| Firstcare Nottingham Limited | Wholesale & retail | 2022 |
| Firstcourse-Medical LLP | | 2001 |
| Firstpoint (Atlas) Management Company Limited | Households | 2006 |
| Firstrow Consulting Ltd | Professional & scientific | 2026 |
| Firsure Limited | Real estate | 1980 |
| Firth Homes Limited | Construction | 2022 |
| Firthy's Traffic Management Ltd | Construction | 2014 |
| Firway Homes Ltd | Construction | 2023 |
| Fish Bar Ltd | Hospitality | 2026 |
| Fish Bit's Express Ltd | Hospitality | 2025 |
| Fish Law and Property Limited | Professional & scientific | 2018 |
| Fisher Enterprises Limited | Manufacturing | 2022 |
| Fishing Tackle & Bait Shop Limited | Wholesale & retail | 2019 |
| Fishlake Investments Limited | Financial services | 2022 |
| Fishlake Property Ltd | Real estate | 2005 |
| Fishlake Renewables Ltd | Professional & scientific | 2023 |
| Fit & Wild Ltd | Agriculture & fishing | 2025 |
| Fit 4 Life (Ackworth) Limited | Arts & recreation | 2015 |
| Fit 4 Life Fitness Ltd | Real estate | 2025 |
| Fit Group Holdings Limited | Professional & scientific | 2019 |
| Fit Itree Ltd | Agriculture & fishing | 2025 |
| Fitcheck Ltd | Information & communication | 2026 |
| Fite Consultancy Ltd | Professional & scientific | 2024 |
| Fite Holdings Ltd | Financial services | 2026 |
| Fitrite Fencing & Decking Limited | Manufacturing | 2010 |
| Fitz Electrical Ltd | Manufacturing | 2015 |
| Fitz Properties (Doncaster) Limited | Real estate | 2022 |
| Fitz Properties Ltd | Real estate | 2022 |
| Fitzwilliam Golocal Ltd | Wholesale & retail | 2026 |
| Fitzy Resourcing Ltd | Construction | 2024 |
| Five Oceans Consulting Limited | Professional & scientific | 2013 |
| Five Oceans Spaces Limited | Construction | 2014 |
| Five Star Social Care Limited | Administrative & support | 2014 |
| Fivestar Garage Doncaster Limited | Wholesale & retail | 2018 |
| FIX ALL Roofing & Gutters Ltd | Construction | 2026 |
| Fixed and Finished Ltd | Construction | 2025 |
| Fiximer Ltd | Manufacturing | 2019 |
| Fixnet Services Ltd | Construction | 2025 |
| Fiyin Cares Limited | Health & social care | 2021 |
| Fizzah Ahmad Optics Limited | Health & social care | 2016 |
| FJP Capital Ltd | Construction | 2019 |
| Fkfibre Ltd | Extraterritorial | 2022 |
| FKH & Co Ltd | Health & social care | 2021 |
| FKI Retford Limited | Professional & scientific | 1898 |
| Flagship Property Services Ltd | Construction | 2020 |
| Flagship Renewables Ltd | Construction | 2023 |
| Flamelight Electrics Limited | Manufacturing | 1999 |
| Flamiv Limited | Transport & logistics | 2021 |
| Flarepath.Com Limited | Information & communication | 2000 |
| Flash Cleans Ltd | Administrative & support | 2023 |
| Flash Direct Ltd | Information & communication | 2021 |
| Flash Find Store Ltd | Wholesale & retail | 2025 |
| Flashfit Mobile Tyres Ltd | Wholesale & retail | 2024 |
| Flaterin Ltd | Construction | 2022 |
| Flavour District Ltd | Hospitality | 2026 |
| Flawless Interiors & Training Ltd | Construction | 2013 |
| Fledglings (Rossington) Ltd | Education | 2021 |
| Fledglings Day Nursery Ltd | Education | 2017 |
| Fledglings Thorne Ltd | Health & social care | 2024 |
| Fleet Cars Direct LLP | | 2017 |
| Fleet Compliance Limited | Professional & scientific | 2010 |
| Fleet Web Hosting Ltd | Other services | 2009 |
| Fleet-Motion Ltd | Wholesale & retail | 2026 |
| Fleethaven Mobility Ltd | Extraterritorial | 2026 |
| Fletcher & Harrison Limited | Administrative & support | 2017 |
| Flex Travel Ltd | Extraterritorial | 2025 |
| Flex Wellbeing & Fitness Limited | Arts & recreation | 2025 |
| Flexilogix Ltd | Professional & scientific | 2025 |
| Flexisys Limited | Wholesale & retail | 2024 |
| Flexor Limited | Construction | 2003 |
| Flexshft Limited | Information & communication | 2025 |
| Flexxyb Plumbing Ltd | Construction | 2025 |
| Flicks Media Video Productions Limited | Professional & scientific | 2000 |
| Flindt Foods Ltd | Hospitality | 2024 |
| Flint Build Limited | Construction | 2010 |
| Flint Harris Ltd | Arts & recreation | 2025 |
| Flint R E Limited | Real estate | 2022 |
| Flip Master Holdings Limited | Real estate | 2024 |
| Flit Operations Ltd | Administrative & support | 2025 |
| Flnfitness Limited | Other services | 2026 |
| FLO Distribution Ltd | Administrative & support | 2017 |
| Flo-Fill Limited | Manufacturing | 2012 |
| Flock and Fillings Limited | Manufacturing | 2025 |
| Floorserve Ltd | Construction | 1997 |
| Floortrain (GB) Limited | Administrative & support | 2008 |
| Floortrain (International) Limited | Extraterritorial | 2008 |
| Floortrain (UK) Limited | Extraterritorial | 2008 |
| Floral Cleaning Ltd | Administrative & support | 2025 |
| Floresco Wealth Management Limited | Professional & scientific | 2013 |
| Florida Cosmetics Ltd | Wholesale & retail | 2026 |
| Florida Tanning (Armthorpe) Ltd | Other services | 2022 |
| Florida Tanning (Stainforth) Ltd | Other services | 2024 |
| Florida Tanning Ltd | Other services | 2019 |
| Florida Tanning Salon LLP | | 2024 |
| Florin Harlisca Ltd | Transport & logistics | 2024 |
| Florin Sofi Trans Ltd | Transport & logistics | 2024 |
| Floriologie Limited | Wholesale & retail | 2016 |
| Flossify Ltd | Health & social care | 2023 |
| Flour & Whisk Ltd | Extraterritorial | 2026 |
| Flourish Enterprises Community Interest Company | Health & social care | 2014 |