Critically endangered
10 species| Photo | English | සිංහල | தமிழ் | Scientific name | IUCN | Endemic |
|---|---|---|---|---|---|---|
| Samanala Round-Eyed Gecko | — | — | Cnemaspis samanalensis | CR | — | |
| Samarakoon’s Shrub Frog | — | — | Pseudophilautus samarakoon | CR | Endemic | |
| Scalloped Hammerhead | — | — | Sphyrna lewini | CR | — | |
| Schistura scripta | — | — | Schistura scripta | CR | — | |
| Sinharaja Shrub Frog | — | — | Pseudophilautus simba | CR | Endemic | |
| Spinetail Devil Ray | — | பேய் மீன் | Mobula mobular | CR | — | |
| Sri Lanka Cruiser | — | — | Macromia zeylanica | CR | Endemic | |
| Sri Lanka Rough-Sided Snake | — | — | Aspidura deraniyagalae | CR | Endemic | |
| Stripenose Guitarfish | — | — | Acroteriobatus variegatus | CR | — | |
| Stuart’s Shrub Frog | — | — | Pseudophilautus stuarti | CR | Endemic |
