| First Mode IPP Limited | Professional & scientific | 2022 |
| First Option Housing Ltd | Real estate | 2026 |
| First Peak Ltd | Health & social care | 2020 |
| First Peninsula Corporation Limited | Professional & scientific | 2006 |
| First Plus Training Ltd | Education | 2025 |
| First Point Cleaning and Maintenance Ltd | Administrative & support | 2019 |
| First Point Foods Ltd | Wholesale & retail | 2020 |
| First Point Housing Limited | Real estate | 2026 |
| First Point Real Estate Ltd | Real estate | 2025 |
| First Practice Healthcare Ltd | Health & social care | 2010 |
| First Premier Motors Limited | Wholesale & retail | 2018 |
| First Rate Housing Limited | Real estate | 2020 |
| First Rate Ltd | Administrative & support | 2013 |
| First Response (First AID) Limited | Administrative & support | 2006 |
| First Ridding Property Management Company Limited | Households | 1989 |
| First Roots Day Nursery Ltd | Health & social care | 2026 |
| First Steps 4WARD Ltd | Hospitality | 2025 |
| First Steps Babywear UK Ltd | Wholesale & retail | 2025 |
| First Storage Solutions Ltd | Other services | 2026 |
| First Supermarket Ltd | Wholesale & retail | 2025 |
| First Tidbury (Yvonne Park) Management Company Limited | Households | 1982 |
| First Time Quality Ltd | Construction | 2026 |
| First to Work Ltd | Administrative & support | 2016 |
| FIRST2CARE Ltd | Administrative & support | 2024 |
| FIRST4 Driveways Limited | Construction | 2025 |
| FIRST4LOCUM Limited | Health & social care | 2019 |
| FIRST4TEACH Ltd | Administrative & support | 2024 |
| Firstborn Group Limited | Information & communication | 2020 |
| Firstbuild Construction Ltd | Construction | 2023 |
| Firstcall Facilities Limited | Construction | 2005 |
| Firstcall Photo Limited | Wholesale & retail | 1989 |
| Firstcallhouses Ltd | Real estate | 2026 |
| Firstclass Ventures Limited | Extraterritorial | 2016 |
| Firsthousinggroup Limited | Hospitality | 2017 |
| Firstlight Housing Ltd | Hospitality | 2025 |
| Firstpress (Plastic Moulders) Limited | Manufacturing | 1985 |
| Firstrock Group Ltd | Professional & scientific | 2020 |
| Firstrock Ltd | Real estate | 2020 |
| Firth Carpets Limited | Extraterritorial | 1966 |
| Firth Cleveland Limited | Extraterritorial | 1953 |
| FIS Clouds Ltd | Information & communication | 2019 |
| FIS Forward Housing Limited | Real estate | 2018 |
| FIS Suppliers Limited | Manufacturing | 2018 |
| Fisa Health Ltd | Wholesale & retail | 2025 |
| Fiscaloo U.K Limited | Professional & scientific | 2018 |
| Fischer Carlsen Limited | Information & communication | 2019 |
| Fish & Chips Classical Kebab House Ltd | Hospitality | 2020 |
| Fish and Chips Classic Ltd | Hospitality | 2022 |
| Fish Cave Limited | Wholesale & retail | 2023 |
| Fish Trans Ltd | Extraterritorial | 2018 |
| Fish Wholesalers (UK) Ltd | Wholesale & retail | 2017 |
| Fishco Fine Foods Limited | Wholesale & retail | 2002 |
| Fisher & Gimson (Builders) Limited | Construction | 2011 |
| Fisher Aerospace Limited | Professional & scientific | 2017 |
| Fisher Automotive Limited | Extraterritorial | 2017 |
| Fisher Catering Limited | Hospitality | 2025 |
| Fisher Craythorn Ltd | Construction | 2022 |
| Fisher Micropub Ltd | Hospitality | 2026 |
| Fisher Specialist Vehicle Solutions Limited | Information & communication | 2016 |
| Fisher Street (Surgery) Limited | Real estate | 2006 |
| Fisher SVS Limited | Extraterritorial | 2016 |
| Fisheries Management Limited | Other services | 2026 |
| Fishers (Black Country) Limited | Real estate | 2020 |
| Fishers (Harborne) Limited | Real estate | 2011 |
| Fishers (Wollaston) Limited | Real estate | 2024 |
| Fishing Limited | Wholesale & retail | 2004 |
| Fishing Village Company Ltd | Hospitality | 2024 |
| Fishworks Restaurants Limited | Hospitality | 2011 |
| Fisseha Limited | Information & communication | 2025 |
| Fistix Limited | Wholesale & retail | 2026 |
| Fit (North East) Limited | Information & communication | 2013 |
| Fit 4 Primary Ltd | Health & social care | 2022 |
| Fit 4 Sport Specialist PE and Sports Provider CIC | Other services | 2018 |
| Fit Box Clubs Ltd | Arts & recreation | 2019 |
| Fit Brands (UK) Ltd | Wholesale & retail | 2014 |
| Fit Property Limited | Construction | 2023 |
| FIT-4-SCHOOLS (UK) Ltd | Arts & recreation | 2014 |
| FIT4BUSINESS Limited | Financial services | 1996 |
| FIT4SPORT Specialist Sports and Fitness Provider Ltd | Hospitality | 2019 |
| FITBOX25 Limited | Arts & recreation | 2017 |
| Fitc Ltd | Information & communication | 2023 |
| Fitdripvibe Limited | Wholesale & retail | 2025 |
| Fitkit UK Properties Limited | Real estate | 2017 |
| Fitmc Ltd | Information & communication | 2024 |
| Fitness & Wellbeing PIT Ltd | Arts & recreation | 2026 |
| Fitness 4 Life Gym CIC | Other services | 2013 |
| Fitness and Entertainment Activities Ltd | Arts & recreation | 2016 |
| Fitness Extraordinaire Limited | Health & social care | 2017 |
| Fitness Factory II Ltd | Arts & recreation | 2004 |
| Fitness Finance Alliance Ltd | Arts & recreation | 2018 |
| Fitness Freakz Limited | Health & social care | 2016 |
| Fitness Leaders Limited | Arts & recreation | 2016 |
| Fitnesst Ltd | Arts & recreation | 2026 |
| Fitroad Ltd | Transport & logistics | 2023 |
| Fitsum Limited | Health & social care | 2022 |
| FITT4KIDS Limited | Education | 2022 |
| Fitterz Ltd | Wholesale & retail | 2025 |
| Fittie Committee Limited | Arts & recreation | 2025 |
| Fitting Farewell Limited | Manufacturing | 2009 |
| Fitting Models UK Limited | Administrative & support | 2016 |