| Smash Rebel Ltd | Hospitality | 2026 |
| SMM DAS Ltd | Real estate | 2026 |
| Snooker Loopy Ltd | Wholesale & retail | 2026 |
| Sonzai Ltd | Wholesale & retail | 2021 |
| Split Screen Stiwdio Ltd | Information & communication | 2025 |
| Splott Holdings Ltd | Real estate | 2026 |
| Spuds by the Sea Ltd | Hospitality | 2026 |
| Squaredmind Ltd | Professional & scientific | 2026 |
| Ss&S Contractors Ltd | Construction | 2022 |
| Stainedglassfraser Ltd | Information & communication | 2026 |
| Starlight Stays Property Management Limited | Hospitality | 2025 |
| Starlightstayspropertysourcing Limited | Real estate | 2025 |
| Stars World Ltd | Wholesale & retail | 2026 |
| Stayready Property Services Ltd | Real estate | 2026 |
| Stilo’S Painting and Decorating Ltd | Construction | 2025 |
| Suburban Collective Ltd | Wholesale & retail | 2026 |
| Summit Energies Limited | Energy | 2014 |
| Supastrikers Cardiff Limited | Arts & recreation | 2021 |
| Superwild Ltd | Wholesale & retail | 2026 |
| Surcedbycj Limited | Hospitality | 2025 |
| Surge Electrical, Fire & Security Ltd | Professional & scientific | 2025 |
| Swadx Limited | Hospitality | 2026 |
| Swdrilining Ltd | Construction | 2025 |
| Swes Electrical Ltd | Construction | 2025 |
| Swift Half Limited | Hospitality | 2023 |
| Switch Spaces Limited | Real estate | 2026 |
| Swoop Cars Ltd | Transport & logistics | 2026 |
| Talon Cymru Cyfyngedig | Information & communication | 1996 |
| Tarian Consult Ltd | Professional & scientific | 2018 |
| TDL Commerce Ltd | Wholesale & retail | 2025 |
| Teddys Place Ltd | Information & communication | 2022 |
| Teemis Ltd | Construction | 2020 |
| Teri OAT UK Ltd | Real estate | 2020 |
| Terramar Networks Limited | Information & communication | 2009 |
| Terrenceblakefaith Ltd | Real estate | 2023 |
| Testun Cyfyngedig | Information & communication | 1994 |
| Tgnd Business Academy Ltd | Wholesale & retail | 2025 |
| THE Business Planet Ltd | Wholesale & retail | 2025 |
| THE Dahan Collection Limited | Real estate | 2025 |
| THE Grand Naan Curry House Ltd | Hospitality | 2023 |
| THE Living Looms Ltd | Wholesale & retail | 2024 |
| THE Mushroom Gentleman Ltd | Agriculture & fishing | 2025 |
| THE Scrub Sisters Ltd | Administrative & support | 2026 |
| THE Skin Studio Cardiff Ltd | Other services | 2024 |
| THE Street Wise Intelligence Group Ltd | Information & communication | 2026 |
| Thomas Phillips Ltd | Professional & scientific | 2024 |
| Tiff’S Task Angels Ltd | Manufacturing | 2026 |
| Tile & Bath Co (UK) Ltd | Wholesale & retail | 2006 |
| TME Carpentry Ltd | Extraterritorial | 2024 |
| Tmma Estates Ltd | Real estate | 2026 |
| Tongwynlais TAP Ltd | Wholesale & retail | 2026 |
| Top Notch Records Ltd | Manufacturing | 2026 |
| Touch of Sparkle Clean Ltd | Administrative & support | 2026 |
| TRI 3 Ltd | Construction | 2023 |
| Tribal Nation Entertainment Ltd | Wholesale & retail | 2026 |
| Tricloud Tech Ltd | Information & communication | 2025 |
| Triple-F Global Ltd | Wholesale & retail | 2026 |
| True Rest Stays Ltd | Real estate | 2026 |
| TS Bedi Ventures Ltd | Wholesale & retail | 2026 |
| TTS Cardiff Ltd | Hospitality | 2023 |
| Turbo Wealth Ltd | Professional & scientific | 2026 |
| Tutela DRS Ltd | Administrative & support | 2025 |
| Tutorful Minds Ltd | Education | 2023 |
| Twilight Stays Limited | Real estate | 2025 |
| Two Way Consultancy Ltd | Hospitality | 2026 |
| TY Coch Media Ltd | Information & communication | 2019 |
| TYN Y Caeau Farm Ltd | Agriculture & fishing | 2024 |
| Uhnwichef Ltd | Administrative & support | 2026 |
| UK Business Connections Limited | Extraterritorial | 2009 |
| UK Driver Medicals Ltd | Health & social care | 2026 |
| UK Fintech Limited | Wholesale & retail | 2025 |
| UMR Properties Ltd | Real estate | 2025 |
| Unipilot Ltd | Information & communication | 2025 |
| Urbanpoint Facilities Limited | Construction | 2026 |
| Vakaj Ltd | Transport & logistics | 2026 |
| Valleys ALE Trails - Llwybrau Cwrw Y Cymoedd CYF. | Administrative & support | 2017 |
| Vapour Chain Limited | Arts & recreation | 2025 |
| Vellora Properties Limited | Hospitality | 2026 |
| Veloria Beauty Ltd | Wholesale & retail | 2026 |
| Venturacv Ltd | Information & communication | 2025 |
| Vickoprimesupport Ltd | Health & social care | 2026 |
| Victel Mechanical Solutions Ltd | Professional & scientific | 2026 |
| Visuals by Moiz Ltd | Information & communication | 2025 |
| VPN Realtors Ltd | Real estate | 2025 |
| W2WC Film Ltd | Information & communication | 2026 |
| Walix Ltd | Administrative & support | 2024 |
| WEG Solar Ltd | Construction | 2024 |
| Welshandrehab Ltd | Health & social care | 2026 |
| WFM Ltd | Information & communication | 2025 |
| Whitchurch Medical Aesthetics Ltd | Health & social care | 2024 |
| Wilbur Thomas Ltd | Real estate | 2020 |
| Will Authority Limited | Extraterritorial | 2021 |
| Wills Finance Ltd | Professional & scientific | 2026 |
| Xylo Trading Ltd | Wholesale & retail | 2025 |
| Y Brifwyl CYF | Arts & recreation | 2005 |
| Yates UK Property Group Ltd | Construction | 2026 |
| Yemdam Ltd | Wholesale & retail | 2026 |
| Yesno Ltd | Extraterritorial | 2013 |
| Ynni Glan Cyfyngedig | Professional & scientific | 2006 |
| Younique Services & Products Ltd | Manufacturing | 2023 |