This gull is large, measuring 19.7-23.2 inches (50-59 centimeters) in length, 31.8-42.3 ounces (900-1200 grams) in weight, and a wingspan of 47.2-56.3 inches (120-143 centimeters).
The head and underparts are white, with a silvery gray back.
Their wingtips are medium gray with white spots near tip and the legs are pinkish.
Juveniles have light grayish brown head and body, back, tail, and wings. Flight feathers on wing same color as back. They have a black bill and dark eyes. Legs dark gray with pink overtones.
In first Winter (Basic I) plumage, they appear similar to juveniles, but the head, throat, and breast are lighter and more streaked. The bill black and the eyes are dark brown.
In first Summer (Alternate I) plumage, the head, neck, and especially the throat whiter, but still streaked. The wing feathers worn and paler. There is a mix of clean gray and mottled feathers on back. The bill and eyes are dark.
Second Winter (Basic II) plumage features a whiter head, but the neck heavily streaked. The gull's back is mottled brownish and light gray. The underparts are white and the wing tips and tail light gray, similar to the back. Its bill has pale flesh at base, then changes to black. Their eyes are dark brown and the legs dirty pink.
Second Summer (Alternate II) plumage features a largely white with conspicuous streaking head and neck. Its back may be entirely light gray with a few brownish feathers and the underparts are mostly white. The bill yellowish at base, then black with white tip. Its eyes are dark brown.
In Third Winter (Basic III) plumage, some dirty brown feathers still remain on the otherwise white neck and head. The back is light gray with only a few dull brownish feathers and the underparts are white. Their tails are largely white with some dark smudging. Outer wing feathers (primaries) are darker gray with white tips. Inner wing feathers (secondaries) are light gray with broad white tips. The bill is yellowish at base, then black with white tip. The eyes are brown and the legs dirty pink.
In Third Summer (Alternate III) plumage, the head and neck are pure white or with only little streaking. The back is completely gray and the underparts are white. The tail is white with some dark smudging. Their bill is yellow with some red on lower mandible and the eyes are brown.