| Frontier Technology | |
| Frontline Consultancy | Cheshire |
| Frontline Networks Ltd | West Sussex |
| Frontline Utilities Ltd | |
| Frontmedia Studio Ltd | Essex |
| FrontRow Global Ltd | |
| Frost Creative Ltd | |
| Frost Digital Design Ltd | Cambridgeshire |
| Frost Money Ltd | |
| FrostConsulting | |
| FruitCast | |
| Fruitful Studio Ltd | |
| Fruition Systems Ltd | Hampshire |
| FSCom Ltd | |
| FSE Online Ltd | Essex |
| FSI (FM Solutions) Ltd | Essex |
| Fsquared Ltd | |
| FT Technologies Ltd | Surrey |
| FTB Fund | |
| FTDI Chip | Glasgow |
| Fuel | Devon |
| Fuel Ventures | Greater London |
| Fuel3D Technologies Ltd | |
| Fulcrum Data Forensics Ltd | |
| Fulfilmentcrowd | Lancashire |
| Full Clarity | |
| Full Control Networks | |
| Full Fabric | |
| Full Metal Software | |
| Full Revolution | |
| Full Sphere Ltd | |
| Full Stack Consulting | Berkshire |
| FullCircl Ltd | |
| FullScore | |
| Fully Charged Show | Bristol |
| Funasset Ltd | Somerset |
| Function & Form | |
| Function Interactive Ltd | |
| Function28 Ltd | Devon |
| fundamental XR | |
| Fundamentally Games Ltd | |
| FundApps Ltd | |
| Funding Options Ltd | |
| Funding Xchange | |
| Fundpath Ltd | |
| Fundsquare | |
| Funel | |
| FunFair Ventures | |
| Funzing | |
| Fuolornis Systems Ltd | Newport |