| Titan Digital Exchange Limited | Professional & scientific | 2021 |
| Titan Group UK Holdings Ltd | Construction | 2018 |
| Titancumbria Ltd | Administrative & support | 2026 |
| Titanic Productions Ltd | Arts & recreation | 2026 |
| Tithe Gardens (Poulton) Management Company Limited | Real estate | 2021 |
| TJL Holdings Ltd | Professional & scientific | 2015 |
| TK Bars Ltd | Hospitality | 2026 |
| TKJ Engineering Limited | Administrative & support | 2017 |
| TKL Carlisle Ltd | Wholesale & retail | 2025 |
| TKL Painting & Roofing Limited | Construction | 2022 |
| TLC Deliveries UK Ltd | Transport & logistics | 2018 |
| Tlec Holdings Ltd | Wholesale & retail | 2026 |
| Tlowes Logistics Ltd | Transport & logistics | 2025 |
| TN Flagship Investments Ltd | Real estate | 2024 |
| TO the Nines Limited | Hospitality | 2014 |
| Toby Smith Design Services Ltd | Professional & scientific | 2014 |
| Todd's Bathrooms Limited | Construction | 2011 |
| Tokar 63 Limited | Professional & scientific | 2014 |
| TOM Benson Consulting Limited | Professional & scientific | 2015 |
| TOM Brown Construction Limited | Construction | 2002 |
| TOM Farrell Enterprises Limited | Arts & recreation | 2014 |
| Tom's Kitchen Cumbria Ltd | Hospitality | 2020 |
| Tone and TAN Limited | Wholesale & retail | 2002 |
| Tongue Gill Enterprises Limited | Energy | 2012 |
| Tony Bar Ltd | Manufacturing | 2014 |
| Tony K Trans Ltd | Transport & logistics | 2019 |
| Tony Little Safety Critical Services Limited | Professional & scientific | 2017 |
| Toolfix Direct Limited | Extraterritorial | 2001 |
| Toolking Limited | Wholesale & retail | 2016 |
| Toosie Bawden Physiotherapy Limited | Health & social care | 2008 |
| Top CUT Style Ltd | Other services | 2025 |
| Top Dog Sitters Limited | Other services | 2012 |
| Top Marks Driving School (Carlisle) Ltd | Education | 2020 |
| Top Notch Contractors Limited | Manufacturing | 2000 |
| Top Source Ltd | Wholesale & retail | 2025 |
| Top Spot M&K Properties Ltd | Real estate | 2019 |
| Top Trowel Developments Ltd | Construction | 2026 |
| Topcatz Ltd | Wholesale & retail | 2025 |
| Topmerit Limited | Professional & scientific | 2006 |
| Topweigh Ltd | Manufacturing | 2011 |
| TOR Developments Limited | Construction | 2003 |
| Total Engineering Developments Limited | Manufacturing | 2017 |
| Total Enigma Ltd | Arts & recreation | 2018 |
| Total Power Installations Ltd | Construction | 2013 |
| Total Print & Marketing Solutions Ltd | Manufacturing | 2019 |
| Touchstone Nuclear Limited | Administrative & support | 2011 |
| Town & Country Developments (Carlisle) Limited | Construction | 2007 |
| Town & Country Estate Agents Limited | Administrative & support | 1989 |
| Town & Country Maintenance (Carlisle) Limited | Construction | 2021 |
| Town & Country Roofing (Carlisle) Limited | Construction | 2009 |
| Townfoot | Agriculture & fishing | 2007 |
| Townfoot Garage Limited | Wholesale & retail | 2002 |
| Townfoot House Management Company Limited | Real estate | 1994 |
| Townfoot Valeting Limited | Other services | 2021 |
| Toys N Tech Ltd | Wholesale & retail | 2015 |
| Trackintelligent Limited | Information & communication | 2025 |
| Tractors Limited | Extraterritorial | 2003 |
| Trade Cars Carlisle Limited | Wholesale & retail | 2022 |
| Trade Colour Printing Limited | Manufacturing | 2015 |
| Trade Supplies U.K Ltd | Wholesale & retail | 2023 |
| Trade World (WG) Limited | Manufacturing | 1999 |
| Tradeforus Forestry Limited | Extraterritorial | 2021 |
| Trailbrakes Limited | Administrative & support | 2017 |
| Train Learn Go Northwest/East Ltd | Arts & recreation | 2016 |
| Train Safe Provider Ltd | Extraterritorial | 2013 |
| Trait Groundwork Ltd | Construction | 2020 |
| Transforming Care Services Ltd | Administrative & support | 2017 |
| Transport Properties Limited | Real estate | 2021 |
| Transportation Ltd | Manufacturing | 2025 |
| Transum Limited | Professional & scientific | 2013 |
| Trashbat | Financial services | 2022 |
| Travel and Teach Limited | Administrative & support | 2019 |
| Traveline Cumbria Limited | Transport & logistics | 2001 |
| TRB Electrical Services Ltd | Other services | 2016 |
| Tree Seed Online Ltd | Agriculture & fishing | 2012 |
| Treewise Solutions Limited | Agriculture & fishing | 2010 |
| Tres Marias Limited | Wholesale & retail | 2020 |
| Trevor Mcvittie Limited | Construction | 2008 |
| Tribal Warriors Network Ltd | Arts & recreation | 2025 |
| Triggerdown Limited | Other services | 2010 |
| Trinhof Limited | Information & communication | 2006 |
| Trinity School (Carlisle) Limited | Education | 1992 |
| Trinity School, a Church of England Academy | Education | 2011 |
| Triple Stone Properties Limited | Real estate | 2017 |
| Trotter & Little Limited | Manufacturing | 2024 |
| Trse Limited | Professional & scientific | 2025 |
| Truck Driver Rental Limited | Transport & logistics | 2016 |
| Truckapart Limited | Wholesale & retail | 2009 |
| True Media Group Limited | Information & communication | 2024 |
| True North 54 Limited | Information & communication | 2026 |
| True North Research & Policy Limited | Professional & scientific | 2024 |
| True North Safety Solutions Ltd | Professional & scientific | 2019 |
| True Turf Garden and Sports Ltd | Administrative & support | 2018 |
| Trust Dispute Resolution Limited | Professional & scientific | 2007 |
| Trustkeys Ltd | Administrative & support | 2018 |
| Tryscaffolding Limited | Construction | 1978 |
| Tt&Af Logistics Ltd | Transport & logistics | 2022 |
| TTJ Auto Assistance Limited | Transport & logistics | 2021 |
| Tudor Court (Penrith) Management Company Limited | Households | 2007 |
| Tullie House Museum and Art Gallery Trust | Arts & recreation | 2011 |