| Express Commercials North East Limited | Wholesale & retail | 2014 |
| Express Hand Car Wash Durham Ltd | Other services | 2018 |
| Express Hand Valeting Durham Ltd | Administrative & support | 2022 |
| Express Rail Services Limited | Professional & scientific | 2018 |
| Express Traffic Management Limited | Construction | 2014 |
| Ey-Ze Global Ltd | Wholesale & retail | 2025 |
| F a M Building Services Limited | Construction | 2026 |
| F. Soudani Services & Investments Limited | Hospitality | 2025 |
| F2W Ltd | Construction | 2023 |
| FAB Beauty Ltd | Wholesale & retail | 2021 |
| Fabb Gear Limited | Wholesale & retail | 2004 |
| Fabi Burnett Limited | Professional & scientific | 2023 |
| Fabmill Engineering Limited | Manufacturing | 2019 |
| Fabs Cleaning Limited | Administrative & support | 2025 |
| Factory Fodder CIC | Other services | 2026 |
| Faerch Durham Limited | Manufacturing | 2011 |
| FAI Sun Limited | Hospitality | 2022 |
| Fair Play UK Limited | Real estate | 2008 |
| Fairway Brands Ltd | Wholesale & retail | 2026 |
| Faktion Books Ltd | Information & communication | 2024 |
| Falafel Cafe Limited | Hospitality | 2026 |
| Familia Ventures Ltd | Wholesale & retail | 2026 |
| Family Psychology UK Limited | Health & social care | 2018 |
| Faraday Keynes Limited | Professional & scientific | 2012 |
| Faralya Group Ltd | Wholesale & retail | 2025 |
| Farewell Hall West Farm Residents Management Company Ltd | Households | 2013 |
| Farmont L.P. | | 1988 |
| Farnley Mansion Limited | Hospitality | 2022 |
| Farrall Consulting Ltd | Information & communication | 2024 |
| Fast Charge (UK) Ltd | Construction | 2020 |
| Fast Homes NE Ltd | Real estate | 2025 |
| Fast Response Ltd | Construction | 2024 |
| Fatugkz Ltd | Wholesale & retail | 2025 |
| Favori Trade Ltd | Wholesale & retail | 2025 |
| Fawsco Consulting Limited | Professional & scientific | 2025 |
| FC Management NE Limited | Administrative & support | 2016 |
| FE Play Limited | Arts & recreation | 2023 |
| Feasibly Ltd | Professional & scientific | 2022 |
| Fellside Developments Ltd | Construction | 2026 |
| Fellview Fencing Northeast Ltd | Construction | 2023 |
| Fenchurch Properties (NE) Limited | Real estate | 2024 |
| Ferens Park Maintenance Limited | Households | 1995 |
| Festivals North East Limited | Arts & recreation | 2025 |
| FF Heating Ltd | Construction | 2025 |
| Fffh (1) Ltd | Information & communication | 2025 |
| FGS Properties (NE) Ltd | Real estate | 2020 |
| FGS Service Group Ltd | Administrative & support | 2025 |
| FHL Homes Limited | Real estate | 2025 |
| Fibretec Telecommunications Limited | Construction | 2020 |
| Fides Healthcare Limited | Administrative & support | 2025 |
| Fidra Consultancy Ltd | Professional & scientific | 2025 |
| Fielding and White Limited | Real estate | 2025 |
| Fight Record Ltd | Wholesale & retail | 2017 |
| Fiik Ltd | Hospitality | 2023 |
| Fika Coffee Roasters Ltd | Manufacturing | 2020 |
| Filament PR Ltd | Professional & scientific | 2013 |
| Films Remastered Ltd | Information & communication | 2024 |
| Filmutopia Ltd | Information & communication | 2024 |
| Filterwise Ltd | Professional & scientific | 2023 |
| Fin-Diemme UK Ltd | Manufacturing | 2020 |
| Fina Investments Ltd | Financial services | 2025 |
| Financial Business Solutions UK Limited | Professional & scientific | 2003 |
| Finantr Ltd | Information & communication | 2026 |
| Finch's Motor Repairs Ltd | Wholesale & retail | 2025 |
| Finchale Estates Limited | Real estate | 2014 |
| Findlay Harrison Properties Limited | Real estate | 2000 |
| Finley Bros Ltd | Water & waste | 2010 |
| Finley's TM Ltd | Construction | 2025 |
| Fiona Dent Network Limited | Professional & scientific | 2018 |
| Fire Door Training and Inspection Limited | Education | 2003 |
| Firewatch Fire Protection Ltd | Public administration | 2016 |
| First Choice Companies Group Limited | Information & communication | 2023 |
| First Class Utilities UK Ltd | Construction | 2022 |
| Firtree Swimming Ltd | Arts & recreation | 2025 |
| Fit Brands Ltd | Wholesale & retail | 2009 |
| Fit Food Diary Coaching Ltd | Health & social care | 2023 |
| Fivezerofive Audio Limited | Information & communication | 2015 |
| Fixed Mobiles and Vapes Limited | Wholesale & retail | 2024 |
| FJM Groundworks Limited | Construction | 2025 |
| FK Joinery Ltd | Construction | 2022 |
| FK United Limited | Wholesale & retail | 2025 |
| Flag Security Group Security Services and Training Limited | Administrative & support | 2026 |
| Flame Safe NE Ltd | Construction | 2015 |
| Flashlane Ltd | Wholesale & retail | 2025 |
| Flass House Ltd | Real estate | 2024 |
| Flat White Durham Limited | Hospitality | 2012 |
| Flawless Studios Limited | Information & communication | 2004 |
| FLC Durham Limited | Hospitality | 2010 |
| Fleethub Limited | Administrative & support | 2024 |
| Fleur Salon Ltd | Other services | 2014 |
| Flex-Able Holdings Ltd | Financial services | 2025 |
| Flex-Able Transport Ltd | Transport & logistics | 2025 |
| Flexability Fitness Ltd | Other services | 2025 |
| Flight Ranch Limited | Hospitality | 2025 |
| Flip Property Developments Limited | Real estate | 2020 |
| Flood Inns Limited | Hospitality | 2023 |
| Flou Global Ltd | Wholesale & retail | 2025 |
| Flow Assist Ltd | Information & communication | 2026 |
| Flow Business Services Ltd | Agriculture & fishing | 2018 |
| Flowers Enterprises Ltd | Other services | 2023 |