| Sucatas Gana Pecas Usadas Ltd | Wholesale & retail | 2017 |
| Sudzz Exterior Cleaning Solutions Ltd | Administrative & support | 2025 |
| Sugar Melon Ltd | Wholesale & retail | 2019 |
| Sulaco Drive Ltd | Transport & logistics | 2025 |
| Summit Assure Consultancy Limited | Professional & scientific | 2025 |
| Sun WAH 888 Ltd | Hospitality | 2025 |
| Sunay Fast Food Ltd | Hospitality | 2024 |
| Sunbury Warehousing & Logistics Limited | Transport & logistics | 2014 |
| Sunhill Developments (NW) Ltd | Construction | 2012 |
| Sunnyridge Properties Ltd | Real estate | 2021 |
| Sunrhos Ltd | Hospitality | 2011 |
| Sunshine Bars Rhos Limited | Other services | 2020 |
| Sunsynk Group Limited | Financial services | 2023 |
| Sunsynk Mobile Limited | Manufacturing | 2022 |
| Supacivil Resin Limited | Construction | 2023 |
| Super Car Wash Denbigh Ltd | Administrative & support | 2025 |
| Super Suds Limited | Administrative & support | 2026 |
| Superhero Investments Limited | Financial services | 2019 |
| Superies Limited | Information & communication | 2026 |
| Superior Garage Doors Ltd | Construction | 2026 |
| Supersonic Ltd | Manufacturing | 2026 |
| Supplydivision Limited | Wholesale & retail | 2003 |
| Supreme Klean Ltd | Other services | 2008 |
| Supreme Sanding Solutions Ltd | Construction | 2023 |
| Sure Signs Holdings Limited | Financial services | 2025 |
| Sure Signs UK Ltd | Professional & scientific | 2003 |
| Sutton Green Engineering Limited | Professional & scientific | 2024 |
| SVA Taxi Ltd | Transport & logistics | 2025 |
| Svmlm Ltd | Real estate | 2026 |
| SVP Venues Ltd | Hospitality | 2025 |
| SW Plumbing and GAS Services Ltd | Construction | 2021 |
| Swager Hoses Ltd | Other services | 2017 |
| Swain Properties Limited | Real estate | 2014 |
| Sweet Grind Ltd | Manufacturing | 2025 |
| Swif-Debt Area B LP | | 2023 |
| Swift Drone Services Ltd | Professional & scientific | 2025 |
| Swift Skyline Limited | Real estate | 2017 |
| Swiftform Concrete Designs Limited | Manufacturing | 1985 |
| Swifty Studios Ltd | Information & communication | 2024 |
| Swingzfx Ltd | Financial services | 2025 |
| Switchgear Installations Ltd | Construction | 2024 |
| SY Menopause Solutions Ltd | Health & social care | 2025 |
| Sybotts Grange Management Company Limited | Households | 2024 |
| Sylvia Dusty Fairy Ltd | Administrative & support | 2021 |
| Sylvian Logistics Limited | Transport & logistics | 2017 |
| Synovium UK Ltd | Wholesale & retail | 2018 |
| Syrencot Limited | Hospitality | 2018 |
| Systechit Technology Ltd | Information & communication | 2013 |
| Syzygy Building Consultancy Ltd | Professional & scientific | 2023 |
| Szab Engineering Limited | Professional & scientific | 2019 |
| Szkola the Best Limited | Education | 2025 |
| Szukala Properties Ltd | Real estate | 2025 |
| T & T Osilaja Limited | Health & social care | 2019 |
| T B Electronics Ltd | Manufacturing | 2019 |
| T Brown Cymru Ltd | Professional & scientific | 2012 |
| T H & G Jones Ltd | Transport & logistics | 2025 |
| T J Crane Hire Limited | Administrative & support | 2004 |
| T L Design Limited | Professional & scientific | 2012 |
| T T Hall Plumbing and Heating Limited | Construction | 2002 |
| T T Plumbing & Heating Solutions Ltd | Construction | 2024 |
| T Walsh Consulting Limited | Information & communication | 2016 |
| T&D Couriers Limited | Transport & logistics | 2025 |
| T. LL. Morrison (Wrexham) Limited | Construction | 1975 |
| T.Bowler Ltd | Wholesale & retail | 2022 |
| T.S. Perry (Roofing Specialists) Limited | Construction | 2009 |
| T4 Cartridges Ltd | Wholesale & retail | 2025 |
| T8 Creative Ltd | Professional & scientific | 2025 |
| Tabletaps Ltd | Wholesale & retail | 2021 |
| Tabley Sporting Club Ltd | Arts & recreation | 2025 |
| Tackle Temple Ltd | Wholesale & retail | 2023 |
| Tacp Architects Ltd | Professional & scientific | 2011 |
| Tacp Holdings Limited | Financial services | 2023 |
| TAD Living Ltd | Wholesale & retail | 2021 |
| Tafara Care Services Ltd | Administrative & support | 2014 |
| TAG Active Limited | Arts & recreation | 2015 |
| Tageu Limited | Information & communication | 2022 |
| Tailored Laser and Fabrications Ltd | Manufacturing | 2024 |
| Tailormade Escapes Ltd | Administrative & support | 2024 |
| Take Care Home Care Limited | Health & social care | 2011 |
| Take Two Hair Design Limited | Other services | 2013 |
| Talabe Ltd | Agriculture & fishing | 2025 |
| Talbot Scaffolding Limited | Construction | 2022 |
| Talisman Estates Limited | Real estate | 2025 |
| Talking Planet Limited | Education | 2025 |
| Talwrn Farms Ltd | Agriculture & fishing | 2015 |
| Tan-Y-Clawdd Motors Limited | Wholesale & retail | 1982 |
| Tangent Lines Ltd | Administrative & support | 2011 |
| Tank Fitters Ltd | Manufacturing | 2015 |
| Tanker Safe UK Ltd | Wholesale & retail | 2025 |
| TAP the App Limited | Transport & logistics | 2018 |
| Tapas Restaurants Ltd | Hospitality | 2026 |
| Taram Tradings Ltd | Wholesale & retail | 2024 |
| Taran Events Limited | Hospitality | 2023 |
| Target Markets Ltd | Financial services | 2026 |
| Target Master Limited | Arts & recreation | 2025 |
| Tastebudds Limited | Information & communication | 2016 |
| Tavonga Ltd | Health & social care | 2013 |
| TAY & TIG Properties Ltd | Real estate | 2025 |
| Taylor Groundworks Ltd | Manufacturing | 2014 |
| Taylor Made Joinery Services Ltd | Construction | 2026 |