| Herbst Software | Wicklow County Council |
| Heritage Ventures Ltd | |
| Hickey Communications Ltd | Cork County Council |
| Hidden Depth | Dublin City Council |
| High Spec Tech | Dún Laoghaire-Rathdown County Council |
| Hire Intelligence | Dublin City Council |
| Horseware Ireland | |
| Host & Co. | |
| Host Ireland | Dublin City Council |
| Host.ie | Fingal County Council |
| Hostelworld Services Ltd | Dún Laoghaire-Rathdown County Council |
| Hosting & Web Solutions | Kildare County Council |
| Hosting Ireland | Waterford City and County Council |
| Hostr | Dublin City Council |
| House of Design | Dublin City Council |
| HR Duo | |
| HSBC Ireland | |
| HSolutions | Limerick City and County Council |
| HST Solutions | Dublin City Council |
| Hublio | |
| Hutchison 3G Ireland Ltd | Dublin City Council |
| I.T. Alliance Group | Dublin City Council |
| IACT | Dublin City Council |
| Ibec | Dublin City Council |
| iCabbi | |
| ICCM Hosting | Wexford County Council |
| ICDL Europe | Dún Laoghaire-Rathdown County Council |
| ICON plc | |
| iCONX | South Dublin County Council |
| ID-Pal | |
| Ideabubble | Limerick City and County Council |
| Idiro Technologies | Dublin City Council |
| IE Domain Registry Ltd | Dún Laoghaire-Rathdown County Council |
| ieComputerSystems Ltd | Dublin City Council |
| ieinternet | Dún Laoghaire-Rathdown County Council |
| Ilikecake Ltd | South Dublin County Council |
| Imedia Interactive | Limerick City and County Council |
| Immedis | |
| Immersive Technologies Skillnet | |
| Impedans Ltd | |
| INET Computer Solutions Ltd | |
| Infinity IT Ltd | Dún Laoghaire-Rathdown County Council |
| Inflection Biosciences | |
| Inflight Dublin | Dublin City Council |
| Info-Maker | Dublin City Council |
| Inhousetrainning | Dublin City Council |
| Inish Technology Ventures Ltd | Dublin City Council |
| Ink & Toner Solutions Ltd | Cork City Council |
| Ink Cartriges Ireland | Dublin City Council |
| Ink Refill Depot | Limerick City and County Council |