| Finesse BOY Enterprise Ltd | Information & communication | 2026 |
| Finmind Advisory Limited | Professional & scientific | 2025 |
| Fintuition Consulting Limited | Professional & scientific | 2023 |
| Fiona Taylor Limited | Health & social care | 2012 |
| FIR Park Cares Ltd | Health & social care | 2026 |
| Fire Chicken Ltd | Hospitality | 2026 |
| Fire Ledger Ltd | Public administration | 2021 |
| Fire P Ltd | Construction | 2023 |
| Fireant Networks Limited | Education | 2020 |
| Fireriskassessors Ltd | Public administration | 2017 |
| First Care Medics Ltd | Health & social care | 2022 |
| First Choice Building & Home Improvements Ltd | Construction | 2007 |
| First Choice Drainage Limited | Construction | 2024 |
| First Choice Drainage Solutions Limited | Construction | 2016 |
| First Choice Landscaping Ltd | Construction | 2024 |
| First Choice Property Solutions (London) Limited | Real estate | 2021 |
| First Choice Tail Lifts Limited | Wholesale & retail | 2022 |
| First Class Learning Harlow Ltd | Education | 2022 |
| First COG Holdings Ltd | Financial services | 2020 |
| First Jacobsen's Estate Management Company Limited | Households | 1975 |
| First Norwood Management Company Limited | Households | 1984 |
| First Ocean Park Management Co. Limited | Households | 1993 |
| First Phase Electrical & Maintenance Limited | Construction | 2024 |
| First Point Complex Care Limited | Health & social care | 2024 |
| First Point Healthcare Staffing Limited | Health & social care | 2014 |
| First Property & Investment Ltd | Real estate | 2023 |
| First Safety Consultant Ltd | Professional & scientific | 2024 |
| First Star Property Services Ltd | Real estate | 2021 |
| First Stop I.T. Limited | Information & communication | 2000 |
| First Time Consulting Limited | Information & communication | 2012 |
| First Weybrook Residents Association (Guildford) Limited | Households | 1988 |
| Firstwoods Limited | Manufacturing | 2025 |
| Fish Fabrications Ltd | Administrative & support | 2018 |
| Fisherhuda Services Limited | Professional & scientific | 2026 |
| Fishing in Mind CIC | Health & social care | 2024 |
| Fit Busy MUM Ltd | Wholesale & retail | 2026 |
| Fitmums Network Limited | Wholesale & retail | 2019 |
| Fitter CP Limited | Construction | 2024 |
| Fitter Home Limited | Construction | 2012 |
| Fitwear Enterprise Ltd | Wholesale & retail | 2021 |
| Five Bears Vape Co Ltd | Wholesale & retail | 2025 |
| Five Lakes Fishery Ltd | Agriculture & fishing | 2018 |
| Five SIX Ltd | Wholesale & retail | 2019 |
| Five Star Heating (South East) Limited | Professional & scientific | 2015 |
| Fiveways Group Holdings Ltd | Financial services | 2018 |
| FIX and Flip Construction Ltd | Construction | 2024 |
| FIX and Flip Maintenance and Property Service Ltd | Construction | 2025 |
| FIX-8 Bidz Limited | Other services | 2026 |
| Fixi Ltd | Wholesale & retail | 2026 |
| Fixit & Trade Hub Ltd | Construction | 2025 |
| Fizeau Limited | Information & communication | 2017 |
| FJ Medica Ltd | Health & social care | 2023 |
| FJD Ltd | Administrative & support | 2023 |
| FK Builders Limited | Construction | 2025 |
| FL7 Academy Ltd | Education | 2026 |
| Flash Sales Global Ltd | Wholesale & retail | 2025 |
| Flashpoint Ltd | Education | 2022 |
| Flat Care (New Inn) Limited | Households | 1975 |
| Flat PAC MAN Ltd | Manufacturing | 2024 |
| Flatsix Detailing Limited | Professional & scientific | 2019 |
| Flawless Figures Aesthetics Limited | Other services | 2024 |
| Flindall Entity Ltd | Transport & logistics | 2024 |
| FLINDALL3 Limited | Transport & logistics | 2026 |
| Flintline Ltd | Professional & scientific | 2026 |
| Flirt PR Limited | Other services | 2009 |
| Floorlite Flooring Ltd | Construction | 2017 |
| Florance Property Ltd | Real estate | 2025 |
| Florentina Dumitru Ltd | Health & social care | 2021 |
| Flormetal Limited | Water & waste | 2024 |
| Flow Academies Ltd | Arts & recreation | 2021 |
| Flow Mate Ltd | Construction | 2026 |
| Flush & Flow (Parts) Limited | Wholesale & retail | 2026 |
| Flux IT Hardware Ltd | Wholesale & retail | 2012 |
| FLY Eagle Ltd | Administrative & support | 2012 |
| FLY Sports (UK) Limited | Manufacturing | 2012 |
| Flying Seagull Limited | Administrative & support | 2019 |
| Flyren Cargo Ltd | Transport & logistics | 2025 |
| FMB Lofts Limited | Real estate | 2019 |
| FMC Quality Ltd | Construction | 2023 |
| FMG Transport Ltd | Construction | 2024 |
| FMJ Continental Ltd | Wholesale & retail | 2023 |
| Fobizob Limited | Health & social care | 2024 |
| Foksi Ltd | Administrative & support | 2011 |
| Folabed Care Service Ltd | Health & social care | 2020 |
| Folajimi GP Limited | Health & social care | 2025 |
| Folami Consulting Limited | Professional & scientific | 2022 |
| Folar Properties Ltd | Hospitality | 2024 |
| Foltech IT Consulting Ltd | Information & communication | 2010 |
| Fomwauk Ltd | Education | 2015 |
| Fondong Limited | Health & social care | 2017 |
| Fone N Repairs Trade Ltd | Wholesale & retail | 2025 |
| Fone N Repairs Trading Ltd | Wholesale & retail | 2024 |
| Food Belly Group Ltd | Health & social care | 2020 |
| Foodsmart Ltd | Wholesale & retail | 2026 |
| Football Focused Excellence (Community) CIC | Arts & recreation | 2024 |
| Football Focused Excellence Ltd | Education | 2022 |
| Football FUN Factory (Community 134) Limited | Arts & recreation | 2024 |
| Forensic GAP Limited | Administrative & support | 2025 |
| Foresight 1967 Ltd | Arts & recreation | 2024 |
| Foresight Strategic Solutions Ltd | Professional & scientific | 2025 |