| Field Financial Planning Limited | Professional & scientific | 2016 |
| Fierce Muay Thai Ltd | Arts & recreation | 2020 |
| Fife Domi Audiology Specsavers Limited | Wholesale & retail | 2023 |
| Fife Domiciliary Specsavers Limited | Wholesale & retail | 2015 |
| Fifth Cipher Limited | Information & communication | 2026 |
| Filkins Holdings Limited | Financial services | 2021 |
| Filton Specsavers Hearcare Limited | Wholesale & retail | 2013 |
| Filton Specsavers Limited | Wholesale & retail | 2002 |
| FIN and Olive Decorating and Carpentry Ltd | Manufacturing | 2025 |
| Finam Engineering Ltd | Manufacturing | 2024 |
| Finam Property Services Ltd | Real estate | 2024 |
| Finance a Vehicle Ltd | Wholesale & retail | 2015 |
| Financial Consultancy Group Limited | Financial services | 2000 |
| Finaro Accountancy Limited | Professional & scientific | 2025 |
| Finch Integrated Services Ltd | Construction | 2026 |
| Find Recruitment Group Limited | Administrative & support | 2021 |
| Find Your North Limited | Administrative & support | 2017 |
| Finder AI Ltd | Professional & scientific | 2025 |
| Fineair Ventilation Services Limited | Manufacturing | 2019 |
| Fingal Consulting Limited | Professional & scientific | 2005 |
| Fingerprint Estates Limited | Construction | 2025 |
| Fingerprint Holdings Limited | Financial services | 2025 |
| Fingerprint Studios Architects Limited | Professional & scientific | 2021 |
| Finnie's Water Sports Equipment Limited | Wholesale & retail | 2025 |
| Fiora Health Ltd | Information & communication | 2026 |
| Fire & Fries BBQ Ltd | Hospitality | 2024 |
| Fire & Grill Limited | Hospitality | 2025 |
| Fire and Safety Testing Limited | Public administration | 2013 |
| Firefinch Media Group Limited | Information & communication | 2025 |
| Firefly Funerals Limited | Other services | 2019 |
| Firenza Fire Prevention Limited | Public administration | 2026 |
| Firesight Technologies Ltd | Information & communication | 2025 |
| Firmitas Ltd | Wholesale & retail | 2025 |
| Firs Farm Turbine Limited | Energy | 2014 |
| First Beeline Buses Limited | Transport & logistics | 1987 |
| First Care Homes Cambridge Holdings Limited | Financial services | 2025 |
| First Care Homes Ipswich Holdings Limited | Financial services | 2025 |
| First Care Homes Limited | Extraterritorial | 2012 |
| First Cheshire Properties Limited | Construction | 2010 |
| First Concept Design UK Ltd | Other services | 2019 |
| First Court Limited | Other services | 2022 |
| First Hampshire & Dorset Limited | Transport & logistics | 1986 |
| First Nurse Ltd | Health & social care | 2024 |
| First Point Recruitment Ltd | Administrative & support | 2022 |
| Firth Castle Ltd | Real estate | 2018 |
| Firth Park Specsavers Limited | Wholesale & retail | 2018 |
| Firth Property Anglesey Limited | Real estate | 2024 |
| Fish Guidance Systems Limited | Administrative & support | 1994 |
| Fishlife Pond Services Limited | Administrative & support | 2020 |
| Fishponds Specsavers Limited | Wholesale & retail | 2002 |
| Fitzrovia Enterprises Ltd | Wholesale & retail | 2009 |
| Five Boroughs Pizza Limited | Hospitality | 2023 |
| Five Eggs Media Ltd | Information & communication | 2012 |
| Fivesnakes Ltd | Professional & scientific | 2024 |
| FIX and Fit Plumbing and Heating Ltd | Construction | 2022 |
| FIX Your Group Limited | Professional & scientific | 2026 |
| Fixall Marine Ltd | Information & communication | 2006 |
| Fixeroo Ltd | Extraterritorial | 2024 |
| Fixy Software Solutions Limited | Information & communication | 2010 |
| FJD Wealth Management Ltd | Professional & scientific | 2024 |
| FL Studios LLP | | 2025 |
| Flame 'N' Pizza Ltd | Hospitality | 2025 |
| Flameshield Limited | Extraterritorial | 2017 |
| Flashchef Limited | Hospitality | 2011 |
| Flatdale Limited | Households | 1999 |
| Fleet Services South West Ltd | Professional & scientific | 2023 |
| Fleet Specsavers Limited | Wholesale & retail | 1995 |
| Fleet Visionplus Limited | Wholesale & retail | 1995 |
| Fleetlands Flying | Arts & recreation | 2007 |
| Fletcher Plant Services Limited | Manufacturing | 2017 |
| Fletcher Properties Limited | Real estate | 2020 |
| Fleury Capital Ltd. | Other services | 2011 |
| Flexirent IBC Rental Specialists Limited | Administrative & support | 2012 |
| Flight and Stay Limited | Administrative & support | 2024 |
| Flight Data Consulting Limited | Professional & scientific | 2022 |
| Flint Developments '12 Limited | Construction | 2012 |
| Flint Specsavers Limited | Wholesale & retail | 2007 |
| Flint Visionplus Limited | Wholesale & retail | 2007 |
| Flixglow Limited | Extraterritorial | 2005 |
| FLO Renovations Ltd | Construction | 2024 |
| Flobea Consulting Limited | Construction | 2024 |
| Flojack Limited | Manufacturing | 2025 |
| Florence and Walter Limited | Information & communication | 2025 |
| Flow (Services) Ltd | Construction | 2014 |
| Fluid Design & Development Limited | Construction | 2016 |
| Fluid Film Technologies Ltd | Agriculture & fishing | 2023 |
| Fluid Software Dynamics Ltd | Information & communication | 2026 |
| Flux PHE Limited | Construction | 2008 |
| Flyingcat Holding Limited | Real estate | 2026 |
| Flyingcat Property Limited | Real estate | 2026 |
| Fmmn Properties Limited | Real estate | 2023 |
| FMS Asset Management Ltd | Financial services | 2009 |
| Focus International 2023 Limited | Wholesale & retail | 2023 |
| Folkestone Specsavers Hearcare Limited | Wholesale & retail | 2022 |
| Folkestone Specsavers Limited | Wholesale & retail | 2007 |
| Folkestone Visionplus Limited | Wholesale & retail | 2007 |
| Folland Aerotech Limited | Professional & scientific | 2011 |
| Followspot Limited | Information & communication | 2025 |
| Fone Centre IT Limited | Wholesale & retail | 2023 |
| Food Harvest Patisserie Limited | Wholesale & retail | 2025 |