| T Monaghan Ltd | Real estate | 2026 |
| T S Gibson Ltd | Agriculture & fishing | 2024 |
| T Stevens Ltd | Wholesale & retail | 2009 |
| T Studholme Electrical Limited | Construction | 2004 |
| T W Bendle Limited | Transport & logistics | 2002 |
| T W Pluckrose Limited | Real estate | 2024 |
| T&D Homes Ltd | Real estate | 2024 |
| T&H Signature Homes Ltd | Real estate | 2026 |
| T&S Air Conditioning Limited | Construction | 2009 |
| T. E. Gallimore and Sons Limited | Construction | 2002 |
| T.G. O'Fee Limited | Agriculture & fishing | 1977 |
| T.L. Armstrong Limited | Administrative & support | 2006 |
| T.L.C. Heating Services Ltd | Administrative & support | 2016 |
| T.W. Bell Auto Salvage Limited | Wholesale & retail | 2006 |
| Tactical Armour Group Ltd | Manufacturing | 2019 |
| Taekwondo Schools UK Ltd | Arts & recreation | 2008 |
| TAG Tax Limited | Professional & scientific | 2016 |
| Tait Engineering (Carlisle) Limited | Professional & scientific | 2014 |
| TAL Logistics Limited | Transport & logistics | 2017 |
| Talkin Gardens Management Company Limited | Households | 1999 |
| TAN Central Limited | Other services | 2025 |
| Tanik Brothers Ltd | Hospitality | 2019 |
| TAP & Take Ltd | Wholesale & retail | 2025 |
| TAP a Taxi Ltd | Transport & logistics | 2023 |
| Tapp Media Limited | Professional & scientific | 2024 |
| Tarn Saunas Ltd | Health & social care | 2025 |
| Tasker & Shaw Menswear Limited | Wholesale & retail | 2024 |
| Taskscape Associates Limited | Information & communication | 2006 |
| Taste Beverages Limited | Wholesale & retail | 2009 |
| Tasty Foods Station Ltd | Hospitality | 2025 |
| Tatties an' That Ltd | Hospitality | 2023 |
| Tattoo Studio 49 Ltd | Arts & recreation | 2023 |
| Tavistock Motor Company Limited | Wholesale & retail | 2010 |
| Taylor ME Cumbria Ltd | Construction | 2009 |
| Tayloreliteclosing Limited | Administrative & support | 2025 |
| Taylors Tax Practice Limited | Professional & scientific | 2003 |
| TBT Properties Ltd | Real estate | 2021 |
| TBW Cleaning & Maintenance Ltd | Administrative & support | 2023 |
| TBW Renovations & Maintenance Ltd | Other services | 2019 |
| TC Conversions Limited | Manufacturing | 2014 |
| TC Design Services Ltd | Professional & scientific | 2020 |
| TC Power Ltd | Wholesale & retail | 2018 |
| TC Scaffolding (Carlisle) Holdings Limited | Construction | 2015 |
| TC Scaffolding (Carlisle) Limited | Construction | 2015 |
| TCH Farms Limited | Agriculture & fishing | 2012 |
| Tcha Engineering Ltd | Professional & scientific | 2024 |
| TCR (Carlisle) Ltd | Professional & scientific | 2024 |
| TCS Cumbria Limited | Manufacturing | 2025 |
| TDB (Cumbria) Ltd | Construction | 2011 |
| TDB Builders Limited | Construction | 2025 |
| TDP Leisure Limited | Hospitality | 2017 |
| Tdproperty Ltd | Real estate | 2020 |
| Teacheco Ltd | Education | 2012 |
| Teal Consultants Limited | Professional & scientific | 2015 |
| Team Autism CIC | Health & social care | 2021 |
| Team Oliver Racing Limited | Arts & recreation | 2011 |
| Team Rbwm Ltd | Financial services | 2016 |
| Team Shackleton Limited | Professional & scientific | 2017 |
| Teasdales Confectionary Ltd | Manufacturing | 2003 |
| Tech 4 Office Equipment Limited | Administrative & support | 2009 |
| Tech 4 Office Solutions Limited | Professional & scientific | 2005 |
| Tech Recycle Limited | Information & communication | 2010 |
| Technical Engineering Services (UK) Limited | Professional & scientific | 2000 |
| Techno Techno Techno Ltd | Information & communication | 2022 |
| Tecnopharma UK Limited | Professional & scientific | 2020 |
| Tefl Avenues Limited | Education | 2025 |
| Telford Management Company Limited | Real estate | 2007 |
| TEN & Fower Ltd | Wholesale & retail | 2025 |
| Tenletter Ltd | Professional & scientific | 2023 |
| Tenmanor Limited | Administrative & support | 1985 |
| Tenterfield Management Company Limited | Households | 2017 |
| Tenureshare Property Management Limited | Households | 1995 |
| Terrainworxs Ltd | Administrative & support | 2021 |
| Terris Electrical & Co. Limited | Construction | 1992 |
| Testronix Ltd | Construction | 2024 |
| Testudo Security Ltd | Administrative & support | 2022 |
| Tethera Veterinary Services Limited | Professional & scientific | 2011 |
| TGF Rule and Sons Ltd | Construction | 2021 |
| TGL Entertainment Ltd | Information & communication | 2025 |
| TGW Utilities Ltd | Construction | 2024 |
| Thackwood Farming Company | Administrative & support | 2010 |
| Thackwood Farms Limited | Agriculture & fishing | 2006 |
| Thai Food Ingredients Limited | Hospitality | 2019 |
| Thai Market Limited | Wholesale & retail | 2015 |
| Thai Restaurant Carlisle Limited | Hospitality | 2024 |
| Thai Thai Carlisle Limited | Hospitality | 2023 |
| Thank Abba for the Music Limited | Extraterritorial | 2014 |
| That Bookkeeping GUY Limited | Professional & scientific | 2016 |
| Thatcham Ltd | Financial services | 2024 |
| THE 37 Lonsdale Street Management Company Limited | Administrative & support | 2011 |
| THE AD Guys Ltd | Professional & scientific | 2024 |
| THE Aesthetics Club Carlisle Ltd | Other services | 2025 |
| THE Aesthetics Nurse Ltd | Other services | 2026 |
| THE Association of Private Pet Cemeteries & Crematoriums Limited | Other services | 1993 |
| THE Audio Collective Limited | Arts & recreation | 2008 |
| THE Avenue (Stainburn) Management Limited | Households | 2015 |
| THE Bare Necessities Pet Care Services Limited | Other services | 2021 |
| THE Base Express (Cumbria) Ltd | Hospitality | 2017 |
| THE Beauty Lounge by Rachel Thomson Limited | Other services | 2016 |
| THE BED Shop Carlisle.Com Limited | Wholesale & retail | 2008 |