| Tourismo Limited | Administrative & support | 2020 |
| Tournament Chukkas Limited | Arts & recreation | 2005 |
| Tovell Builders Ltd. | Construction | 2002 |
| Towards Independence Occupational Therapy Consultancy Ltd | Health & social care | 2026 |
| Tower Worldwide (Basildon) Limited | Transport & logistics | 2010 |
| Town & Rural Recruitment Limited | Extraterritorial | 2024 |
| Town Convenience Ltd | Wholesale & retail | 2022 |
| Town Newsagents Ltd | Wholesale & retail | 2022 |
| Town Pastors (Ipswich) | Other services | 2008 |
| Toy Bargains UK Limited | Wholesale & retail | 2026 |
| Toybox (Gatacre Road) Pre-School Group Limited | Education | 2010 |
| TP (East) Ltd | Real estate | 2024 |
| TP Chipper Limited | Agriculture & fishing | 2026 |
| TP Performance Management Ltd | Other services | 2026 |
| TPD Interiors Limited | Manufacturing | 2014 |
| TPH Retail Ltd | Wholesale & retail | 2025 |
| TPI Consultancy Limited | Professional & scientific | 2022 |
| TR Shipping Limited | Transport & logistics | 2021 |
| Tracey James UK Ltd. | Administrative & support | 2003 |
| Tracey Jarrad Hairdressing Ltd | Other services | 2014 |
| Tracklancers Ltd | Wholesale & retail | 2025 |
| Tractor Tyres Direct Ltd | Administrative & support | 2008 |
| Trade Supply Windows (Ipswich) Limited | Administrative & support | 2002 |
| Trade Wealth Limited | Administrative & support | 2024 |
| Trade Windows Suffolk Ltd | Construction | 2022 |
| Tradepinnacle Group Ltd | Wholesale & retail | 2024 |
| Tradewind Voyages UK Ltd | Administrative & support | 2020 |
| Trading Cards and Collectables Ltd | Wholesale & retail | 2025 |
| Traditional Brickwork Ltd | Construction | 2022 |
| Tradoria Limited | Wholesale & retail | 2025 |
| Trafalgar Close Residents' Company Limited | Households | 2017 |
| Trafalgar Communications Ltd | Information & communication | 2018 |
| Trafalgar Group Trading Ltd | Wholesale & retail | 2008 |
| Trafalgar Retail Ltd. | Wholesale & retail | 2009 |
| Trafalgar Scuba Diving Ltd | Wholesale & retail | 2021 |
| Trafford Stud | | 1997 |
| Trailer Control Limited | Extraterritorial | 1985 |
| Trailwave Ltd | Information & communication | 2025 |
| Train AI Media Ltd | Information & communication | 2026 |
| Training for Construction Limited | Education | 2014 |
| Training for Life (South East) Limited | Education | 2020 |
| Training Vehicle Solutions Limited | Administrative & support | 2020 |
| Tranquility Beauty Rooms Ltd. | Other services | 2005 |
| Trans Logistics 2023 Ltd | Transport & logistics | 2023 |
| Transactive Systems Ltd | Information & communication | 2017 |
| Transccalin Ltd | Transport & logistics | 2023 |
| Transdacian Ltd | Wholesale & retail | 2020 |
| Transglobal Serv UK Ltd | Transport & logistics | 2025 |
| Transhroma Ltd | Wholesale & retail | 2021 |
| Transio Global Ltd | Wholesale & retail | 2025 |
| Transition Films Limited | Professional & scientific | 2019 |
| Transition Finance (Lavenham) Limited | Financial services | 2015 |
| Transkriss Haulage Ltd | Transport & logistics | 2021 |
| Translation & Interpreting Provider Ltd | Professional & scientific | 2012 |
| Transport 212 Limited | Transport & logistics | 2024 |
| Transportation HM Limited | Transport & logistics | 2013 |
| Trautman SAN Kapital Ltd | Construction | 2019 |
| Travel Stop Limited | Administrative & support | 2017 |
| Traydon Ltd | Wholesale & retail | 2025 |
| TRE Maxima Ltd | Wholesale & retail | 2022 |
| Treasure Trails Suffolk Ltd | Wholesale & retail | 2009 |
| Treat Your Lawn Essex Limited | Administrative & support | 2014 |
| Treat Your Lawn Ltd | Administrative & support | 2002 |
| Tree Store Ltd | Wholesale & retail | 2026 |
| Tree Tech Group Ltd | Financial services | 2023 |
| Tree Tech Suffolk Limited | Agriculture & fishing | 2019 |
| Treeincarnated Limited | Manufacturing | 2009 |
| Treetops Management Grundisburgh Limited | Households | 2020 |
| Treewright Ltd | Construction | 2024 |
| Trellory Systems Ltd | Information & communication | 2026 |
| Trench Monkeys Airsoft Ltd | Wholesale & retail | 2025 |
| Trenchborncollective Ltd | Wholesale & retail | 2026 |
| Trend Home Improvements Ltd | Construction | 2022 |
| Trendy F&B Limited | Hospitality | 2026 |
| Trendycraft Ltd | Professional & scientific | 2025 |
| Trenter Bacon Limited | Professional & scientific | 2008 |
| Trevor Foreman Solutions Limited | Professional & scientific | 2010 |
| Trevor Gilbert & Associates Limited | Professional & scientific | 1996 |
| Trevor Sadler Ltd | Construction | 2011 |
| Trezak Limited | Information & communication | 2005 |
| Triames Insight Ltd | Professional & scientific | 2019 |
| Triangle (Ipswich) Motor Cycle Club Limited | Arts & recreation | 1981 |
| Triangle Living Water Limited | Wholesale & retail | 1997 |
| Triarch Group Ltd | Construction | 2024 |
| Tribaltravel Ltd | Administrative & support | 2023 |
| Tricky Bits Ltd | Information & communication | 2017 |
| Trifarm Ltd | Arts & recreation | 2013 |
| Trifocord Ltd | Real estate | 2025 |
| Trimley Ltd | Manufacturing | 2025 |
| Trinity Autos Ipswich Ltd | Wholesale & retail | 2019 |
| Trinity Fuels & Marine Limited | Wholesale & retail | 2005 |
| Trinity Health Limited | Health & social care | 2020 |
| Trinity HR Ltd | Information & communication | 2016 |
| Trinity Park Events Limited | Real estate | 1997 |
| Trinity Rise (Ormesby ST Margaret) Management Company Limited | Households | 2025 |
| Trinity Trade Group Limited | Wholesale & retail | 2018 |
| Trinity Tuition Group Ltd | Education | 2018 |
| Trinity Tyres (Felixstowe) Limited | Wholesale & retail | 2002 |
| Trinity Veterinary Limited | Professional & scientific | 2013 |
| TRINITY1CARE Ltd | Health & social care | 2019 |