| Fans on Chain Limited | Information & communication | 2025 |
| Faraday Energy Ltd | Administrative & support | 2025 |
| Farolima Limited | Construction | 2021 |
| Farritec Ltd | Information & communication | 2019 |
| Fashion Flooring @ Home Ltd | Construction | 2019 |
| Fateh Dhami Ltd | Hospitality | 2016 |
| Fawkes Software Consultancy Ltd | Information & communication | 2020 |
| FC Property Management Limited | Real estate | 2012 |
| FD Immigration Limited | Professional & scientific | 2018 |
| FD Investment Group Ltd | Construction | 2020 |
| Fdca Limited | Professional & scientific | 2017 |
| Feral Forest Company Limited | Agriculture & fishing | 2026 |
| Ferndale RTM Co Limited | Households | 2012 |
| Fesli Ltd | Real estate | 2019 |
| FFF Harry Shepherd Limited | Arts & recreation | 2025 |
| Fids Prop Co Ltd | Real estate | 2025 |
| Fieldview Racing Ltd | Arts & recreation | 2021 |
| Fifth Chiltern Park (Management) Limited | Households | 1977 |
| Film Fifty LDA Limited | Arts & recreation | 2025 |
| Final Draft Publishing Ltd | Information & communication | 2011 |
| Financial & Strategy Services Ltd | Professional & scientific | 2012 |
| Financial Building Blocks Limited | Professional & scientific | 2024 |
| Financial Freedom Accountants Ltd | Professional & scientific | 2022 |
| Financial Freedom Club Ltd | Professional & scientific | 2024 |
| Fineall Consulting Ltd | Construction | 2019 |
| Finewood Homes Limited | Construction | 2016 |
| Finnet Consulting Ltd | Information & communication | 2022 |
| Finomisult Ltd | Information & communication | 2020 |
| Fiona Morris Consulting Limited | Professional & scientific | 2018 |
| Fire Guard Services Limited | Manufacturing | 2006 |
| Fire Networks Ltd | Information & communication | 2011 |
| Firebox Engineering Ltd | Manufacturing | 2025 |
| Firs Residents (Harpenden) Limited(The) | Households | 1968 |
| First Plumbing Ltd | Construction | 2023 |
| First Point Consultants (South East) Limited | Professional & scientific | 2010 |
| First Reflection Limited | Arts & recreation | 1986 |
| First Serve Accountants Limited | Extraterritorial | 2009 |
| Firstmd Limited | Professional & scientific | 2015 |
| Fish Homes Ltd | Real estate | 2012 |
| Fishermann Pubs Limited | Hospitality | 2020 |
| Fishpool Conservation Specialists Ltd | Real estate | 2015 |
| Fitzroy Goodwood Limited | Professional & scientific | 2022 |
| Five Dinners Limited | Hospitality | 2020 |
| Five Oaks London Ltd | Education | 2022 |
| Five Rivers Equity Limited | Financial services | 2009 |
| Five Rivers Group Limited | Financial services | 2011 |
| Five Rivers Ventures Limited | Financial services | 2021 |
| FKY Consultancy Limited | Professional & scientific | 2025 |
| Flamme Rouge Cycling Logistics Ltd | Wholesale & retail | 2020 |
| Flash Tiles Ltd | Construction | 2021 |
| Flash-Forward Services Limited | Professional & scientific | 2024 |
| Fleet Manifest Ltd | Information & communication | 2026 |
| Fleetriver Consulting Ltd | Professional & scientific | 2020 |
| Fletcher Housing Ltd | Real estate | 2024 |
| Flexible Offices Ltd | Administrative & support | 2016 |
| Flicker-Wellbeing C.I.C. | Information & communication | 2016 |
| FLJ Design Limited | Professional & scientific | 2022 |
| FLO Payment Services Ltd | Financial services | 2026 |
| Flyfox Services Limited | Information & communication | 2021 |
| FLŌ Fitness Ltd | Arts & recreation | 2025 |
| FM Golf Limited | Education | 2015 |
| Fm-Qs Homes Limited | Real estate | 2024 |
| Fnction Ltd | Manufacturing | 2024 |
| Focused Management Limited | Professional & scientific | 2007 |
| Football FUN Factory (Community 125) Ltd Limited | Arts & recreation | 2024 |
| Footballher Limited | Education | 2024 |
| Forbes Hunt Search and Selection Limited | Administrative & support | 2009 |
| Forge Ahead Limited | Professional & scientific | 2021 |
| Formech International Limited | Manufacturing | 1994 |
| Forms Workwear Ltd | Wholesale & retail | 2025 |
| Forterra Advisors Ltd | Administrative & support | 2023 |
| Forza DI Marmi Ltd | Manufacturing | 2023 |
| Fountain Consultants Limited | Wholesale & retail | 2025 |
| Fourth Events Limited | Administrative & support | 2025 |
| FOX Connaught Limited | Hospitality | 2018 |
| FOX Excel Limited | Hospitality | 2018 |
| Fozziwig Limited | Real estate | 2022 |
| FR Medics Limited | Health & social care | 2023 |
| Franglais Property and Management Services Limited | Administrative & support | 2006 |
| Frankling & Oakley Ltd | Construction | 2018 |
| Frankly PR Ltd | Professional & scientific | 2010 |
| Franks Forestry Contractors Ltd | Agriculture & fishing | 2026 |
| Franks Forestry Ltd | Agriculture & fishing | 2006 |
| Frear LLP | | 2010 |
| Fredmoor Limited | Professional & scientific | 2015 |
| Freepen Interior Design Ltd | Construction | 2019 |
| Fresh Perspective Communications Limited | Professional & scientific | 2019 |
| Fresh Perspective Psychology Ltd | Education | 2021 |
| Friday Collective Ltd | Information & communication | 2021 |
| Friends of Tumaini Company Limited | Education | 2008 |
| From Babies With Love Foundation | Health & social care | 2011 |
| From Babies With Love Trading Ltd | Manufacturing | 2012 |
| Fruitjuice Holdings Ltd | Information & communication | 2021 |
| FS Talent Group Limited | Administrative & support | 2024 |
| Fucan Group Limited | Wholesale & retail | 2024 |
| Fugitive Film Production Ltd | Information & communication | 2022 |
| Full Access Media Limited | Information & communication | 2021 |
| Full Future Ltd | Information & communication | 2024 |
| Fungialert Limited | Professional & scientific | 2015 |
| Furzedown Management Company Limited | Households | 1978 |