Filodrillia tricarinata is a species of sea snail, a marine gastropod mollusk in the family Borsoniidae.

This is a banded shell without plaits, which is unusual in the genus, but it has three delicate keels, one of which is on the suture, and the spaces between are shallow concave grooves.

The sinus is entirely posterior, is wide and deep, and the outer lip is thickened.

broad, with four spirals in each whorl, and with 16 oblique axial lirae like those in the previous form ; or it may be a shell of 10 mm.

Several of these might be regarded as distinct species did not intermediate forms reveal a complete gradation between them.