| Torwood Investments-Livgreen Ltd | Other services | 2026 |
| Torybrook Court Management Company Limited | Households | 1987 |
| Toshiba Consumer Products (U.K.) Limited | Manufacturing | 1980 |
| Toskel Community Heritage and Culture CIC | Arts & recreation | 2025 |
| Total Build (SW) Ltd | Construction | 2025 |
| Total Defence Security Ltd | Administrative & support | 2018 |
| Total Electrical SW Ltd | Construction | 2017 |
| Total Repair Service Ltd | Construction | 2009 |
| Totally Emmeline Ltd | Wholesale & retail | 2022 |
| Totally Guttered Ltd | Administrative & support | 2021 |
| Totally Unhinged Productions Ltd | Arts & recreation | 2024 |
| Totalsports (UK) Ltd | Wholesale & retail | 2011 |
| Totem Timber Limited | Wholesale & retail | 1972 |
| Totem Timber Plymouth Limited | Wholesale & retail | 2010 |
| Totnes Classic Motorcycles Ltd | Wholesale & retail | 2014 |
| Totnes Market Ltd | Hospitality | 2026 |
| Toualeu & Co Ltd | Transport & logistics | 2016 |
| Tough Trading Limited | Construction | 2019 |
| Tower Cabs Limited | Transport & logistics | 2007 |
| Town Housing Limited | Real estate | 2013 |
| Towngain Residents Management Limited | Households | 1987 |
| Toze Hospitality Group Ltd | Hospitality | 2024 |
| Tozer Holdings Limited | Education | 2025 |
| TPD Interior Designs Limited | Professional & scientific | 2022 |
| TQR Plymouth Holdings Limited | Financial services | 2019 |
| TQR Plymouth Limited | Administrative & support | 2005 |
| TQR Properties Exeter Limited | Real estate | 2023 |
| TQR Properties Limited | Real estate | 2019 |
| TR8 Ltd | Real estate | 2011 |
| Trace Projects Limited | Arts & recreation | 2021 |
| Track Record Recruiting Ltd | Administrative & support | 2026 |
| Tracktrend Limited | Professional & scientific | 2002 |
| Trade Cookers Limited | Wholesale & retail | 2004 |
| Trade Innovate Ltd | Wholesale & retail | 2024 |
| Trade Security SW Ltd | Administrative & support | 2025 |
| Trademark Cars Plymouth Ltd | Wholesale & retail | 2025 |
| Tradepark Management Limited | Households | 1991 |
| TRADES4YOU Ltd | Construction | 2023 |
| Tradesman's Edge Ltd | Information & communication | 2026 |
| Tradetreasure Enterprises Limited | Wholesale & retail | 2024 |
| Trading Bargains Limited | Extraterritorial | 2011 |
| Trading Solution Partners Limited | Real estate | 2013 |
| Trafalgar Court Amenity Limited | Households | 2014 |
| Trafalgar SW Limited | Real estate | 2024 |
| Train 2 Gain Fitness (SW) Ltd | Arts & recreation | 2024 |
| Train to Gain SW Limited | Arts & recreation | 2023 |
| Train.Volt Limited | Wholesale & retail | 2023 |
| Trained by Swain Ltd | Education | 2026 |
| Trannings Automotive Specialists Limited | Wholesale & retail | 2014 |
| Tranquility Music Group Ltd | Information & communication | 2020 |
| Tranquility Yachts Ltd | Hospitality | 2022 |
| Trans Channel Ferries Limited | Extraterritorial | 1978 |
| Trans Euro Trail Community Interest Company | Administrative & support | 2018 |
| Trans Global Training Ltd | Education | 2019 |
| Transform MS CIC | Professional & scientific | 2019 |
| Transform My Health Limited | Health & social care | 2022 |
| Transforming Plymouth Together | Other services | 2015 |
| Transit Garage Limited | Wholesale & retail | 2002 |
| Transmaks Ltd | Administrative & support | 2016 |
| Transom Project Services Ltd | Administrative & support | 2024 |
| Transport and Lifting Services Ltd | Other services | 2016 |
| Transport Information Finance Limited | Information & communication | 2000 |
| Transport Operations Limited | Extraterritorial | 2011 |
| Transporter Forums Ltd | Other services | 2017 |
| Trattoria Capri Ltd | Hospitality | 2022 |
| Trauma Informed Plymouth Network Community Interest Company | Other services | 2021 |
| Trauma Therapy UK Ltd | Professional & scientific | 2023 |
| TRAVEL2HOME Limited | Hospitality | 2020 |
| Traynor Properties Limited | Real estate | 1975 |
| TRC (South West) Ltd | Construction | 2016 |
| Treats and Treasures Ltd | Wholesale & retail | 2021 |
| Tredhek Investments Limited | Real estate | 2018 |
| Tree-Work Ltd | Extraterritorial | 2002 |
| Treeby Developments Limited | Real estate | 2018 |
| Treegar Ltd | Wholesale & retail | 2003 |
| Treehouse Consultancy Ltd | Professional & scientific | 2012 |
| Treerunner Engineering Ltd | Professional & scientific | 2026 |
| Tregarland Limited | Health & social care | 2002 |
| Trei Mates Ltd | Hospitality | 2025 |
| Trellech Property Ltd | Households | 2022 |
| Trellis Properties Ltd | Hospitality | 2025 |
| Trelyn Offshore Ltd | Professional & scientific | 2024 |
| Trelys Hospitality Ltd | Hospitality | 2026 |
| Tremayne Ralph Ltd | Wholesale & retail | 2025 |
| Trenant House Limited | Health & social care | 2009 |
| Trenerg Ltd | Construction | 2013 |
| Trenethick Farming Limited | Financial services | 2025 |
| Trenouth Construction Limited | Construction | 2011 |
| Trerieve 567 Ltd | Construction | 2024 |
| Tresana Ltd | Health & social care | 2022 |
| Trevallett Dairy Limited | Manufacturing | 2025 |
| Trevana Cornwall Limited | Agriculture & fishing | 2026 |
| Trevaunance Holdings Limited | Financial services | 2022 |
| Trevenna Ltd | Hospitality | 2008 |
| Treverbyn Management Company (Plympton) Limited | Extraterritorial | 2006 |
| Trevi Women Ltd | Health & social care | 1999 |
| Trevilges Farm Limited | Agriculture & fishing | 2013 |
| Trevillion Property Services Ltd | Construction | 2025 |
| Trevor Burrows Photography Limited | Professional & scientific | 2000 |
| Trevor Denford Transport Ltd. | Transport & logistics | 2002 |