Trinchesia pinnifera is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Trinchesiidae.
This species was described from Sagami Bay, Japan. It was subsequently reported from Kii Peninsula, Osaka Bay, Toyama Bay and Tsuruga Bay.
This Trinchesia is a white animal with a single, broken, band of orange-yellow below the tip of the cerata.