Sea snail

common name for snails that normally live in saltwater

Sea snail is a common term for gastropods which live in the sea (marine gastropods). It is not a formal term, just a term in common use.

Live sea snail, species Nataea, photographed in situ
A species of sea snail in its natural habitat: two individuals of the wentletrap
Charonia, the shell of a sea snail called Triton's trumpet