| Fleville Bros Ltd | Administrative & support | 2012 |
| Flex Communications Limited | Information & communication | 2025 |
| Flex Language Services Ltd | Professional & scientific | 2011 |
| Flexaero Ltd | Arts & recreation | 2004 |
| Flexera Reformers Ltd | Wholesale & retail | 2025 |
| Flexform Ltd | Administrative & support | 1996 |
| Flexgymni Ltd | Arts & recreation | 2024 |
| Flexi Lets Belfast Ltd | Real estate | 2021 |
| Flexible Property Services Ltd | Real estate | 2022 |
| Flexibus Limited | Extraterritorial | 1966 |
| Flexio Ltd | Information & communication | 2025 |
| Flexport Projects L.P. | | 2017 |
| Flint Studios Ltd | Information & communication | 2011 |
| Flipside Opinions Ltd | Professional & scientific | 2021 |
| FLK Medical Ltd | Health & social care | 2026 |
| FLO Autos Ltd | Wholesale & retail | 2025 |
| Flocare Cleaning Services Ltd | Administrative & support | 2025 |
| Flockevents Ltd | Administrative & support | 2010 |
| Flogas Natural GAS Ltd | Energy | 2014 |
| Floodlight Pictures Ltd | Information & communication | 2020 |
| Floor Fit NI Ltd | Construction | 2018 |
| Flooring Solutions (NI) Ltd | Construction | 2012 |
| Flooringxtra Ltd | Construction | 2026 |
| Flora Beauty Life Ltd | Wholesale & retail | 2026 |
| Floral Magicians Ltd | Wholesale & retail | 2026 |
| Floral Management Limited | Real estate | 2007 |
| Floralearth Design Ltd | Wholesale & retail | 2019 |
| Floralearth Limited | Wholesale & retail | 2012 |
| Flore Fariya Ltd | Wholesale & retail | 2025 |
| Florence Brennan Restaurants Ltd | Hospitality | 2020 |
| Florencecourt Limited | Financial services | 2022 |
| Floresta Limited | Extraterritorial | 2007 |
| Florina FLO Ltd | Health & social care | 2022 |
| Floritz Limited | Real estate | 2026 |
| Flour Power Catering Ltd | Hospitality | 2012 |
| Flourish (NI) Limited | Health & social care | 2014 |
| Flourish Interactive Limited | Information & communication | 2026 |
| Flourish Mountain Trade Ltd | Wholesale & retail | 2024 |
| FLOW4U Limited | Professional & scientific | 2024 |
| Flowerer Ltd | Wholesale & retail | 2025 |
| Flowers ARE US Limited | Wholesale & retail | 2025 |
| Flowlens Ltd | Information & communication | 2009 |
| Fluent Format Limited | Professional & scientific | 2021 |
| Fluent Technology Limited | Information & communication | 2001 |
| Fluga Engineering Ltd | Manufacturing | 2018 |
| Fluid Estates Ltd | Households | 2025 |
| Fluid Plumbing & Heating Ltd | Construction | 2016 |
| Flux Glod Ltd | Wholesale & retail | 2025 |
| FLY Atlantic Ltd | Transport & logistics | 2021 |
| FLY Fahad Ltd | Wholesale & retail | 2025 |
| FLY to the Clouds Group Ltd | Wholesale & retail | 2024 |
| Flynn & Co Professional Services Ltd | Health & social care | 2026 |
| Flynn & Mcgettrick Solicitors Limited | Professional & scientific | 2011 |
| Flynn VET Holdings Ltd | Professional & scientific | 2026 |
| Flynn Veterinary Ltd | Professional & scientific | 2007 |
| Flytech Pest Control Solutions Ltd | Professional & scientific | 2019 |
| Flytone Innovations Ltd | Wholesale & retail | 2023 |
| FM Consultancy N.I. Limited | Professional & scientific | 2023 |
| Fmac Limited | Construction | 2025 |
| Fmca Ltd | Professional & scientific | 2019 |
| Fmcc Property Ltd | Real estate | 2022 |
| Fmjxhj Limited | Wholesale & retail | 2024 |
| FMN Creations Limited | Administrative & support | 2019 |
| FMN Properties Limited | Construction | 2013 |
| FMP Construction Joint Venture Limited | Extraterritorial | 2013 |
| FMP Joint Venture Limited | Construction | 2013 |
| FNB Supplies Ltd | Wholesale & retail | 2024 |
| FNH Solutions Limited | Professional & scientific | 2004 |
| Foal Operations Limited | Information & communication | 2025 |
| Foamquip Limited | Wholesale & retail | 2009 |
| Focus Drive NI School of Motoring Ltd | Education | 2026 |
| Focus on CRM Ltd | Information & communication | 2025 |
| Focus Tuition Belfast Ltd | Education | 2017 |
| Focused Technical Limited | Wholesale & retail | 2019 |
| FOG Holdings Ltd | Real estate | 2023 |
| Fogarty Medical Ltd | Health & social care | 2022 |
| Folkdeep CIC | Education | 2025 |
| Folklore Yarns Ltd | Wholesale & retail | 2018 |
| Follies Trust - the | Education | 2006 |
| Folly Lane Properties Limited | Real estate | 2023 |
| Folly Lonan LLP | | 2023 |
| Fomo Partners Limited | Wholesale & retail | 2022 |
| Fomura Ltd | Information & communication | 2025 |
| Fonacab (Belfast) Limited | Transport & logistics | 1962 |
| Fonavalue & 7 Seater Taxi Ltd | Transport & logistics | 2020 |
| Fondation Jean Carlier Development Ltd. | Hospitality | 2014 |
| Fone Booth Ltd | Wholesale & retail | 2015 |
| Fone Boutique Ltd | Other services | 2016 |
| Fone Solution Repair Centre Ltd | Wholesale & retail | 2020 |
| Fone Zone Solutions Limited | Wholesale & retail | 2021 |
| Fonenova Ltd | Wholesale & retail | 2026 |
| Fonezone Telecommunications Limited | Agriculture & fishing | 2001 |
| Fontaine Place Management Company Limited | Extraterritorial | 2004 |
| Food and Drink Sector Skills | Administrative & support | 1991 |
| Food Equipment Services (N.I.) Ltd | Manufacturing | 2011 |
| Food NI Ltd | Hospitality | 2009 |
| Food Technology Services (NI) Ltd | Manufacturing | 2006 |
| Food to Go Awards Ltd | Hospitality | 2024 |
| Food Waste 4 Autism C.I.C. | Water & waste | 2018 |
| Foodhubni Limited | Hospitality | 2026 |