| CR2 | |
| Craft Digital | |
| Cre8 Web Design | Dublin City Council |
| CreateSend | |
| Creative Ireland | Dublin City Council |
| CreatorSEO | |
| Credit Logic | |
| CreditExpo | |
| Creme Software Ltd | Dublin City Council |
| Critical Data Services | |
| CRM Together | Dublin City Council |
| CroíValve | |
| Cruatech | |
| Crust Technology Ltd | Cork City Council |
| CSS Animation | Dublin City Council |
| CT Solutions | |
| Cubic Telecom | Dún Laoghaire-Rathdown County Council |
| Cully Automation | |
| Curran Scientific | |
| CurrencyFair Ltd | Dublin City Council |
| CXV Global | |
| Cyan Bear | Dublin City Council |
| Cyberdrone | |
| Cylon Controls Ltd | Dublin City Council |
| D4H Technologies Ltd | Dublin City Council |
| Daft Media Ltd | Dublin City Council |
| DamsonCloud | |
| Daretech | |
| Data Fusion International | Dublin City Council |
| Data Ireland | |
| Data Protection Commission | |
| Data Protection Commissioner | Dublin City Council |
| Data Rescue | |
| Data Works | |
| Dataduct Technologies Ltd | Dún Laoghaire-Rathdown County Council |
| Datalex | Dublin City Council |
| DataRecovery | South Dublin County Council |
| DataRep | |
| Dataships | |
| DataSolutions Ltd | Dublin City Council |
| Datatrust | South Dublin County Council |
| DataTrust Ltd | Dublin City Council |
| Dataworks Ltd | Waterford City and County Council |
| DB Alliance Ltd | Cork County Council |
| DCB Group Ltd | Wicklow County Council |
| DCU Ryan Academy | Dublin City Council |
| DecaWave | Dublin City Council |
| Deciphex | |
| DeJAY Royale | South Dublin County Council |
| Delmec Engineering Ltd | Carlow County Council |