It is a large gull with a very dark back. Females and males are identical in appearance, although with differences in size, the male being somewhat smaller. The plumage is white on the chest and grey on the back. The legs and bill bright yellow like the iris, which features a red eye ring. The young specimens have brown and dirty white tones.
It differs from Larus Michahellis (Patiamarilla Gull) by the color of the mantle, which in Larus Michahellis is grey, while in Larus Fuscus it is black.