| Diamond International Overseas Ltd | Financial services | 2008 |
| Digimonk Ltd | Information & communication | 2020 |
| Digital Design NE Ltd | Professional & scientific | 2024 |
| Digital First Solutions Ltd | Information & communication | 2015 |
| Digital Tickle Ltd | Information & communication | 2019 |
| Dimensional Wealth Group Limited | Professional & scientific | 2024 |
| Dingo Recruitment Ltd | Administrative & support | 2017 |
| Dinsdale Plumbing & Heating Limited | Construction | 2014 |
| Direct Medical Transport Limited | Transport & logistics | 2013 |
| Direct Wood Flooring Limited | Wholesale & retail | 2013 |
| Diversify Property Solutions Ltd | Real estate | 2016 |
| DJ Merryweather's Limited | Agriculture & fishing | 2021 |
| Djam Kitchen Limited | Hospitality | 2021 |
| DM Entertainment Services Ltd | Administrative & support | 2025 |
| DM Plumbing & GAS Services Ltd | Construction | 2015 |
| DNB Management Services Ltd | Professional & scientific | 2025 |
| DO Business Like a Woman Ltd | Administrative & support | 2021 |
| DOC Eyes Ltd | Real estate | 2022 |
| Dog's Day Home Ltd | Other services | 2023 |
| Dolmay Construction Limited | Construction | 2001 |
| Doughty Plant Ltd | Administrative & support | 2013 |
| DPS (North East) Limited | Manufacturing | 2020 |
| DR Julie Oliver Limited | Health & social care | 2013 |
| DR Redman Aesthetics Ltd | Health & social care | 2023 |
| Draco Cleaning Services Limited | Administrative & support | 2014 |
| Dragonville Projects Limited | Wholesale & retail | 2020 |
| Drama in the Dale CIC | Arts & recreation | 2015 |
| Dream Decking Ltd | Wholesale & retail | 2024 |
| Dreams Come True Events Ltd. | Other services | 2021 |
| Drew Sams Brickwork & Stonework Contractors Limited | Construction | 2022 |
| DRIVE2BUSINESS Limited | Professional & scientific | 2014 |
| DT and RS Gardening Ltd | Administrative & support | 2024 |
| DT Collectibles Ltd | Wholesale & retail | 2026 |
| DT Groundworks Limited | Construction | 2014 |
| Dublin Show Productions Ltd | Arts & recreation | 2025 |
| DUN Holm Scaffolding Ltd | Construction | 2025 |
| Durham City Controls Ltd. | Construction | 2013 |
| Durham Climbing Cafe Ltd | Hospitality | 2023 |
| Durham Climbing Centre Limited | Arts & recreation | 2011 |
| Durham Climbing Kids Ltd | Arts & recreation | 2023 |
| Durham Climbing Property Ltd | Real estate | 2023 |
| Durham Dales Health | Professional & scientific | 2008 |
| Durham EAR Care Ltd | Health & social care | 2026 |
| Durham Estates (NE) Limited | Real estate | 2025 |
| Durham Hens Limited | Agriculture & fishing | 2011 |
| Durham Homes Limited | Real estate | 2016 |
| Durham Housing Solutions Ltd | Real estate | 2024 |
| Durham Parcel Delivery Ltd | Transport & logistics | 2018 |
| Durham Pipelines Limited | Construction | 2024 |
| Durham Plumbing Limited | Construction | 2005 |
| Durham Private Doctors Limited | Health & social care | 2017 |
| Durham Web Design Ltd | Professional & scientific | 2024 |
| Dursand Ltd | Mining & quarrying | 2015 |
| DW Floor Screed Ltd | Construction | 2019 |
| Dynamic Commercial Decorators Limited | Construction | 2016 |
| Dynamic Engineering (NE) Limited | Construction | 2025 |
| Dynamic Scaffold Solutions Ltd | Construction | 2025 |
| E & I Offshore Services Limited | Professional & scientific | 2014 |
| E & T Bradley Property Developments Limited | Households | 2025 |
| E Co Accommodation Ltd | Real estate | 2023 |
| E Co Accommodation Management Ltd | Real estate | 2024 |
| E Co Properties and Developments Ltd | Real estate | 2023 |
| E I'Anson Limited | Construction | 2009 |
| E-Commercials Limited | Information & communication | 2005 |
| E-Quality Systems Limited | Information & communication | 2009 |
| Easby Property Management Limited | Real estate | 2009 |
| East Parade Management Company (Bishop Auckland) Limited | Real estate | 2011 |
| East Parade Management Company Limited | Hospitality | 2002 |
| Ebac Industrial Products Limited | Manufacturing | 2003 |
| Ebdon's Enterprise Ltd | Other services | 2024 |
| ECB Cigarettes Ltd | Wholesale & retail | 2017 |
| Eclairer Limited | Extraterritorial | 2014 |
| Eco International Ltd | Manufacturing | 2025 |
| Eco PL Ltd | Wholesale & retail | 2006 |
| ECS International Limited | Information & communication | 2018 |
| ECT Electrical Limited | Construction | 2016 |
| Eden BUS Services Limited | Transport & logistics | 2015 |
| Eden Energy Installations Limited | Construction | 2025 |
| Edways Estates Limited | Real estate | 2020 |
| EEP Properties Ltd | Real estate | 2025 |
| EFT Architectural Fabrications Limited | Manufacturing | 2011 |
| Eistop Limited | Real estate | 2005 |
| EL Fifty Limited | Education | 2019 |
| Elave Ltd | Wholesale & retail | 2025 |
| Elbon Enterprises (North East) Limited | Financial services | 2019 |
| Eldon Tyres Limited | Wholesale & retail | 2006 |
| Eldrett Finch Limited | Manufacturing | 2006 |
| Electrica Services Ltd | Construction | 2021 |
| Electrix International Holdings Limited | Financial services | 2019 |
| Elegant Scents Ltd | Wholesale & retail | 2025 |
| Elevent Alliance Capital Limited | Financial services | 2023 |
| Elgy Draughting Limited | Professional & scientific | 2011 |
| ELI Press Ltd. | Information & communication | 2000 |
| Elif 5623 Ltd | Hospitality | 2023 |
| Elite Brickwork Contractors Ltd | Construction | 2021 |
| Elite Tactical Force Limited | Administrative & support | 2020 |
| Ellen Holcombe Ltd | Professional & scientific | 2021 |
| ELR Site Engineering Limited | Administrative & support | 2013 |
| Elsakaalya Ltd | Hospitality | 2025 |
| EMB Retail Ltd | Wholesale & retail | 2026 |