| Waltwood Management Services Ltd | Professional & scientific | 2014 |
| Wamo! Healthcare Ltd | Arts & recreation | 2024 |
| Wantu Wantu Ltd | Administrative & support | 2023 |
| WAO Investments Limited | Extraterritorial | 2021 |
| Ward Sports Group Limited | Arts & recreation | 2025 |
| Warden Hill (Totland Bay IW) Management Company Limited | Professional & scientific | 2002 |
| Wares Engineering Limited | Manufacturing | 2014 |
| Warhorse Records Limited | Information & communication | 2020 |
| Wario's Installations Ltd | Construction | 2018 |
| Warmer Living Maintenance Limited | Construction | 2017 |
| Warmer Wise Limited | Construction | 2025 |
| Warne Insulation Limited | Construction | 2025 |
| Warren Peace Pitt Media Ltd | Information & communication | 2017 |
| Wassist Ltd | Information & communication | 2013 |
| Waste Lubricating Oils Limited | Water & waste | 2021 |
| Wasup Limited | Wholesale & retail | 2016 |
| Watchbell House Natural Therapy Centre Limited | Other services | 2016 |
| Watcheroo Ltd | Administrative & support | 2016 |
| Watches UK NO1 Limited | Wholesale & retail | 2022 |
| Water Marc Limited | Agriculture & fishing | 2002 |
| Water Mill Pottery Limited | Administrative & support | 2004 |
| Water Mill Vacations Ltd | Hospitality | 2022 |
| Water Treatment Products Holdings Limited | Financial services | 2016 |
| Water Treatment Products Limited | Water & waste | 1999 |
| Waterborn Environmental Limited | Administrative & support | 2012 |
| Waterhouse & Sons Ltd | Real estate | 2026 |
| Waterlaw Limited | Real estate | 1991 |
| Waterloo Hotel Newport Ltd | Hospitality | 2021 |
| Waterloo House Refurbishments Ltd | Construction | 2020 |
| Waterloo Inn 2023 Limited | Hospitality | 2023 |
| Waterloo Residual Land Limited | Households | 2017 |
| Watermere Ltd | Hospitality | 2017 |
| Waternay House Ltd | Real estate | 2024 |
| Waterside Court Property Limited | Extraterritorial | 2014 |
| Waterside Magor Ltd | Hospitality | 2009 |
| Watertight Plumbing Solutions Limited | Construction | 2013 |
| Watertite Plumbing & Heating Limited | Construction | 2008 |
| Waterview Park Limited | Financial services | 2020 |
| Watkin Davies Limited | Wholesale & retail | 1963 |
| Wattif Limited | Professional & scientific | 2026 |
| Watts Building Contractors Limited | Construction | 2022 |
| Watts Electrical Engineering Ltd | Construction | 2019 |
| Watts UP Media Limited | Information & communication | 2024 |
| Wattsup Electrical IOW Ltd | Construction | 2024 |
| Wave Machine Ltd | Information & communication | 2019 |
| Wave Media Partners Limited | Administrative & support | 1996 |
| Waverley Inn IOW Ltd | Hospitality | 2022 |
| Way KAY Kitchen Limited | Hospitality | 2024 |
| Waybridge Ltd | Information & communication | 2019 |
| Wayman Schwartz Limited | Real estate | 2021 |
| Waypoint Games Ltd | Information & communication | 2025 |
| Wazny Solutions Ltd | Construction | 2019 |
| WB Wales S.W Limited | Education | 2015 |
| WBI Holdings Limited | Extraterritorial | 2016 |
| WCC Clothing Ltd | Wholesale & retail | 2025 |
| Wchr Limited | Real estate | 2018 |
| WD Retail Consultancy Limited | Professional & scientific | 2020 |
| WE Care Properties Limited | Real estate | 2021 |
| WE Fit Tyres Ltd | Wholesale & retail | 2023 |
| WE GOT YOU Covered Roofing and Guttering Ltd | Construction | 2025 |
| WE Hire Holdings Ltd | Financial services | 2022 |
| WE Hire Ltd | Construction | 2026 |
| We'Re OUT of Office Ltd | Professional & scientific | 2025 |
| WE3 Property Services Limited | Real estate | 2014 |
| Weare Property Development Ltd | Construction | 2020 |
| Wearexp Ltd | Wholesale & retail | 2024 |
| Weavico Ltd | Wholesale & retail | 2025 |
| Web 4 Ltd | Information & communication | 2011 |
| Web 4 US Limited | Information & communication | 2011 |
| Webb Jenkins (IW) Limited | Real estate | 2010 |
| Webber Design Limited | Professional & scientific | 2010 |
| Wecancare Ltd | Health & social care | 2026 |
| Weddings Events Wales Ltd | Other services | 2020 |
| Weklean South Wales Ltd | Administrative & support | 2021 |
| Welby Hall Ltd | Wholesale & retail | 2017 |
| Welcome Home Lettings Ltd | Real estate | 2014 |
| Welding and Cutting Machinery (Cwmbran) Limited | Manufacturing | 1981 |
| Well Investments Ltd | Real estate | 2022 |
| Well Wood Reflexology Limited | Other services | 2023 |
| Wellbrit Ltd | Manufacturing | 2022 |
| Wellies Farm & Garden CIC | Education | 2021 |
| Wellwood House Residents Association (I.W.) Limited | Households | 1996 |
| Welsh Bengals Sporting Club CIC | Education | 2025 |
| Welsh Cycling Union Limited | Arts & recreation | 2002 |
| Welsh Flip Factory Ltd | Real estate | 2025 |
| Welsh Independent Schools Council | Education | 2010 |
| Wemo Technologies Limited | Transport & logistics | 2013 |
| Wenallt Farm Limited | Agriculture & fishing | 2005 |
| Wendy Shatford Coaching Ltd | Professional & scientific | 2023 |
| Wentlooge Investments Ltd | Real estate | 2019 |
| Wentlooge Rentals Ltd | Real estate | 2023 |
| Wentwood Design & Build Limited | Construction | 2017 |
| Wentwood Estates Limited | Agriculture & fishing | 2026 |
| Wentwood Handling Ltd | Administrative & support | 2009 |
| Wentwood House Limited | Real estate | 2022 |
| Wentwood Solutions Limited | Other services | 2006 |
| Wesgate Automotive Limited | Wholesale & retail | 2019 |
| Wesgate Performance Ltd | Wholesale & retail | 2021 |
| Wesley Clover Wales Limited | Financial services | 2001 |
| Wesley Consulting Cyfyngedig | Professional & scientific | 2024 |