| First Stop Couriers Limited | Transport & logistics | 2022 |
| First Stop Health Care Limited | Public administration | 2023 |
| First Storm Limited | Wholesale & retail | 2024 |
| First Street Management Company Limited | Real estate | 2010 |
| First Syrian Commercial Investment Ltd | Wholesale & retail | 2025 |
| First Telecommunications Limited | Information & communication | 2006 |
| First Thirst Ltd | Wholesale & retail | 2021 |
| First Time Pizza Ltd | Wholesale & retail | 2023 |
| First Touch Communications Limited | Financial services | 2002 |
| First Touch Marketing Ltd | Professional & scientific | 2021 |
| First United Line Limited | Extraterritorial | 2019 |
| First United Services Agency Ltd | Real estate | 2023 |
| First Utility Limited | Energy | 2004 |
| First Valet Limited | Wholesale & retail | 2017 |
| First Venture Limited | Hospitality | 2019 |
| First-Class Joinery Northwest Ltd | Construction | 2021 |
| First-Step Group Limited | Real estate | 2008 |
| FIRST4 Protection Ltd | Financial services | 2019 |
| FIRST4SPARES UK Ltd | Extraterritorial | 2011 |
| Firstbridge Trading Limited | Other services | 2023 |
| Firstcall DEN Ltd | Health & social care | 2026 |
| Firstcast Limited | Real estate | 1996 |
| Firstgen Surveyors Limited | Professional & scientific | 2021 |
| Firstlight Trust | Health & social care | 2012 |
| Firstline Plastering Limited | Health & social care | 2023 |
| Firstmind Ltd | Information & communication | 2020 |
| Firstplus Logistics Ltd | Transport & logistics | 2023 |
| Firstpoint Healthcare Limited | Administrative & support | 2007 |
| Firstpoint Homecare Limited | Health & social care | 2008 |
| Firstshop Limited | Real estate | 1997 |
| Firstsphere Property Management Limited | Professional & scientific | 1991 |
| Firststep Management Ltd | Construction | 2025 |
| Firstunicorn Ltd | Wholesale & retail | 2023 |
| Firstword Limited | Real estate | 1996 |
| Firswood Consulting Limited | Professional & scientific | 2026 |
| Firswood Digital Services Limited | Health & social care | 2018 |
| Firswood Estates Ltd | Real estate | 2022 |
| Firswood Properties Limited | Real estate | 2017 |
| Firswood Solutions Limited | Information & communication | 2011 |
| Firth Mortgage Brokers Ltd | Financial services | 2022 |
| Firth Vickers Centrispinning Limited | Manufacturing | 1924 |
| Firthfair Ltd | Extraterritorial | 2014 |
| Firyatna Ltd | Wholesale & retail | 2024 |
| Firyfly Ltd | Wholesale & retail | 2025 |
| Fiscalculate Ltd | Professional & scientific | 2023 |
| Fiscalframe Accounting Services Ltd | Professional & scientific | 2024 |
| Fischer Limited | Energy | 2025 |
| Fisconcept Ltd | Wholesale & retail | 2024 |
| Fisdeb Ltd | Information & communication | 2020 |
| Fish & Fire (Beswick) Ltd | Hospitality | 2021 |
| Fish & Flame (NW) Ltd | Hospitality | 2024 |
| Fish 'R' Friends Limited | Extraterritorial | 2021 |
| Fish Matters Food Ltd | Hospitality | 2026 |
| FISH2FISH Ltd | Wholesale & retail | 2021 |
| Fisheasy Limited | Wholesale & retail | 2023 |
| Fishel Estates Ltd. | Real estate | 2002 |
| Fisher Acoustics Ltd | Professional & scientific | 2015 |
| Fisher Group Services Ltd | Water & waste | 2026 |
| Fisher Scaffolding Limited | Construction | 2025 |
| Fishguard Bay Hotel Limited | Hospitality | 1967 |
| Fishlocks Flowers Limited | Wholesale & retail | 2018 |
| Fiskcourt Limited | Professional & scientific | 1990 |
| Fisticanucm Limited | Construction | 2026 |
| Fistinz Limited | Wholesale & retail | 2024 |
| Fit & Stitch Ltd | Other services | 2023 |
| Fit BEE Ltd | Transport & logistics | 2022 |
| Fit Body DOC Limited | Health & social care | 2016 |
| Fit Food Media Ltd | Hospitality | 2022 |
| Fit N FUN Limited | Other services | 2023 |
| Fit N Funky Gym (Atherton) Limited | Arts & recreation | 2017 |
| Fit Recruitment Ltd | Administrative & support | 2019 |
| FIT-4-LIFE INT Ltd | Manufacturing | 2023 |
| FIT4HOME Ltd | Wholesale & retail | 2013 |
| FIT4YOUWITHJUDY Limited | Arts & recreation | 2025 |
| Fitart Limited | Arts & recreation | 2017 |
| Fitasa Limited | Extraterritorial | 2008 |
| Fitasaboxer Limited | Extraterritorial | 2007 |
| Fitco NW Limited | Arts & recreation | 2025 |
| Fitedia Ltd | Wholesale & retail | 2011 |
| Fitfield (EOT) Limited | Financial services | 2020 |
| Fitforlive Ltd | Information & communication | 2024 |
| Fitfy Ltd | Information & communication | 2025 |
| Fitlane Ltd | Wholesale & retail | 2026 |
| Fitlebo Ltd | Wholesale & retail | 2024 |
| Fitness Assets (NO 2) Limited | Real estate | 2017 |
| Fitness Assets Limited | Real estate | 2017 |
| Fitness Circle Group Limited | Administrative & support | 2025 |
| Fitness With MOL Ltd | Other services | 2021 |
| Fitnessx Ltd | Information & communication | 2025 |
| Fitns Ltd | Arts & recreation | 2023 |
| Fitout O&M Ltd | Professional & scientific | 2020 |
| Fitpixels Ltd | Professional & scientific | 2012 |
| Fitpro Authority Consultants Limited | Other services | 2018 |
| Fits & Starts Consulting Ltd | Information & communication | 2015 |
| Fitspire Ltd | Extraterritorial | 2025 |
| Fitsync Solutions Limited | Information & communication | 2026 |
| Fittaviation Ltd | Transport & logistics | 2018 |
| Fitting Hub Ltd | Wholesale & retail | 2023 |
| Fittingin Ltd | Professional & scientific | 2026 |
| Fittonmillett Ltd | Professional & scientific | 2023 |