| Topspin Southampton Ltd | Arts & recreation | 2024 |
| Tora Systems Limited | Wholesale & retail | 2025 |
| Torchjam Limited | Financial services | 2024 |
| Torix Ltd | Construction | 2018 |
| Tornado Limited | Information & communication | 2002 |
| Toseland Design Services Ltd | Information & communication | 2019 |
| Total Archive Group Limited | Wholesale & retail | 2026 |
| Total Array Ltd | Wholesale & retail | 2019 |
| Total Classics Ltd | Wholesale & retail | 2021 |
| Total Comms 123 Limited | Information & communication | 2021 |
| Total Communications & Networking Ltd | Information & communication | 2017 |
| Total Football 24 7 Limited | Wholesale & retail | 2006 |
| Total GAS (Hampshire) Limited | Construction | 2012 |
| Total Industrial Roofing Limited | Manufacturing | 2010 |
| Total Jetting Solutions Limited | Manufacturing | 2016 |
| Total Maintainability Ltd | Extraterritorial | 2023 |
| Total Party Ltd | Wholesale & retail | 2016 |
| Total Projects (Southern) Limited | Construction | 2022 |
| Total Properties (South) Ltd | Real estate | 2024 |
| Total Property Group Ltd | Real estate | 2024 |
| Total Props Ltd | Arts & recreation | 2017 |
| Total Refrigeration Services Ltd | Professional & scientific | 2020 |
| Total Resilience Limited | Administrative & support | 2008 |
| Total Solutions (Europe) Ltd | Other services | 1998 |
| Total Sports Conditioning Ltd | Education | 2020 |
| Total Utilities Group Limited | Energy | 2017 |
| Total Wardrobe Care Limited | Administrative & support | 2010 |
| Total Wardrobe Storage Limited | Wholesale & retail | 2011 |
| Total Water Compliance Ltd | Water & waste | 2016 |
| Totalcare Hampshire Limited | Health & social care | 2012 |
| Totton & Eling Tennis Centre Limited | Arts & recreation | 2004 |
| Totton & Hythe Couriers Limited | Transport & logistics | 2021 |
| Totton Charcoal Ltd | Hospitality | 2020 |
| Totton Chicken Ltd | Hospitality | 2020 |
| Totton Pizza & Chicken Ltd | Hospitality | 2023 |
| Totton Primary Care Network Ltd | Health & social care | 2026 |
| Totton Properties Limited | Real estate | 2015 |
| Totton Sports Limited | Other services | 2018 |
| Totton Timber Co.Limited | Wholesale & retail | 1957 |
| Touch Network CIC | Health & social care | 2016 |
| Touchdown Navigation Solutions Limited | Information & communication | 2024 |
| Touchnetix Limited | Manufacturing | 2010 |
| Touchstone Renard International Limited | Extraterritorial | 2014 |
| Touzel Properties Ltd | Real estate | 2019 |
| Towan Place RTM Company Ltd | Households | 2021 |
| Tower Farm Garden Holiday Lets Limited | Real estate | 2017 |
| Towerview (Sandhurst) Limited | Construction | 2017 |
| Town & Country Property Auctions Dorset & Hampshire Ltd | Real estate | 2018 |
| Town and Country Kitchens and Bathrooms Ltd | Wholesale & retail | 2019 |
| Townhill Farm Limited | Households | 2005 |
| Townhill Way District Centre (Communal Services) Management Co. Limited | Real estate | 1993 |
| Townhouse Stratford Ltd | Hospitality | 2020 |
| Townsend-Brown Capital Ltd | Real estate | 2017 |
| Townsley Rail Ltd | Professional & scientific | 2016 |
| Towser Associates Limited | Real estate | 2013 |
| Towy Garage Limited | Wholesale & retail | 1945 |
| Towzon Recovery Limited | Transport & logistics | 2025 |
| Toy Monsterz Ltd | Wholesale & retail | 2019 |
| TP Composites Ltd | Manufacturing | 2022 |
| TPAY365 Ltd | Information & communication | 2026 |
| TPC Construction Specialists Ltd | Administrative & support | 2020 |
| Tpcmncube Ltd | Health & social care | 2020 |
| TPI Hub Ltd | Wholesale & retail | 2015 |
| TPM Building & Property Maintenance Limited | Construction | 2014 |
| TPT Roofing & Paving Ltd | Construction | 2026 |
| TR CAD Limited | Professional & scientific | 2015 |
| TR Connect Limited | Wholesale & retail | 2021 |
| TR Southampton Ltd Limited | Extraterritorial | 2023 |
| TR4M Limited | Administrative & support | 2013 |
| Tracie's Latin Club Ltd | Real estate | 2007 |
| Track Party Ltd. | Construction | 2014 |
| Trackback Limited | Extraterritorial | 2019 |
| Tracker Marine Limited | Manufacturing | 2004 |
| Trackfleet Ltd | Manufacturing | 2026 |
| Tracy’S Treats Ltd | Wholesale & retail | 2026 |
| Trad-Itional Beauty Ltd | Other services | 2021 |
| Trade Base Direct Limited | Wholesale & retail | 2014 |
| Trade House Media Limited | Professional & scientific | 2016 |
| Trade Hub Pro Ltd | Wholesale & retail | 2025 |
| Trade KOI Ltd | Wholesale & retail | 2018 |
| Trade Vehicles Limited | Wholesale & retail | 2025 |
| Tradecall Limited | Information & communication | 2025 |
| Tradeforq Limited | Wholesale & retail | 2026 |
| Trademark Car Bodyshop and Spray Centre Ltd | Wholesale & retail | 2023 |
| Trademark Improvements Ltd | Construction | 2003 |
| Trademarkroom Limited | Professional & scientific | 2007 |
| Traders Direct Limited | Extraterritorial | 2003 |
| Trades People Local Ltd | Construction | 2023 |
| Trades Pro Software Ltd | Information & communication | 2022 |
| Tradewind Espresso Ltd | Hospitality | 2015 |
| Tradon Limited | Professional & scientific | 2019 |
| Trafalgar Consulting Ltd | Information & communication | 2004 |
| Trafalgar Court (Cobham) Management Company Limited | Households | 2004 |
| Trafalgar Court Property Management Company Limited | Households | 1993 |
| Trafalgar Shipyard Limited | Manufacturing | 2018 |
| Trafalgar Transformations Limited | Real estate | 2017 |
| Trafalgar Wharf Limited | Administrative & support | 2008 |
| Trafalgar Workspaces Ltd | Real estate | 2018 |
| Traffic Control 123 Limited | Professional & scientific | 2014 |
| Traian Petrencu Spedition Ltd | Administrative & support | 2015 |