| TRI County Property Services Limited | Real estate | 2017 |
| TRI Green Cycle Limited | Manufacturing | 2024 |
| Trial Factor Ltd | Professional & scientific | 2014 |
| Trialight Ltd | Information & communication | 2026 |
| Trials Solutions Ltd | Professional & scientific | 2005 |
| Triangle Online Trading Ltd | Wholesale & retail | 2018 |
| Triangle Wave Ltd | Information & communication | 2024 |
| Tribunal Solutions Ltd | Professional & scientific | 2013 |
| Tribune London Ltd | Professional & scientific | 2025 |
| Tribus-D Ltd | Manufacturing | 2016 |
| Tricia & Paul Properties Ltd | Households | 2022 |
| Trickle Supplements Limited | Wholesale & retail | 2025 |
| Tricol Services Ltd | Manufacturing | 2020 |
| Tricolor Limited | Professional & scientific | 2010 |
| Tricumen Limited | Administrative & support | 2008 |
| Trident Energy Limited | Manufacturing | 2003 |
| Trident IOT UK Limited | Information & communication | 2026 |
| Trieres Engineering Ltd | Professional & scientific | 2022 |
| Trifan Flooring Limited | Construction | 2025 |
| Trifle Consulting Limited | Real estate | 2010 |
| Trigger's Broom Properties Ltd | Real estate | 2019 |
| Trijet Limited | Professional & scientific | 2011 |
| Trillion Listed Service Group Co., Limited | Extraterritorial | 2025 |
| Trilo (UK) Limited | Other services | 1994 |
| Trilo Hire Limited | Extraterritorial | 2008 |
| Trilogy Communications Holdings Limited | Information & communication | 1998 |
| Trilogy Writing & Consulting Limited | Professional & scientific | 2011 |
| Trim Classics Ltd | Other services | 2024 |
| Trimmer Composite Ltd | Manufacturing | 2025 |
| Trimounts Ltd | Wholesale & retail | 2025 |
| Trimtech Barbers Ltd | Other services | 2024 |
| Trimtech Therapeutics Limited | Professional & scientific | 2023 |
| Trinity Accounting & Consultancy Limited | Professional & scientific | 2019 |
| Trinity Biotech (UK) Limited | Health & social care | 2013 |
| Trinity Carestaff Solutions Limited | Health & social care | 2016 |
| Trinity Children’S Services Limited | Health & social care | 2026 |
| Trinity Dental Clinic Ltd | Health & social care | 2025 |
| Trinity Energy Ltd | Professional & scientific | 2019 |
| Trinity Engineering and Component Supplies Limited | Wholesale & retail | 2006 |
| Trinity Farm Fishery Ltd. | Administrative & support | 2019 |
| Trinity Farm Holiday Rentals Limited | Hospitality | 2019 |
| Trinity Gate Residents Limited | Households | 2007 |
| Trinity Greyhounds Limited | Arts & recreation | 2014 |
| Trinity Hall Farm Residents Society Limited | Professional & scientific | 1969 |
| Trinity Harper Cleaning Ltd | Administrative & support | 2016 |
| Trinity Harper Homes Limited | Financial services | 2024 |
| Trinity Ideas Limited | Information & communication | 2022 |
| Trinity Property Lettings (Cambridge) Limited | Real estate | 2022 |
| Trinity Repairs Limited | Construction | 2025 |
| Trinity Tree Solutions Ltd | Agriculture & fishing | 2020 |
| Trinity Way Management Company Limited | Real estate | 2016 |
| Trio Walden Limited | Hospitality | 2024 |
| Tripartite Capital Limited | Financial services | 2022 |
| Tripism Limited | Information & communication | 2014 |
| Triple a Tech Limited | Information & communication | 2025 |
| Triple E & E Limited | Administrative & support | 2022 |
| Triple Helical Peptides Ltd | Professional & scientific | 2023 |
| Triple L International Trade Ltd | Wholesale & retail | 2026 |
| Triple Line Technology Limited | Professional & scientific | 2016 |
| Tripos Ltd | Information & communication | 2026 |
| Triptrip Limited | Wholesale & retail | 2025 |
| Trishool Limited | Hospitality | 2023 |
| Trismik Ltd | Information & communication | 2025 |
| Tristar International Co., Ltd. | Extraterritorial | 2015 |
| Tristero Limited | Professional & scientific | 2001 |
| Triton Seed Drills Ltd | Agriculture & fishing | 2017 |
| Triumph Consultancy Services Limited | Professional & scientific | 2002 |
| Triumph Holdings Limited | Financial services | 2018 |
| Triumph Research Intelligence Limited | Information & communication | 2013 |
| Trocadero Holdings Ltd | Other services | 2020 |
| Trofor Vladimir Stefan Ltd | Manufacturing | 2024 |
| Trojan Homes (Cambridge) Limited | Construction | 2016 |
| Troka Advisory Limited | Professional & scientific | 2026 |
| Trombi Motors Ltd | Manufacturing | 2023 |
| Tropical Biology Association Limited | Education | 2006 |
| Trova Limited | Professional & scientific | 2009 |
| Trovian Ltd | Information & communication | 2026 |
| Troy Facilities Ltd | Administrative & support | 2020 |
| Troy Security Limited | Administrative & support | 2011 |
| TRR Property Limited | Other services | 2015 |
| Truce Holdings Limited | Information & communication | 2025 |
| Trucketts Hall Farm Boxted Limited | Agriculture & fishing | 1978 |
| Truckin Tasty Limited | Hospitality | 2025 |
| True Bloom Ltd | Wholesale & retail | 2022 |
| True Frontier Ltd | Hospitality | 2015 |
| True River Ltd | Real estate | 2024 |
| Trueblood Labs Ltd | Information & communication | 2026 |
| Truefootprint Ltd | Professional & scientific | 2018 |
| Truemed Ltd | Wholesale & retail | 2023 |
| Truemoment Ltd | Wholesale & retail | 2021 |
| Truewavesolutions Ltd | Wholesale & retail | 2025 |
| Truffle PIG Investments Ltd | Financial services | 2021 |
| Truhands Limited | Administrative & support | 2026 |
| Trumpington Educational Limited | Education | 2010 |
| Trumpington Enterprises Limited | Agriculture & fishing | 1986 |
| Trumpington Farm Company, Limited | Agriculture & fishing | 1957 |
| Trumpington Fine Books Limited | Wholesale & retail | 2008 |
| Trumpington Gallery (Conservation) Limited | Other services | 1985 |
| Trumpington Group Limited | Construction | 2025 |
| Trumpington Investments Limited | Real estate | 1994 |