Trinchesia foliata is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusk in the family Trinchesiidae.

It has been reported from the NE Atlantic, from the Faeroes and Norway south to Portugal, and in the Mediterranean Sea.

[3] The typical adult size of this species is 8–11 mm.

[4] Trinchesia foliata feeds on hydroids.

It has been reported from a number of hydroids including Dynamena pumila, Sertularella gayi, Sertularella polyzonias and Abietinaria abietina family Sertulariidae.