| Freeway Developments (N I) Ltd | Real estate | 1990 |
| Freight Forwarding Services Ltd | Transport & logistics | 2025 |
| Fremantle Consulting Ltd | Information & communication | 2019 |
| Fremont ES Ltd | Administrative & support | 2019 |
| French Capital Limited | Financial services | 2022 |
| French Mills Capital Limited | Financial services | 2023 |
| French Village Bakery Ltd | Manufacturing | 2012 |
| French Village Group Ltd | Professional & scientific | 2018 |
| French Village Holdings Ltd | Professional & scientific | 2018 |
| French Village Ltd | Hospitality | 2012 |
| French Village Patisserie and Brasserie Limited | Hospitality | 2016 |
| Freqnc Limited | Information & communication | 2026 |
| Fresh 2 NI Ltd | Hospitality | 2021 |
| Fresh Bitez Ltd | Wholesale & retail | 2024 |
| Fresh Cognition Ltd | Professional & scientific | 2025 |
| Fresh Fields Cafe 1 Limited | Wholesale & retail | 2019 |
| Fresh Graphics Belfast Ltd | Manufacturing | 2008 |
| Freshco Fine Foods Ltd | Manufacturing | 2014 |
| Freshwind Digital Limited | Manufacturing | 2025 |
| Freso Ltd | Wholesale & retail | 2025 |
| Freud Todt Ltd | Wholesale & retail | 2024 |
| Frewaka Films Ltd | Information & communication | 2022 |
| Friars Wood Property Management Company Limited | Extraterritorial | 2005 |
| Friary Road Enterprises Limited | Real estate | 2000 |
| Friar’S Bush Graveyard Cemetery Ltd | Education | 2023 |
| Friends Childcare Limited | Health & social care | 2018 |
| Friends of Belfast Botanic Gardens | Other services | 2006 |
| Friends of Cliftonville Limited | Financial services | 2024 |
| Friends of Little Woods Ltd | Agriculture & fishing | 2022 |
| Friends of ST Therese Incorporating Friends of Malawi Ltd | Other services | 2000 |
| Friends of the Cancer Centre | Other services | 2013 |
| Friends of the Currie Community Ltd | Health & social care | 2026 |
| Friends of the Linen Hall Library Ltd | Other services | 2025 |
| Friendz Potier Group Ltd | Wholesale & retail | 2026 |
| Frontiers Ireland | Other services | 2000 |
| Frontline Recruitment Group Ltd | Administrative & support | 2021 |
| Frontline Research and Policy Ltd | Education | 2019 |
| Frontline Technology Services UK Limited | Information & communication | 2021 |
| Frontline Voice Ltd | Information & communication | 2025 |
| Frontstar Trade L.P. | | 2017 |
| Frostelle Ltd | Manufacturing | 2025 |
| Frozzys Ltd | Wholesale & retail | 2013 |
| Frtacn Limited | Wholesale & retail | 2024 |
| Fruit of the Vine (Belfast) Limited | Wholesale & retail | 2000 |
| Fruitatr Ltd | Wholesale & retail | 2025 |
| Fruithill Park Management Company Limited | Households | 2004 |
| Fry's Road Development Management Company Limited | Real estate | 2017 |
| Frydrych Building Limited | Construction | 2018 |
| Fryhold Limited | Financial services | 2023 |
| FS Property Holdings Ltd | Real estate | 2023 |
| Fscom Holdings Limited | Professional & scientific | 2019 |
| Fscom Limited | Professional & scientific | 2011 |
| Fsdd NI Ltd | Arts & recreation | 2021 |
| FSM Advocacy Limited | Health & social care | 2023 |
| Fsnbdn IU Ltd | Wholesale & retail | 2025 |
| FSS Property 1 Ltd | Real estate | 2025 |
| FSS Property Ltd | Real estate | 2024 |
| FSU GP Practice Management C.I.C. | Administrative & support | 2023 |
| FT Contracts (NI) Ltd | Wholesale & retail | 2014 |
| FTB Enterprises Ltd | Real estate | 2025 |
| FTB Holdings Ltd | Construction | 2026 |
| FTG Heating Limited | Construction | 2019 |
| FTM Consulting Limited | Professional & scientific | 2018 |
| FTM Worldwide L.P. | | 2018 |
| FTS Security Limited | Administrative & support | 2023 |
| Ftsie LP | | 2008 |
| FTV Properties Ltd | Administrative & support | 2023 |
| Fudesign Limited | Professional & scientific | 2023 |
| Fuel 24/7 Limited | Wholesale & retail | 2012 |
| Fuel Management Solutions Limited | Administrative & support | 2008 |
| Fuel POD Systems Ltd | Mining & quarrying | 2012 |
| Fuelcom Ireland Ltd | Manufacturing | 2022 |
| Fuelcom Ltd | Manufacturing | 2009 |
| Fugitive Pictures Limited | Information & communication | 2009 |
| Fujitsu Services Limited | | 1949 |
| Fulay Limited | Wholesale & retail | 2024 |
| Fulford - Hyman Limited | | 1996 |
| Full Circle Business Consultancy Services Ltd | Information & communication | 2018 |
| Full Circle Data Limited | Wholesale & retail | 2023 |
| Full Circle Generation Ltd | Water & waste | 2014 |
| Full Circle Management Solutions Limited | Professional & scientific | 2010 |
| Full Circle Martial Arts CIC | Education | 2025 |
| Full Potential Management Solutions Limited | Professional & scientific | 2016 |
| Fulland Limited | Wholesale & retail | 2024 |
| Fullarmoon Limited | Real estate | 2007 |
| Fullarton Healthcare Ltd | Wholesale & retail | 2023 |
| Fuller Group Ltd | Real estate | 2023 |
| Fuller Vending Ltd | Wholesale & retail | 2025 |
| Fullmart Limited | Wholesale & retail | 2024 |
| Fullwell International Limited | Wholesale & retail | 2023 |
| Fully Charged Electrical Ltd | Construction | 2020 |
| Fulton Consulting Limited | Professional & scientific | 2022 |
| Fumssion Limited | Information & communication | 2025 |
| Funcrafters Ltd | Wholesale & retail | 2025 |
| Functional Hustle Limited | Other services | 2022 |
| Fundready Ltd | Professional & scientific | 2020 |
| Funeral & Mortuary Services Limited | Other services | 2008 |
| Funereal Soft Furnishings Ltd | Other services | 2001 |
| Funkey Sports Limited | Arts & recreation | 2020 |
| Funkier Than Funk Ltd | Extraterritorial | 2009 |