limited | Arts & recreation | 1987 |
| Western Imperial Limited | Real estate | 1988 |
| Westgate Commerce Ltd | Wholesale & retail | 2026 |
| Westmore Insure Ltd | Financial services | 2011 |
| Weston Contractors (South Wales) Ltd | Construction | 2003 |
| Weston Moore Limited | Professional & scientific | 2005 |
| Westrike Developments Limited | Hospitality | 1993 |
| Westward House School Limited | Education | 2022 |
| Wheadon Transport Ltd | Transport & logistics | 2022 |
| Whichwood Group Ltd | Administrative & support | 2025 |
| White Finance Solutions Limited | Other services | 2020 |
| Widecov Trades and Investments Limited | Wholesale & retail | 2025 |
| Wild Gaming Limited | Information & communication | 2016 |
| Wildcats Allstars Limited | Arts & recreation | 2023 |
| Williams Firewood Ltd | Construction | 2026 |
| Willmorg Limited | Construction | 2024 |
| Willow Tree Construction and Gardening Ltd | Construction | 2021 |
| Wills and Young Ltd | Real estate | 2019 |
| Wills Consult Ltd | Professional & scientific | 2023 |
| Wilsher Electrical Ltd | Construction | 2024 |
| Wind Comes Ltd | Wholesale & retail | 2024 |
| Windhorse Homes Ltd | Real estate | 2021 |
| Windoor Mate Holdings Ltd | Manufacturing | 2017 |
| Windoor Mate Limited | Manufacturing | 2007 |
| Winsky Trading Limited | Wholesale & retail | 2025 |
| Wirewise Solutions Ltd | Construction | 2026 |
| Wisdom Olive Tree Limited | Financial services | 2026 |
| Wish Upon a Cupcake Limited | Hospitality | 2018 |
| Wishlade Properties Ltd | Real estate | 2026 |
| Wjec Maths Tutoring Ltd | Education | 2025 |
| Wjkk Investments Limited | Construction | 2020 |
| WJP Golf Ltd | Professional & scientific | 2018 |
| WKJ Properties Ltd | Real estate | 2024 |
| WM Estate Holdings Ltd | Real estate | 2022 |
| WMA Holdings Limited | Financial services | 2019 |
| Wmeoi MEW Ltd | Wholesale & retail | 2025 |
| Wntl Limited | Information & communication | 2014 |
| Women's Mind Health UK CIC | Health & social care | 2025 |
| Woodcraft-Co Ltd | Manufacturing | 2022 |
| Woodville Consultants Group Limited | Professional & scientific | 2026 |
| Woodville Consultants Limited | Professional & scientific | 2012 |
| Woodville Consultants NO 2 Limited | Administrative & support | 2020 |
| Workforce Development Wales Ltd | Education | 2015 |
| Worksafepat Ltd | Manufacturing | 2010 |
| Writeoffcheck Ltd | Professional & scientific | 2026 |
| X Beat Yachting Ltd | Arts & recreation | 2011 |
| X Media Limited | Professional & scientific | 2021 |
| Xborder Limited | Wholesale & retail | 2024 |
| Xianglu Technology Co. Ltd | Wholesale & retail | 2025 |
| Xiangyang Wenying Trading Company Limited | Wholesale & retail | 2026 |
| Xindew Co Limited | Wholesale & retail | 2008 |
| Xlnc Vapes Limited | Wholesale & retail | 2022 |
| Xouthbrid Limited | Information & communication | 2025 |
| XVX Ltd | Wholesale & retail | 2025 |
| XZ Property Limited | Real estate | 2025 |
| XZ121 Limited | Hospitality | 2023 |
| Yamihu Co., Ltd | Wholesale & retail | 2025 |
| YAN Tong Chui Ltd | Extraterritorial | 2013 |
| YAY Collective Limited | Administrative & support | 2023 |
| Yellow Diamond Leasing Ltd | Real estate | 2025 |
| Yeoosi International Limited | Wholesale & retail | 2025 |
| Yiwu Fiows Trading Co., Ltd | Wholesale & retail | 2025 |
| Ynysybwl Electrical Services Ltd | Construction | 2024 |
| Ynysybwl Enterprise Programme Limited | Arts & recreation | 2015 |
| Ynysybwl Regeneration Partnership | Administrative & support | 2005 |
| Ynysybwl Rugby Football Community Club Ltd | Arts & recreation | 2022 |
| Yoglod Limited | Wholesale & retail | 2024 |
| Young & Phillips Limited | Professional & scientific | 2004 |
| Your Pontypridd Limited | Other services | 2016 |
| Yummy Beddau Chinese Takeaway Ltd | Hospitality | 2026 |
| Yummy Yummy Beddau Limited | Hospitality | 2021 |
| Yundeng Limited | Professional & scientific | 2016 |
| Yunhong International Trading Co., Limited | Wholesale & retail | 2025 |
| Z33RA Ltd | Hospitality | 2025 |
| Zefh Ltd | Hospitality | 2021 |
| Zenith Print and Packaging Limited | Manufacturing | 1979 |