The Willan’s Chromodoris (Chromodoris willani) is a tropical opisthobranch species that is a member of the nudibranch family Chromodorididae. This species can be found occurring in the warm tropical waters of the Western Pacific and has been recorded from Indonesia, Philippines, Papua New Guinea, Guam, Japan, Malaysia and Queensland in Australia. This species can be found occurring on coral reefs and looks similar to several other species that have a bluish white or translucent white background colour and dark blue or black longitudinal stripes. These other species include Chromodoris lochi, Chromodoris boucheti and Chromodoris dianae. The most distinguishing external features of Chromodoris willani are the white spots or specks on both the gills and the rhinophores. The rhinophores can range in colour from a watery translucent version of the background bluish white colour to a straw yellow-brown.
The Willan’s Chromodoris (Chromodoris willani) grows to at least 2.5cm in length.