| SCM Technologies Co., Ltd | Bangkok |
| ScreenToaster | |
| SCT Systems Co., Ltd | Bangkok |
| Search Engine Optimization Co., Ltd | Bangkok |
| SEG IT Services | Bangkok |
| Sellsuki Co., Ltd | Bangkok |
| Senior Com Co., Ltd | Bangkok |
| SEO Bangkok | |
| SEO Heroes Bangkok Co., Ltd | |
| SEO Thailand | |
| Servebase Communication Co., Ltd | Bangkok |
| ServerToday | Bangkok |
| Shiftleft Co., Ltd | |
| Shinawatra University | |
| Shini Software Solution | |
| Shop4Thai.com | Bangkok |
| ShopeePay | Bangkok |
| Shopstack Co., Ltd | Bangkok |
| Siam Communications | Bangkok |
| Siam Inbound Digital Marketing Agency | |
| Siam Integrated Technology Co., Ltd | Bangkok |
| Siam Network & Computer Co., Ltd | Bangkok |
| Siam Technology College | |
| Siam University | |
| Siam2Design Co., Ltd | Bangkok |
| SiamDNS | Bangkok |
| SiamLiveHost | Bangkok |
| SiamNIC | Bangkok |
| SiamSupport | Bangkok |
| Siamwebhost | Bangkok |
| SiamWebSolution | Bangkok |
| Silpakorn University | |
| Simahost4u | Bangkok |
| Simat Technologies Public Co., Ltd | Bangkok |
| Simple Different Co., Ltd | Chiang Mai |
| Sinwattana | Bangkok |
| Sisaket Rajabhat University | |
| Sitem | Bangkok |
| Sknetcenter.tht.in | Bangkok |
| Skywave Solutions (Thailand) Co., Ltd | |
| Smart Business Solutions Co., Ltd | Bangkok |
| Smart Shift Solutions | Bangkok |
| SmartSoftAsia Co., Ltd | Bangkok |
| SmileHost.Asia | Bangkok |
| SmilePHP | Bangkok |
| SML Soft | Bangkok |
| Snow Digital Co., Ltd | |
| Softmarts.com Co., Ltd | Bangkok |
| Softnet Application Co., Ltd | Bangkok |
| Softnix Tech | Bangkok |