| Cork College of FET | |
| Cork Electronics Industry Association | Cork City Council |
| Cork Insitute of Technology | Cork City Council |
| CorkBIC | |
| Corlytics | |
| Corporate Governance Institute | |
| Corteza | |
| Cosmo Pharmaceuticals N.V. | |
| Cotter Agritech | |
| CourseCo | |
| Coworking.ie | |
| CozmoTec | |
| CozmoTec | |
| CR2 | Dublin City Council |
| Craft Digital | |
| Cre8 Web Design | Dublin City Council |
| Cream Creative Ltd | |
| 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 | |
| Crop SRM | |
| Cruatech | |
| Crust Technology Ltd | Cork City Council |
| Cryt | |
| CSS Animation | Dublin City Council |
| CT Solutions | |
| Cubic Telecom | Dún Laoghaire-Rathdown County Council |
| Cully Automation | |
| Curiosity Software Ireland Ltd | |
| Curran Scientific | |
| Curran Scientific | |
| CurrencyFair Ltd | Dublin City Council |
| Customer Experience Excellence Ireland | |
| CXV Global | |
| Cyan Bear | Dublin City Council |
| Cylon Controls Ltd | Dublin City Council |
| Cyrex Ltd | |
| Cytidel | |
| D4H Technologies Ltd | Dublin City Council |
| Daft Media Ltd | Dublin City Council |
| DamsonCloud | |
| Dan Malone | |
| Daretech | |
| Data Fusion International | Dublin City Council |