| Frating Farm Services Limited | Construction | 2024 |
| FRB Property Limited | Real estate | 2018 |
| Fred & Drew Ltd | Administrative & support | 2024 |
| Frederick Nosakhare Limited | Health & social care | 2019 |
| Freds Sheds Limited | Wholesale & retail | 2001 |
| Free Fishing Limited | Agriculture & fishing | 2016 |
| Free Poultry Limited | Agriculture & fishing | 1996 |
| Free Spirit Fishing Limited | Wholesale & retail | 2003 |
| Free Thinkers C.I.C. | Health & social care | 2025 |
| Freedom Boat Adventures Community Interest Company | Administrative & support | 2020 |
| Freedom Body Art Ltd | Other services | 2026 |
| Freedom Funeral Services Limited | Health & social care | 2005 |
| Freedom Funerals Limited | Other services | 2007 |
| Freemasons Arms Brightlingsea Ltd | Hospitality | 2017 |
| Freemix Concrete (Essex) Ltd | Manufacturing | 2019 |
| Freesc Limited | Wholesale & retail | 2024 |
| Freight Unlocked Ltd | Transport & logistics | 2011 |
| Freightmap Logistics Solutions Limited | Administrative & support | 2013 |
| French in the City Languages Ltd | Education | 2010 |
| French Marine Motors Limited | Manufacturing | 1979 |
| French's Farm Limited | Extraterritorial | 1972 |
| Frenchie Flicks Ltd | Information & communication | 2025 |
| Fresh Beginnings UK C.I.C. | Administrative & support | 2017 |
| Fresh Fencing Limited | Administrative & support | 2023 |
| Fresh Fit Escapes Ltd | Administrative & support | 2019 |
| Fresh Fitness Training Ltd | Arts & recreation | 2018 |
| Fresh Fruit VEG Ltd | Wholesale & retail | 2023 |
| Fresh Property Lets Ltd | Real estate | 2023 |
| Fresh Scenery Cleaning and Pet Care Ltd | Administrative & support | 2025 |
| Freshogo Ltd | Wholesale & retail | 2026 |
| Freshpac Teas and Coffees Limited | Wholesale & retail | 2006 |
| Freshwater Designs Limited | Hospitality | 2023 |
| Freston Properties Limited | Construction | 1990 |
| Frewell Holdings Limited | Wholesale & retail | 2025 |
| Friars Farm Kennels & Cattery Limited | Administrative & support | 2003 |
| Friday's Child Associates Ltd | Administrative & support | 2013 |
| Friendly Finishing Solutions Ltd | Construction | 2013 |
| Friendly Homes Limited | Construction | 2016 |
| Friends and Family Care Support Ltd | Health & social care | 2023 |
| Fright FIC Limited | Financial services | 2025 |
| Frimpsey Limited | Health & social care | 2019 |
| Frincon (Colchester) Limited | Real estate | 1938 |
| Frinton Road Butchers Limited | Wholesale & retail | 2016 |
| Frinton Tarmacadam and Paving Limited | Construction | 1997 |
| Frinton Textiles Ltd | Administrative & support | 2009 |
| Friscan Limited | Professional & scientific | 2018 |
| Fristling Hall Farm Limited | Agriculture & fishing | 2005 |
| FRM Plumbing & Heating Ltd | Construction | 2018 |
| Frodsham Enterprises Limited | Real estate | 2011 |
| Frog Electrical Ltd | Construction | 2017 |
| Frogfish Group Ltd | Professional & scientific | 2016 |
| Frogfish Investments Limited | Real estate | 2022 |
| Froggatt Resources Optimally Given Limited | Financial services | 2013 |
| Front 5 Associates Ltd | Administrative & support | 2024 |
| Frontier Fine Wines Ltd | Wholesale & retail | 2013 |
| Frontline Data Limited | Information & communication | 2005 |
| Frontline Leadership Group Ltd | Professional & scientific | 2025 |
| Frontline Training Solutions Limited | Education | 2003 |
| Frost Agency Limited | Information & communication | 2015 |
| Frostfire Design Limited | Manufacturing | 2018 |
| Frostfire Investments Ltd | Financial services | 2020 |
| Frostfire Limited | Manufacturing | 1998 |
| Frostfires Internet Limited | Information & communication | 2018 |
| Frsb Limited | Transport & logistics | 2025 |
| Frycorp Properties Limited | Professional & scientific | 2015 |
| FS Flooring Ltd | Construction | 2026 |
| FS Global Services Ltd | Wholesale & retail | 2025 |
| FS Hand Car Wash (Winnersh) Limited | Other services | 2018 |
| FS8 Colchester Ltd | Arts & recreation | 2025 |
| FSA Automotive Limited | Administrative & support | 2006 |
| FSG Homes Limited | Real estate | 2023 |
| Fubar Hair Collective Limited | Other services | 2007 |
| Fubar Taverns Ltd | Hospitality | 2016 |
| Fuel Cost Management Ltd | Administrative & support | 2025 |
| Fuel Your Fortress Ltd | Administrative & support | 2016 |
| Fuelflow Ltd | Wholesale & retail | 2026 |
| Fuelogic Ltd | Wholesale & retail | 2018 |
| Fuelogic Transport Ltd | Transport & logistics | 1977 |
| Fulgor Milano UK Limited | Extraterritorial | 2024 |
| Full Circle Maintenance Limited | Administrative & support | 2022 |
| Full Home Magic Ltd | Wholesale & retail | 2012 |
| Full House Chinese Food Limited | Hospitality | 2023 |
| Full House Foods Limited | Hospitality | 2025 |
| Full Program Golf Ltd | Administrative & support | 2023 |
| Fullcircle Concrete Ltd | Manufacturing | 2019 |
| Fullcircle Energy Ltd | Energy | 2012 |
| Fullers Auto Salvage Limited | Wholesale & retail | 2013 |
| Fullers Place Estate Management Company Limited | Real estate | 2016 |
| Fullfilled Ltd | Hospitality | 2019 |
| FUN & Sun Limited | Financial services | 2015 |
| FUN 4 Kids Colchester Limited | Health & social care | 2014 |
| FUN DOT Co Limited | Health & social care | 2017 |
| Funday Entertainment Ltd | Arts & recreation | 2000 |
| Fungi Evolution Limited | Wholesale & retail | 2024 |
| Funky Sweets Limited | Wholesale & retail | 2002 |
| Funland Amusements Limited | Administrative & support | 2025 |
| Funmise Kare Services Ltd | Health & social care | 2021 |
| Furniture Kingdom Limited | Real estate | 1993 |
| Furthermore Ltd | Information & communication | 2013 |
| Fused Electrical Installations Ltd. | Construction | 2017 |