| THE Engineers Arms (Leiston) Limited | Hospitality | 2014 |
| THE Hotel Folk Limited | Hospitality | 1995 |
| THE Inn & House Company Ltd | Real estate | 2025 |
| THE KAN DO Kidd Ltd | Wholesale & retail | 2025 |
| THE Krafty Braumeister Ltd | Manufacturing | 2016 |
| THE SAM Buxton Sunflower Healing Trust | Health & social care | 2006 |
| Theatre IF Ltd | Arts & recreation | 2021 |
| Theberton and Eastbridge Action Group on Sizewell Ltd | Other services | 2019 |
| Thorpeness Country Club Management Company Limited | Households | 1998 |
| Three Corns Limited | Information & communication | 2016 |
| Tibbenham Construction Ltd | Construction | 2024 |
| Tirah Guest House Limited | Hospitality | 2015 |
| Together Against Sizewell C Ltd | Other services | 2022 |
| TOM Haste Farm Machinery Ltd | Wholesale & retail | 2023 |
| Tudor Black Coachworks Ltd | Manufacturing | 2022 |
| Tulsy Collection Ltd | Wholesale & retail | 2025 |
| Turnpike Farm Ltd | Information & communication | 2013 |
| Victoria Landscaping Services Ltd | Construction | 2023 |
| Victory Car Sales Limited | Wholesale & retail | 2003 |
| Victory Leasing Limited | Administrative & support | 2018 |
| Viper Automotive Limited | Wholesale & retail | 2025 |
| Ward Farming Limited | Agriculture & fishing | 2007 |
| West Surfacing Ltd | Professional & scientific | 2024 |
| White and Partners Limited | Agriculture & fishing | 2006 |
| Willow & Jack Ltd | Administrative & support | 2022 |
| Winterbrook Ingredients Limited | Manufacturing | 2019 |
| WKS Maintenance Ltd | Construction | 2018 |
| World Organization for Fitness and Wellness Ltd | Education | 2020 |
| Xerota Limited | Wholesale & retail | 2019 |
| Zeto Enterprises Ltd | Construction | 2023 |