Conus iodostoma, common name the violet-mouth cone, is a species of sea snail, a marine gastropod mollusk in the family Conidae, the cone snails and their allies. Like all species within the genus Conus, these snails are predatory and venomous. They are capable of stinging humans, therefore live ones should be handled carefully or not at all.

Description The size of an adult shell varies between 25 mm and 47 mm. The shell is thin, narrow and somewhat inflated. The spire is finely grooved. The apex is sharp. The body whorl is striate towards the base. The color of the shell is violet-white, clouded with chestnut, with revolving lines of chestnut spots.

Distribution This species occurs in the Indian Ocean off Madagascar and Mozambique.