| Seroba Life Sciences | |
| Serosep Ltd | |
| Share IT | |
| Shareline | |
| Shercom Ltd | Carlow County Council |
| Shiny Frog | Dublin City Council |
| Shopbox AI Ltd | |
| Shopism | |
| Sidero Ltd | |
| Sigma-X Ltd | Galway City Council |
| Sigmar Recruitment | |
| Signum Surgical | |
| Signum Surgical | |
| Silicon Republic | Dublin City Council |
| Silicotec Europe | Galway City Council |
| Silmaril Consultants | Cork City Council |
| Silverarm Solutions Ltd | Dublin City Council |
| Simply Zest Ltd | Dublin City Council |
| Simtech | |
| Simuledge Ltd | Kildare County Council |
| Siren | |
| SitePassport | Dún Laoghaire-Rathdown County Council |
| SiteStream SEO | Fingal County Council |
| SK Biotek | |
| SketchUcation, LLC | Clare County Council |
| Skillnet Ireland Company Ltd | |
| Smart Dublin | |
| SmartBay | |
| SmartCloud | |
| Smartfrog Group | Dublin City Council |
| Smarttech | Dublin City Council |
| Smartweb.ie | |
| SMBC Aviation Capital | |
| SMBC Aviation Capital | |
| Smudge Design | Dublin City Council |
| Sofodata | |
| Soft-ex | Dublin City Council |
| SoftCo Group Ltd | Dún Laoghaire-Rathdown County Council |
| Softonomy | Dublin City Council |
| Softouch Technologies Ltd | Wexford County Council |
| SoftPact | Dublin City Council |
| SoftPotential Ltd | |
| Software Asset Management Ireland | Dublin City Council |
| Software Placements | |
| Softworks Ltd | Wicklow County Council |
| Soldigital Ltd | Cork City Council |
| Solgari | |
| SoloCheck | |
| Sonalake Ltd | Dún Laoghaire-Rathdown County Council |
| Sonitus Systems | |