| Systech GB Limited | Information & communication | 2001 |
| T & L Contracting Support Limited | Administrative & support | 2007 |
| T & M Food Supplies Ltd | Hospitality | 2023 |
| T Buchanan Limited | Professional & scientific | 2022 |
| T E K Structures Limited | Construction | 2007 |
| T G D Landscape Limited | Professional & scientific | 2003 |
| T Geldart Limited | Health & social care | 2013 |
| T P Watts Plumbing Services Limited | Construction | 2004 |
| T W Installations Ltd | Construction | 2020 |
| T&K Smart Repairs Ltd | Wholesale & retail | 2021 |
| T&P Optics Ltd | Hospitality | 2025 |
| T.E.N. Delivery Services Limited | Information & communication | 2016 |
| T20 Communications Limited | Financial services | 2021 |
| Taada Holdings Limited | Financial services | 2025 |
| Table & Chai Ltd | Extraterritorial | 2024 |
| Tabs Logistics Limited | Transport & logistics | 2021 |
| Tabula Rasa Group Ltd | Wholesale & retail | 2024 |
| Tadley Acres (Live/Work) Management Limited | Households | 2005 |
| Tafelberg Holdings Ltd | Wholesale & retail | 2021 |
| TAICHI4HEALTHANDWELLBEING Limited | Extraterritorial | 2013 |
| Tailor Made Holdings Ltd | Professional & scientific | 2002 |
| Tailor Made Kitchens Limited | Administrative & support | 2000 |
| Takamaka Holdings Ltd | Real estate | 2021 |
| Takamaka Ltd | Construction | 2018 |
| Takeout Spice Ltd | Real estate | 2024 |
| Takeovr Ltd | Hospitality | 2026 |
| Talamac Ltd | Construction | 2023 |
| Taleniq Ltd | Administrative & support | 2019 |
| Talent Locker Projects Limited | Information & communication | 2022 |
| Talent Sure Recruitment Limited | Administrative & support | 2013 |
| Tales of Humanity Ltd | Professional & scientific | 2023 |
| Talisman Homes (West) Limited | Construction | 1986 |
| Talisman Homes Limited | Construction | 1992 |
| Talk the Lingo Ltd | Professional & scientific | 2021 |
| Tamlyn Creative Limited | Professional & scientific | 2017 |
| Tandrust Ltd | Health & social care | 2019 |
| Tanglefoot Farm Livery Limited | Agriculture & fishing | 2020 |
| Tangmere Dental Care Ltd | Health & social care | 2011 |
| Tangmere Tdmp Holding Limited | Financial services | 2024 |
| Tanya’S Cleaners Franchise Ltd | Professional & scientific | 2022 |
| Taongatapiwa Limited | Health & social care | 2019 |
| TAP Group Limited | Professional & scientific | 2005 |
| Taplow Riverside Management Company Limited | Households | 2016 |
| Tapping the Source Ltd | Wholesale & retail | 2017 |
| Tarakasi Ltd | Wholesale & retail | 2024 |
| Tarsius Ltd | Real estate | 2017 |
| TAS 0100 Limited | Financial services | 2022 |
| TAS 0200 Limited | Financial services | 2024 |
| Taskcastle Limited | Construction | 2011 |
| Taste IT Takeaway Ltd | Hospitality | 2018 |
| Tatted UP Kitchen Ltd | Hospitality | 2025 |
| Tattva Ventures Limited | Financial services | 2025 |
| TAU Engineering Limited | Administrative & support | 2013 |
| TAU Learning LAB Ltd | Education | 2022 |
| Taylor Lewis Cottages Limited | Hospitality | 2019 |
| Taylor Made Tyres (Southampton) Limited | Wholesale & retail | 2015 |
| Taylor VET Specialists Ltd | Professional & scientific | 2011 |
| Taylor-Made Landscapes (Hants) Limited | Administrative & support | 2018 |
| TC Cleaning Machines Ltd | Extraterritorial | 2015 |
| TC Fair Oak Ltd | Other services | 2023 |
| Tdmp Five Limited | Health & social care | 2023 |
| Tdmp Four Limited | Health & social care | 2022 |
| Tdmp Seven Limited | Financial services | 2024 |
| Tdmp Seven Midco Limited | Financial services | 2024 |
| Tdmp SIX Limited | Health & social care | 2024 |
| Tdmp Three Limited | Health & social care | 2022 |
| Tdmp Two Limited | Health & social care | 2020 |
| TDS Electrical Limited | Construction | 2012 |
| TDW Harley Holdings Limited | Financial services | 2021 |
| TDW Publishing Ltd | Information & communication | 2026 |
| TDZ Electrical Ltd | Construction | 2017 |
| TDZ Homes Ltd | Real estate | 2025 |
| TE Blackwell Engineering Limited | Professional & scientific | 2019 |
| Tea and Tinnies Games Limited | Manufacturing | 2025 |
| Teal Commercials Limited | Wholesale & retail | 2015 |
| Tealbluedragonfly Limited | Real estate | 2020 |
| Team Fitty App Limited | Other services | 2022 |
| Team Fitty Limited | Other services | 2022 |
| Teams Reconnected Limited | Professional & scientific | 2018 |
| Teamwatch Limited | Wholesale & retail | 2000 |
| Teather Property Investments Limited | Real estate | 2015 |
| Tech Bake Ltd | Information & communication | 2024 |
| Tech Futurae Limited | Wholesale & retail | 2020 |
| Technical Works Limited | Construction | 2008 |
| Technodyne International Limited | Professional & scientific | 1997 |
| Technology-Trend Limited | Information & communication | 2012 |
| Techo Air Limited | Information & communication | 2025 |
| Techo Info Ltd | Wholesale & retail | 2023 |
| Tehami Endocare Ltd | Health & social care | 2026 |
| TEK21 Limited | Information & communication | 2024 |
| Teleflor International Limited | Administrative & support | 1993 |
| Teleflorist Limited | Administrative & support | 1996 |
| Telegraph Hill Music Ltd | Education | 2025 |
| Teliho Limited | Extraterritorial | 2016 |
| Telling Creations Limited | Manufacturing | 2002 |
| Telmar CNC Ltd | Administrative & support | 1997 |
| Tembo Cleaning Services Limited | Administrative & support | 2023 |
| Test Valley (Insurances) Limited | Financial services | 1967 |
| Test Valley Venison Limited | Manufacturing | 2020 |
| Testwood Consulting Limited | Professional & scientific | 2017 |