| Field Forge Limited | Information & communication | 2024 |
| Field Office Ltd | Professional & scientific | 2024 |
| Fieldfisher (N.I.) LLP | | 2025 |
| Fielding Admin Services Ltd | Administrative & support | 2012 |
| Fifty Talents Consultancy Limited | Professional & scientific | 2017 |
| Fifty Two East Limited | Financial services | 2022 |
| Fiftyone Healthcare Limited | Health & social care | 2012 |
| Figado Limited | Health & social care | 2012 |
| Fight Academy Ireland (2015) C.I.C. | Arts & recreation | 2015 |
| Fighting Words Northern Ireland | Education | 2016 |
| Figure This Limited | Education | 2024 |
| Filbrit Healthcare Ltd | Health & social care | 2023 |
| Filbrit Properties Ltd | Real estate | 2025 |
| Fileservice Limited | Administrative & support | 1992 |
| Fill Marketing Limited | Professional & scientific | 2018 |
| Fillluck Trade Limited | Wholesale & retail | 2025 |
| Film and Media Catering Limited | Hospitality | 2023 |
| Film Collectables Competitions Limited | Arts & recreation | 2025 |
| Filo Heart Beat International Ltd | Administrative & support | 2017 |
| FIN Holdings Ltd | Financial services | 2020 |
| Finaghy Asset Holdings Ltd | Financial services | 2026 |
| Finaghy Cleaning & Support Services Limited | Administrative & support | 2011 |
| Finaghy Dental Practice Ltd | Health & social care | 2010 |
| Finaghy Management Company Limited | Households | 2001 |
| Finaghy Park Gardens Ltd | Households | 2020 |
| Finaghy Properties Limited | Real estate | 2017 |
| Finaghy Road South Management Limited | Households | 2011 |
| Finaghy South Ltd | Health & social care | 2025 |
| Final Frame Pictures Ltd | Information & communication | 2025 |
| Finance Matters (NI) Limited | Financial services | 2005 |
| Financial Prospects (N.I.) Ltd | Professional & scientific | 2017 |
| Finao Limited | Financial services | 2016 |
| Finbeing Ltd | Information & communication | 2025 |
| Finchmere Services Ltd | Manufacturing | 2021 |
| Fine Focus Limited | Health & social care | 2023 |
| Fine Point Films Ltd | Information & communication | 2012 |
| Fine Point Group | Financial services | 2020 |
| Fine Point Pictures Limited | Information & communication | 2019 |
| Fine View Farm Limited | Agriculture & fishing | 2024 |
| Fine-Tuning Limited | Information & communication | 2020 |
| Finegan Gibson Ltd | Professional & scientific | 2012 |
| Finest Fire Security Ltd | Administrative & support | 2021 |
| Finlay Corporate Consulting Limited | Professional & scientific | 2025 |
| Finlay Graham Property Ltd | Real estate | 2013 |
| Finlay Wealth Management LLP | | 2011 |
| Finlay Wilson Wealth Management Ltd | Financial services | 2026 |
| Finmer Ltd | Real estate | 2017 |
| Finn Therapeutics Ltd | Professional & scientific | 2020 |
| Finnegan Consulting Limited | Professional & scientific | 2025 |
| Finntastic Ltd | Information & communication | 2018 |
| Finteco Ltd | Professional & scientific | 2018 |
| Fintra Bay Fishing Ltd | Agriculture & fishing | 2024 |
| Fintx Ltd | Other services | 2026 |
| Finucane Toner Limited | Professional & scientific | 2014 |
| Finzoic Ltd | Wholesale & retail | 2026 |
| Fiontar Group Ltd | Administrative & support | 2014 |
| Fire Door & Screens Compliance Solutions Ltd | Construction | 2020 |
| Fire Fighting Engineering LP | | 2018 |
| Fire Guide Ltd | Public administration | 2025 |
| Fire Pisces Limited | Real estate | 2021 |
| Fire Risk N.I. Limited | Professional & scientific | 2013 |
| Fire Safety Solutions (Northern Ireland) Ltd | Public administration | 2009 |
| Fire Security 24 Ltd | Administrative & support | 2021 |
| Fire Sprinkler Specialists Ltd | Construction | 2024 |
| Firebird Systems and Software Ltd. | Professional & scientific | 2016 |
| Firecheck Mechanical N.I. Ltd | Professional & scientific | 2013 |
| Firedance Entertainment Limited | Hospitality | 2001 |
| Firefly Group Holdings Limited | Financial services | 2020 |
| Firefly Orthoses (N.I.) Limited | Manufacturing | 2020 |
| Firellano Ltd | Wholesale & retail | 2023 |
| Firesafe Protection Systems Ltd | Construction | 2011 |
| Fireside Loans Limited | Financial services | 2012 |
| Firestone Belfast Limited | Hospitality | 2021 |
| Firewood Ireland Ltd | Agriculture & fishing | 2018 |
| Firlands Properties Limited | Households | 2008 |
| Firmorian Film Productions Limited | Information & communication | 2018 |
| First AID Course Belfast Ltd | Education | 2026 |
| First Class Blinds Belfast Ltd | Other services | 2017 |
| First Class Solar Ltd | Construction | 2022 |
| First Delta Technologies Limited | Real estate | 2014 |
| First Light Promotions Ireland Ltd | Wholesale & retail | 2024 |
| First Medic Events Ltd | Health & social care | 2018 |
| First Office Management Services Limited | Administrative & support | 2026 |
| First Press Records Limited | Wholesale & retail | 2023 |
| First Take Safety Ltd | Public administration | 2020 |
| First Time Buyer Mortgages Ltd | Financial services | 2025 |
| Firstsource Property and Facility Management Ltd | Real estate | 2024 |
| Firview Ltd | Hospitality | 2024 |
| Fiscal Accounts Ltd | Professional & scientific | 2018 |
| Fischer Pharmaceuticals Ltd | Wholesale & retail | 2025 |
| Fish and Chicken House Ltd | Hospitality | 2026 |
| Fish Peach Limited | Wholesale & retail | 2023 |
| Fit Factory (Larne) Limited | Arts & recreation | 2016 |
| Fit for Life Physiotherapy Ltd | Health & social care | 2019 |
| Fit House Belfast Ltd | Arts & recreation | 2022 |
| Fitch Co 4 NI Ltd | Extraterritorial | 2025 |
| Fitch Co 7 NI Ltd | Extraterritorial | 2025 |
| Fitch Co 8 NI Ltd | Extraterritorial | 2025 |
| Fitmiss Ltd | Arts & recreation | 2025 |
| Fitness Academy Belfast Ltd | Arts & recreation | 2025 |