Sargassum nudibranch 
Sarika resplendens 
Sclerodoris apiculata 
Sclerodoris tuberculata 
Scorpion Spider Conch 
Scyllaea fulva 
Sea Lemon 
Semicassis labiata 
Semicassis undulata 
Semper's Armina 
Sepia elegans 
Seven-armed octopus 
Shag-rug Nudibranch 
Shagreen 
Shireen's Phyllidiopsis 
Short-tailed ceratosoma 
Sky Blue Phyllidia 
Slender Roboastra 
Slug-like cowry 
Small Giant Clam 
Small Pointed Snail 
Smaragdia souverbiana 
Smooth Giant Clam 
Smooth Periwinkle