Amphithalamus vallei is a species of minute sea snails, marine gastropod mollusks or micromollusks in the family Anabathridae.
The length of the shell varies between 1.07 mm and 1.25 mm, its diameter between 0.67 mm and 0.87 mm.
This species occurs in the Caribbean Sea off Cuba, Bonaire, Sint Eustatius and Saba and Puerto Rico.