The Solitary Sandpiper is shaped like the Greater and Lesser Yellowlegs, but is smaller than both and has shorter, greenish legs. The bill is straight, thin, and of medium length. The dark back is covered in light spots, and the head is streaked gray. The head is dark enough that the white eye-ring is fairly distinct. The tail pattern, seen in flight, is distinctive. The outer edges are white, barred with black, with a dark center. The wings are entirely dark underneath, sharply contrasting with the white belly.