| Solucionex | Cáceres |
| Solusoft | Madrid |
| Solutel | Madrid |
| Solutia | Alicante |
| Solutions Copiadoras | Madrid |
| SOM Biotech | Barcelona |
| SOMOS.plus | Málaga |
| Sonicat Systems | Barcelona |
| Sortes Ingeniería Informática, S.L.U. | Madrid |
| SOS Informática Soluciones TIC Salamanca | Salamanca |
| SOS mipc | Madrid |
| Sosmatic | Barcelona |
| Sothis | Valencia |
| South Summit | |
| Soy.es | Alicante |
| Sozpic | Murcia |
| Spacecreator | Barcelona |
| Spacer Web Hosting | Cádiz |
| Spanish Proptech | Madrid |
| Spanish Startups | Madrid |
| Spanto Soft | Girona |
| SPC | Álava |
| SPIN | Barcelona |
| Spin Media, S.L. | Madrid |
| SpiraleBackup | Zaragoza |
| SpliceBio, S.L. | Barcelona |
| SpotLab | Madrid |
| Spring I/O | Barcelona |
| Spuch | A Coruña |
| Squizzo | Barcelona |
| SR Tecnologías Aplicadas | Madrid |
| SRI TEIN, S.L. | Las Palmas |
| ST Visual | Madrid |
| StageInHome | Barcelona |
| Stampery | Madrid |
| Star2Billing, S.L. | Barcelona |
| Stark Future | Madrid |
| Starshot Solutions, S.L. | Lleida |
| Start Up | Asturias |
| Startidea Málaga, S.L. | Málaga |
| Startify | Madrid |
| Startup Europe Week | Madrid |
| Startup Europe Week | Madrid |
| Startup Grind Barcelona | Barcelona |
| Startup Hub Catalonia | Barcelona |
| StartUp Labs Spain | Sevilla |
| Startup Radar Madri+d | Madrid |
| Startups' Oasis | Madrid |
| Stay App | Madrid |
| Steema Software | Girona |