| Stez Engineering and Construction Services Limited | Construction | 2012 |
| Stock'D Vending Limited | Wholesale & retail | 2026 |
| Stone Court Services Limited | Construction | 2018 |
| Store My Caravan Limited | Real estate | 2019 |
| Stores 4 Floors Limited | Administrative & support | 2015 |
| Story Babies Limited | Education | 2019 |
| Strands Port Talbot Limited | Other services | 2023 |
| Strengthsupply Limited | Health & social care | 2025 |
| Stuart Elliot Consultancy Services Ltd | Professional & scientific | 2016 |
| Styles N Smiles (PT) Limited | Real estate | 2018 |
| Sudden Drop Ltd. | Manufacturing | 2021 |
| Sugarloaf Holdings Ltd | Agriculture & fishing | 2015 |
| Suits Plus Supplies Ltd | Transport & logistics | 1996 |
| Sultan Estates Holding Ltd | Real estate | 2024 |
| Sunkissed Tanning 2 Ltd | Other services | 2024 |
| Sunseekers Port Talbot Limited | Other services | 2019 |
| Suntec Renewables Limited | Energy | 2011 |
| Superior Resin Surfacing Ltd | Construction | 2020 |
| Surf School Wales CIC | Arts & recreation | 2021 |
| Surge Cafe Bar Ltd | Hospitality | 2025 |
| Surveyours Ltd | Information & communication | 2013 |
| SW Accounting Solutions Ltd | Professional & scientific | 2015 |
| SW Autos & Repairs Ltd | Wholesale & retail | 2025 |
| SW Water Ltd | Wholesale & retail | 2023 |
| Swansea Frame Company Ltd | Manufacturing | 2024 |
| Swansea Road Limited | Construction | 2017 |
| Sweatr Ltd | Wholesale & retail | 2026 |
| Sweetman's Ltd | Hospitality | 2021 |
| Swie Holdings Limited | Financial services | 2022 |
| Swift Construction Maintenance Ltd | Construction | 2022 |
| SWS Certification Services Ltd | Administrative & support | 2004 |
| SWS Security Consulting Ltd | Information & communication | 2025 |
| Systemau Perfformiad Limited | Wholesale & retail | 2026 |
| T & J Property Letting Ltd | Real estate | 2018 |
| T & M Haulage Limited | Transport & logistics | 2018 |
| T & T Contractors (Wales) Ltd | Construction | 2018 |
| T Sillman Contracting Ltd | Agriculture & fishing | 2023 |
| T&C Generation Ltd | Real estate | 2018 |
| T.Lang & Sons (Aberavon) Limited | Wholesale & retail | 1954 |
| Tactical TAG UK Ltd | Wholesale & retail | 2023 |
| TAI Auto Ltd | Wholesale & retail | 2013 |
| Taibach Pizza & Kebab Ltd | Hospitality | 2019 |
| Taibach Rugby Football Club Limited | Arts & recreation | 2022 |
| Tajo Sports Ltd | Wholesale & retail | 2023 |
| Talbot Block Limited | Wholesale & retail | 1965 |
| Talbot Holdings Limited | Professional & scientific | 2003 |
| Talent Seekers Agency Ltd | Administrative & support | 2025 |
| Talent Seekers Recruitment Ltd | Administrative & support | 2025 |
| Tata Steel (PT) RFC Limited | Arts & recreation | 2020 |
| Tatami Fightwear Limited | Wholesale & retail | 2009 |
| Taurus Door Systems Ltd | Construction | 2025 |
| Tawe Electrical Limited | Construction | 2023 |
| TDD School of Flowers Ltd | Other services | 2024 |
| Te-Bar Holdings Limited | Manufacturing | 2013 |
| Te-Bar Machine Tool Services Limited | Manufacturing | 2006 |
| Techlok Limited | Manufacturing | 1995 |
| Technical Consultants Reading Ltd | Manufacturing | 1988 |
| Tempertech (Wales) Limited | Manufacturing | 1999 |
| Temple Sales Ltd | Wholesale & retail | 2025 |
| Terence & Company Limited | Health & social care | 2000 |
| Terrahaus Ltd | Construction | 2025 |
| Texturing Technology Limited | Manufacturing | 1992 |
| Tgkn Ltd | Hospitality | 2025 |
| TH3M Limited | Manufacturing | 2019 |
| Thai Corner Limited | Hospitality | 2025 |
| Thai Spice Kitchen Ltd | Hospitality | 2026 |
| Thanthondrianjaneyar Sithapeedam Ltd | Other services | 2013 |
| Thas Convenience Store Ltd | Wholesale & retail | 2026 |
| That Italian Kitchen Ltd | Hospitality | 2024 |
| THE Party Shop (Pencoed) Ltd | Wholesale & retail | 2012 |
| THE 9 Darter 501 Ltd | Wholesale & retail | 2026 |
| THE Bengal's Pride Foundation Ltd | Professional & scientific | 2021 |
| THE Big P Project Ltd | Wholesale & retail | 2022 |
| THE Bunny Coffee Company Ltd | Hospitality | 2020 |
| THE Caff at Ptbc Ltd | Hospitality | 2024 |
| THE Chocolate Factory Tours Limited | Arts & recreation | 2002 |
| THE Coed ERW Company Limited | Households | 1995 |
| THE Construction Club Ltd | Professional & scientific | 2022 |
| THE Copper Collaborative Ltd | Information & communication | 2018 |
| THE Dancing Daffodil Hire Ltd | Administrative & support | 2025 |
| THE Dancing Daffodil Ltd | Wholesale & retail | 2018 |
| THE Decades Band Ltd | Arts & recreation | 2014 |
| THE Docks Cafe Ltd | Hospitality | 2025 |
| THE Flower Box (Port Talbot) Limited | Wholesale & retail | 2010 |
| THE Garden Pair Ltd | Administrative & support | 2025 |
| THE Golden Valley BEE Company Limited | Manufacturing | 2021 |
| THE Grand Hotel (Port Talbot) Limited | Hospitality | 2019 |
| THE Great British Manufacturing Group Ltd | Manufacturing | 2016 |
| THE Grill HUT Swansea Ltd | Hospitality | 2018 |
| THE Heycock Foundation | Education | 2006 |
| THE Hideout Aberavon Limited | Hospitality | 2023 |
| THE Holms Paper Company Limited | | 1984 |
| THE Jones Edit Limited | Hospitality | 2025 |
| THE Luxury Lifestyle Agency Limited | Other services | 2020 |
| THE Natural Play Company Limited | Extraterritorial | 2011 |
| THE Oaks Respite Services Ltd | Health & social care | 2022 |
| THE Overseas Property Agency Limited | Real estate | 2003 |
| THE Painterman Limited | Construction | 2025 |
| THE Parade (Neath) Limited | Hospitality | 2017 |
| THE Party House (UK) Ltd | Wholesale & retail | 2008 |