The body is translucent white with a pinkish hue over the head and tentacles. There is often a large white patch between the rhinophore bases. The cerata also have white patches and a whitish tip. The oral tentacles are very long and mobile, the rhinophores are smooth.
Facelina bostoniensis is similar, but the annulate rhinophores of Facelina bostoniensis distinguish it from Facelina dubia.
Tubularia larynx feeding on hydroids (Tubularia larynx).