| Felix and Hippocrates Ltd | Health & social care | 2013 |
| Felix Equestrian Ltd | Construction | 2023 |
| Felix Support Ltd | Professional & scientific | 2024 |
| Felixbritto Services Ltd | Administrative & support | 2017 |
| Felixstowe Accountancy & Bookkeeping Ltd | Professional & scientific | 2020 |
| Felixstowe and Suffolk Bowling Club Limited | Arts & recreation | 1948 |
| Felixstowe Care Homes for the Elderly Limited | Health & social care | 2007 |
| Felixstowe Electrical Services Ltd. | Extraterritorial | 2018 |
| Felixstowe Ferry Sailing Club Limited | Arts & recreation | 2016 |
| Felixstowe Glass Co Limited | Construction | 2002 |
| Felixstowe Nursery School Ltd. | Education | 1977 |
| Felixstowe Padel Limited | Arts & recreation | 2026 |
| Felixstowe Port Users' Association Limited | Administrative & support | 1977 |
| Felixstowe Road Chiropractic Clinic Limited | Health & social care | 2011 |
| Felixstowe Rowing Club Ltd | Arts & recreation | 2020 |
| Felixtrans Ltd | Transport & logistics | 2010 |
| Fellowes Electrical Ltd | Construction | 2018 |
| Fellows Farm Ltd | Agriculture & fishing | 2024 |
| Fellows Tilers Ltd | Construction | 2023 |
| Fellowship Freight Ltd | Transport & logistics | 2019 |
| Femtosize Ltd | Professional & scientific | 2019 |
| FEN View Properties Ltd | Real estate | 2024 |
| Fena Healthcare Ltd | Health & social care | 2023 |
| Fena Limited | Hospitality | 2021 |
| Fenners Productions Limited | Information & communication | 2010 |
| Fensurv Limited | Construction | 2023 |
| Ferantis Ltd | Information & communication | 2025 |
| Ferens Pertwee Ltd | Professional & scientific | 2021 |
| Fern Hair Ltd | Other services | 2022 |
| Ferryboat-Felixstowe-P-C-Ashling Limited | Hospitality | 2025 |
| Fertilia AI Ltd | Information & communication | 2025 |
| Festation Ltd | Information & communication | 2025 |
| Fevura Consulting Ltd | Professional & scientific | 2025 |
| FGH Motorhomes Ltd | Manufacturing | 2018 |
| Fharmer Ltd | Information & communication | 2024 |
| FHS Bricklaying Contractors Ltd | Construction | 2020 |
| FHS Building Services Ltd | Construction | 2021 |
| FHV Solutions Ltd | Construction | 2025 |
| Fibre Network Connections Ltd | Information & communication | 2016 |
| Fibrecomms Ltd | Construction | 2019 |
| Fibreguard Limited | Construction | 2019 |
| Fibresof Solutions Limited | Information & communication | 2019 |
| Fickle and Hound Limited | Wholesale & retail | 2024 |
| Fidelity Consultancy Services Ltd | Professional & scientific | 2015 |
| Field & Form Ltd | Construction | 2025 |
| Fieldfare Meadow (Badwell ASH) Management Company Limited | Households | 2022 |
| Fieldgate Reach (Gillingham) Management Company Limited | Households | 2020 |
| Fieldway Assets Ltd | Real estate | 2021 |
| Fieraru DZ Limited | Construction | 2025 |
| Fika Communications Ltd | Professional & scientific | 2018 |
| Filao Properties Ltd | Real estate | 2025 |
| Filaret Shine Cleaning Limited | Administrative & support | 2025 |
| Filips Builders Ltd | Construction | 2019 |
| Film and Video Transfers Limited | Information & communication | 2007 |
| Film Suffolk C.I.C. | Information & communication | 2014 |
| Filmont Holding LP | | 2021 |
| Filters Antennas Support Limited | Manufacturing | 2019 |
| Fina Construction Ltd | Construction | 2023 |
| Fina Group Ltd | Financial services | 2023 |
| Fina Management Ltd | Households | 2023 |
| Fina Properties Ltd | Real estate | 2023 |
| Financial First Aiders Ltd | Education | 2026 |
| Financial Synergy Ltd | Financial services | 1997 |
| Finch Futures Limited | Real estate | 2019 |
| Finchkam Ltd | Wholesale & retail | 2024 |
| Find (Families in Need) Limited | Health & social care | 2004 |
| Find-A-Job (East Anglia) Limited | Administrative & support | 1970 |
| Find-A-Job (Ipswich) Holdings Ltd | Financial services | 2008 |
| Fine Book Cellar Limited | Wholesale & retail | 2022 |
| Fine Form Design Studios Limited | Administrative & support | 2009 |
| Fine Form Studio Ltd | Administrative & support | 2025 |
| Fine Tune Solutions Ltd. | Information & communication | 1991 |
| Finest Cars Operator Ltd | Transport & logistics | 2024 |
| Finicky's Hair Design Limited | Other services | 2001 |
| Finish 1ST Ltd | Manufacturing | 2017 |
| Finish Line Bathrooms Ltd | Construction | 2013 |
| Finorminal Roots CIC | Health & social care | 2026 |
| Finstech Ltd | Information & communication | 2020 |
| Finwell Community Platform Limited | Information & communication | 2026 |
| Fiona Parsons Environmental Consultancy Limited | Other services | 2005 |
| FIR Tree Farm Stables Limited | Agriculture & fishing | 2025 |
| Fircroft Hairdressing Limited | Other services | 2018 |
| Fircroft Medical Supplies Ltd | Wholesale & retail | 2024 |
| Fire Alarm CAD Ltd | Construction | 2022 |
| Fire and Air Services Limited | Professional & scientific | 2008 |
| Fire and KIN Ltd | Hospitality | 2026 |
| Fire Door Installations Ltd | Construction | 2022 |
| Fire Products Ltd | Construction | 2025 |
| Firebronds Ltd | Administrative & support | 2024 |
| Firecracker Creative Limited | Arts & recreation | 2012 |
| Firefly People UK Ltd | Administrative & support | 2021 |
| Fireglobe Limited | Construction | 2010 |
| Firehawk Software Ltd | Information & communication | 2026 |
| Firelight Pages Ltd | Manufacturing | 2026 |
| Firepower Management Limited | Professional & scientific | 2003 |
| Firesite (Eastern) Limited | Construction | 1991 |
| Firm Foundation Estates Limited | Real estate | 2023 |
| Firs Glamping Limited | Hospitality | 2018 |
| First Block Ltd | Information & communication | 2023 |
| First Candies UK Ltd | Hospitality | 2025 |