| Federation of Family Practices Craigavon C.I.C. | Health & social care | 2015 |
| Federation of Family Practices Newry and District C.I.C. | Health & social care | 2015 |
| Fedora Limited | Real estate | 2013 |
| FEE Enterprises LP | | 2018 |
| Feenan & Co Ltd | Real estate | 2024 |
| Feeney Diagnostics Limited | Health & social care | 2011 |
| Feeney Print Ltd | Administrative & support | 2011 |
| Feet First Podiatry (Newry) Ltd | Health & social care | 2023 |
| Fegan Construction Ltd | Construction | 2015 |
| Fegan Flooring Ltd | Construction | 2017 |
| Fegan Hardware Ltd | Wholesale & retail | 2026 |
| Fegan Motor Factors Limited | Wholesale & retail | 2006 |
| Fegan Plant Sales Limited | Wholesale & retail | 2021 |
| Feileacan Properties Limited | Real estate | 2025 |
| Feisaction Ltd | Arts & recreation | 2025 |
| Felix O'Hare & Company Limited | Construction | 1944 |
| Fermanagh Rope & Plastic Limited | Agriculture & fishing | 1997 |
| Fernbank Construction Limited | Construction | 2014 |
| Fernhill Consulting Ltd | Administrative & support | 2026 |
| Ferris Agencies Limited | Wholesale & retail | 2020 |
| Ferryhill Events Limited | Professional & scientific | 2019 |
| Ferryhill Hospitality Ltd | Hospitality | 2024 |
| Ferville Limited | Construction | 2005 |
| Fews View Ltd | Construction | 2026 |
| FG Fegan & Co Limited | Construction | 2013 |
| FGM Plumbing & Heating Ltd | Construction | 2019 |
| FH Contracts Ltd | Construction | 2018 |
| FH Legal Services Limited | Administrative & support | 2024 |
| Ficalo Limited | Health & social care | 2017 |
| Fiebig Wolfgang Ltd | Wholesale & retail | 2023 |
| Fieldmotion Ltd | Information & communication | 2012 |
| FIN and Flame Ltd | Hospitality | 2026 |
| Fin-Ray Limited | Wholesale & retail | 1997 |
| Financial Facility Partners Limited | Extraterritorial | 2015 |
| Finbotics Limited | Information & communication | 2025 |
| Finca Skin Organics Limited | Manufacturing | 2018 |
| Finding Solas CIC | Health & social care | 2025 |
| Finectra Limited | Information & communication | 2025 |
| Finefield Projects L.P. | | 2017 |
| Finegold Trade L.P. | | 2015 |
| Finepoint Contracts Limited | Construction | 2009 |
| Finepoint Homes Limited | Construction | 2004 |
| FINEST.DETAIL2 Ltd | Administrative & support | 2025 |
| Finn Bidco UK Limited | Financial services | 2024 |
| Finnegan Contracts Ltd | Construction | 2013 |
| Finneys Pram Ltd | Wholesale & retail | 2021 |
| Finowen Limited | Hospitality | 1997 |
| Finrealgroup LP | | 2021 |
| Finseta Payment Solutions Limited | Other services | 2010 |
| Fintan Doyle | Health & social care | 2016 |
| Fintone Nursery Limited | Wholesale & retail | 2013 |
| Fire Plus Ltd | Public administration | 2024 |
| Fire Smoke Food Catering Ltd | Hospitality | 2025 |
| Firegold Nordic L.P. | | 2017 |
| Firewok Annalong Ltd | Hospitality | 2025 |
| Firlea Management Services Limited | Households | 2001 |
| First Choice OIL Ltd | Wholesale & retail | 2009 |
| First Derivative Ltd | Information & communication | 2022 |
| First Go Wholesale Ltd | Wholesale & retail | 2017 |
| First Impressions Photography Ltd | Professional & scientific | 2018 |
| First Steps Day Care Nursery (Kilkeel) Ltd | Health & social care | 2023 |
| First Steps Day Care Nursery Ltd. | Health & social care | 2015 |
| First Watch Offshore Solutions Limited | Transport & logistics | 2014 |
| Fisher & Fisher Solicitors Limited | Financial services | 2011 |
| Fisher Mullan Solicitors Limited | Professional & scientific | 2012 |
| Fishtrapr Ltd | Wholesale & retail | 2026 |
| Fit Club Newry C.I.C. | Other services | 2015 |
| Fitz Tranz International Ltd | Transport & logistics | 2024 |
| Fitzbrick Construction NI Limited | Construction | 2024 |
| Fitzmaurice Construction Limited | Construction | 2016 |
| Fitzpatrick & Kearney Limited | Professional & scientific | 2007 |
| Fitzpatrick Energy Limited | Energy | 2014 |
| Fitzpatrick Systems Limited | Professional & scientific | 1977 |
| Fitzpower Ltd | Wholesale & retail | 2025 |
| Fitzsimons Mallon Limited | Professional & scientific | 2012 |
| Fitztranz Ltd | Transport & logistics | 2020 |
| Fivelights Ltd | Information & communication | 2019 |
| Fiveways Healthcare Limited | Wholesale & retail | 2010 |
| FK Medical Rooms Ltd | Health & social care | 2021 |
| FL Take-Away Limited | Hospitality | 2019 |
| Flagstaff Building Services Ltd | Administrative & support | 2009 |
| Flagstaff Farm & Hardware Supplies Ltd | Wholesale & retail | 2001 |
| Flagstaff Holding Limited | Other services | 2012 |
| Flagstaff Lodge Ltd | Extraterritorial | 2025 |
| Flagstaff Logistics N.I. Limited | Other services | 2012 |
| Flagstaff Management Company Limited | Households | 2003 |
| Flagstaff Shaving Limited | Wholesale & retail | 2019 |
| Flash Enterprises Limited | Administrative & support | 2024 |
| Fleet Plan Hire NI Ltd | Wholesale & retail | 2026 |
| Fleming Metal Recycling Ltd | Manufacturing | 2009 |
| Fleming Precision Engineering Limited | Manufacturing | 2024 |
| Flickernet Ltd | Information & communication | 1999 |
| Floortherm Renewables Limited | Construction | 2013 |
| FLORIN21 Limited | Information & communication | 2023 |
| Flosure Limited | Information & communication | 2011 |
| Flynn Entertainment Limited | Information & communication | 2016 |
| Fmck Consultancy Ltd | Professional & scientific | 2025 |
| FMD Carpentry Ltd | Construction | 2018 |
| FMN Clinical Research Services Ltd | Professional & scientific | 2012 |
| FMOC.777 Ltd | Professional & scientific | 2019 |