| Vision Comms (Wales) Limited | Information & communication | 2013 |
| Voltsecure Ltd | Construction | 2021 |
| Volume Planning & Developments Limited | Professional & scientific | 2013 |
| Voyage Adventure Vans Limited | Wholesale & retail | 2021 |
| Vwservices Limited | Administrative & support | 2025 |
| W R Forecourt Retail Ltd | Wholesale & retail | 2015 |
| W&W Tuition LP | | 2020 |
| W2 Window Systems Limited | Construction | 2022 |
| Walters and Brailsford Treeworks Ltd | Administrative & support | 2024 |
| Warner Howard (Holdings) Limited | Professional & scientific | 2000 |
| Warner Howard (UK) Limited | Professional & scientific | 1967 |
| Warner Howard Group Limited | Professional & scientific | 2000 |
| Warner Howard Limited | Professional & scientific | 1960 |
| Warner Howard Services Limited | Professional & scientific | 2000 |
| Warranty Group Limited | Other services | 2020 |
| Wasser Werk Limited | Administrative & support | 2013 |
| Watford Heating Service Co. Ltd | Manufacturing | 2009 |
| Watkins Estate Agents Limited | Real estate | 2018 |
| Watkins Lettings & Property Management Limited | Real estate | 2026 |
| Watkins Removals & Storage Ltd | Transport & logistics | 2024 |
| Wave Environmental Solutions Ltd | Water & waste | 2016 |
| Waypoint Trading Ltd | Wholesale & retail | 2016 |
| Webinning Limited | Wholesale & retail | 2017 |
| Webolific Ltd | Information & communication | 2023 |
| Webspace World Limited | Information & communication | 2000 |
| Wedding Gems Corporate Limited | Other services | 2022 |
| Wedding Gems Ltd | Other services | 2019 |
| Wenjuan Limited | Wholesale & retail | 2023 |
| Wesbry 01 Ltd | Hospitality | 2012 |
| Wesbry 03 Ltd | Extraterritorial | 2014 |
| Western Motors Limited | Wholesale & retail | 2019 |
| Weston & Elliott Ltd | Real estate | 2016 |
| Weston Holdings Limited | Financial services | 2020 |
| Wgwh Limited | Wholesale & retail | 2025 |
| What Where When (Cardiff) Limited | Health & social care | 2006 |
| Whfp Limited | Construction | 2026 |
| Whitey Properties Limited | Construction | 2018 |
| Whitney Strategy Group Ltd | Wholesale & retail | 2026 |
| WI Carpentry Limited | Manufacturing | 2020 |
| Wilcox Professional Business Services Ltd | Extraterritorial | 2017 |
| Wild Rock Glamping Ltd | Hospitality | 2022 |
| Wild Rock Holdings Ltd | Financial services | 2025 |
| Wilde Posies Ltd. | Wholesale & retail | 2020 |
| William and Daughters Property Sales Ltd | Real estate | 2018 |
| Williams & Elliott Ltd | Real estate | 2021 |
| Williams & LEE Property Developments Ltd | Real estate | 2025 |
| Willtech Systems Ltd | Construction | 2025 |
| Wilstaff PT Company Limited | Extraterritorial | 2023 |
| Wimtec Environmental Limited | Professional & scientific | 1995 |
| Windata Limited | Professional & scientific | 2012 |
| Windcat Workboats (Wales) CYF | Professional & scientific | 2013 |
| Windows Gleaming Ltd | Administrative & support | 2018 |
| Windsor Motors Ltd | Wholesale & retail | 2021 |
| Wing FIN Limited | Hospitality | 2026 |
| Wingfield Tyres Ltd | Wholesale & retail | 2025 |
| Wipeout Cleaning Services Ltd | Administrative & support | 2015 |
| WMS Contractors Limited | Construction | 2024 |
| Wolf Construction and Brickwork Limited | Construction | 2025 |
| Women Wellbeing Walks Caerphilly CIC | Health & social care | 2026 |
| Wonkydoolah Limited | Professional & scientific | 2024 |
| Wood Chill CIC | Health & social care | 2024 |
| Woodpecker Air.Com Ltd | Transport & logistics | 2017 |
| Woodpecker Trading Co Limited | Wholesale & retail | 1996 |
| Worksmart Business Services Limited | Professional & scientific | 2026 |
| WP Creations Ltd | Manufacturing | 2025 |
| WPR Trade Limited | Health & social care | 2011 |
| Wright Car Sales Ltd | Wholesale & retail | 2024 |
| Writers' Cwtch Limited | Education | 2016 |
| XL Metals & Catalysts Limited | Wholesale & retail | 2022 |
| Y Brynau Investments Limited | Real estate | 2023 |
| Y Prennydd CYF | Administrative & support | 2025 |
| Y&M Car Wash Ltd | Administrative & support | 2024 |
| Yadh Education & Events Services (YES) C.I.C. | Education | 2023 |
| Yalarosa Limited | Professional & scientific | 2011 |
| YBR Groundwork’S (South Wales ) Limited | Other services | 2018 |
| Yellow Brick Consultancy Limited | Professional & scientific | 2023 |
| Yellow Square Enterprises Ltd | Wholesale & retail | 2015 |
| YMZ & P Ltd | Hospitality | 2024 |
| Your Cube Ltd | Construction | 2022 |
| Your Forever Home Limited | Construction | 2021 |
| Your Tech Trader Limited | Wholesale & retail | 2016 |
| Ysgol Court Flats Limited | Real estate | 2022 |
| Yuvicorn Ltd | Administrative & support | 2025 |
| Zaxo Cardiff Ltd | Administrative & support | 2024 |
| Zenith Print (UK) Limited | Professional & scientific | 1986 |
| Zest Recruitment and Legal Consultancy Limited | Professional & scientific | 2017 |
| ZLJ Group Ltd | Professional & scientific | 2026 |
| Zola Building Services Limited | Construction | 2024 |
| ZPN Power Developments Ltd | Manufacturing | 2024 |
| Zumee Ltd | Information & communication | 2019 |