Cystiscus havannensis is a species of very small sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae.
The size of the shell attains 1.73 mm. Shell is minute, hyaline, thin, translucent white, glossy and smooth. It has a low, rounded spire with 2 whorls tapering to the base. Its head and tentacles are opaque orange.
This marine species occurs off Vanuatu in very shallow, muddy pass with algae growth on the dead coral.