| T.S.G Jones Construction Ltd | Construction | 2023 |
| T.Stone Travel Ltd | Transport & logistics | 2021 |
| T.Trumper Limited | Administrative & support | 2012 |
| T2 Linguistics Ltd | Professional & scientific | 1992 |
| T2 Property Group Ltd | Real estate | 2026 |
| TA Carpentry & Joinery Ltd | Manufacturing | 2025 |
| TA MED Holdings Ltd | Health & social care | 2024 |
| TA TEC Limited | Information & communication | 2019 |
| TA White Ltd | Health & social care | 2022 |
| TAB Holdings Ltd | Financial services | 2023 |
| Tadcu Productions Ltd. | Information & communication | 2025 |
| Tafarn Y Piod Management Company Ltd | Administrative & support | 2018 |
| Taffod Seafarers Limited | Manufacturing | 2017 |
| Taffpop Limited | Information & communication | 2014 |
| Taffy Dakar CIC | Hospitality | 2024 |
| Taffy's Swansea Ltd. | Real estate | 1994 |
| Taffys Woodfield Street Ltd | Other services | 2018 |
| TAG Apparel Group Ltd | Wholesale & retail | 2020 |
| TAG Controls & Automation Limited | Manufacturing | 2012 |
| TAG Precision Engineering Limited | Manufacturing | 2021 |
| TAG Security Limited | Administrative & support | 2024 |
| TAG Security/Recovery Limited | Administrative & support | 2000 |
| Tahir Homes Limited | Real estate | 2021 |
| TAI Dinas Limited | Real estate | 2016 |
| TAI Turner Limited | Construction | 2026 |
| Tailored Financial Advice Ltd | Financial services | 2016 |
| Tailored Learning Limited | Education | 2021 |
| Tajs Properties Limited | Real estate | 2024 |
| Take ME to the Manor Limited | Hospitality | 2021 |
| Takumi Sushi& Noodle Bar Limited | Hospitality | 2019 |
| TAL Y Coed Associates Ltd | Hospitality | 2021 |
| Talent Cube Limited | Professional & scientific | 2013 |
| Talentscape Limited | Professional & scientific | 2016 |
| Talfan Farms Ltd | Agriculture & fishing | 2017 |
| Taliesin Engineering Ltd | Professional & scientific | 2022 |
| Talis Consulting Limited | Health & social care | 2002 |
| Talking Space Swansea Limited | Health & social care | 2024 |
| Tallon Enterprises Ltd | Information & communication | 2017 |
| Talsin Limited | Construction | 2016 |
| TAM Gofal Ltd | Health & social care | 2023 |
| Tama Tribe Community in the UK Ltd | Other services | 2012 |
| Tamil Ltd | Wholesale & retail | 2025 |
| Tamil Pages Limited | Information & communication | 2002 |
| TAN DU RUM Ltd | Wholesale & retail | 2025 |
| TAN YR Allt House Limited | Health & social care | 2004 |
| TAN YR Allt Lodge Limited | Health & social care | 2011 |
| Tanc & Distyll Beverage Co Ltd | Hospitality | 2025 |
| Tangled RAT Ltd | Other services | 2016 |
| Tangleroot 2 Ltd | Other services | 2017 |
| Tanja Beetz Limited | Hospitality | 2026 |
| Tank Farm Road 2 Limited | Real estate | 2026 |
| Tank Farm Road Limited | Real estate | 2026 |
| Tannery Yard Management Limited | Real estate | 2000 |
| Tantempleton Ltd | Transport & logistics | 2022 |
| Tanvir Associates Ltd | Education | 2022 |
| Tanvir Ltd | Real estate | 2019 |
| Tanya Link Productions Limited | Arts & recreation | 2015 |
| Taoa Creates Limited | Arts & recreation | 2020 |
| Taoa Studio Limited | Arts & recreation | 2012 |
| Tapas & GIN House Ltd | Hospitality | 2020 |
| Tapestart Limited | Real estate | 1990 |
| Taplight Limited | Other services | 1995 |
| Tara Hammett Coaching Limited | Arts & recreation | 2021 |
| Tara Hammett Online Limited | Wholesale & retail | 2018 |
| Taran Recruitment Services Limited | Administrative & support | 2003 |
| Tarar Plastic Surgery Limited | Health & social care | 2026 |
| Tarbiyah Travel & Tours Ltd | Administrative & support | 2025 |
| Target Aerials (Swansea) | Wholesale & retail | 1986 |
| Targetlocal Limited | Arts & recreation | 1991 |
| Tarian Labs Ltd | Information & communication | 2025 |
| Tarka Express Ltd | Hospitality | 2024 |
| Tarkaa Ltd | Hospitality | 2020 |
| Tarker Cine Holdings Ltd | Arts & recreation | 2019 |
| Tarquin Earl Ltd | Financial services | 2017 |
| Tartan Centre (Wales) Ltd | Wholesale & retail | 2014 |
| Tasan Ltd | Wholesale & retail | 2017 |
| Task My JOB Ltd | Information & communication | 2026 |
| Taste T UN Limited | Hospitality | 2025 |
| Tatws Poeth Limited | Administrative & support | 2023 |
| Tatws Poeth Properties Limited | Real estate | 2024 |
| Taurho Transcribes Limited | Information & communication | 2016 |
| Taurus Electrical Services Ltd | Construction | 2023 |
| Tawe Coast Properties Limited | Real estate | 2015 |
| Tawe Holdings Limited | Real estate | 2024 |
| Tawe Homes Ltd | Extraterritorial | 2024 |
| Tawe Imaging Ltd | Health & social care | 2015 |
| Tawe MOT & Repair Centre Ltd | Wholesale & retail | 2018 |
| Tawe Scaffolding & Engineering Ltd | Construction | 2023 |
| Tawe Services Limited | Administrative & support | 2003 |
| Tawe Timber Limited | Wholesale & retail | 1984 |
| Tawe Trading Limited | Wholesale & retail | 2014 |
| Tawe Vapours Limited | Wholesale & retail | 2015 |
| Tawe View RTM Company Ltd | Households | 2019 |
| Tawemedia Limited | Information & communication | 2007 |
| Tawesoft Ltd | Information & communication | 2015 |
| Tax CAN BE Limited | Extraterritorial | 2014 |
| Tax Claim Solutions Ltd | Other services | 2021 |
| Tax, Asset & Commercial Strategies Ltd | Professional & scientific | 2019 |
| Taxi's Direct (UK) Limited | Wholesale & retail | 2001 |
| Taydav Ltd | Wholesale & retail | 2025 |