The rainbow lorikeet is a medium-sized parrot, with the length ranging from 25 to 30 cm (9.8 to 11.8 in) including the tail. The plumage of the nominate race, as with all subspecies, is very bright and colorful. The head is deep blue with a greenish-yellow nuchal collar, and the rest of the upper parts (wings, back and tail) are green. The chest is orange/yellow. The belly is deep blue, and the thighs and rump are green. In flight a yellow wing-bar contrasts clearly with the red underwing coverts. There is little to visually distinguish between the sexes. Juveniles have a black beak, which gradually brightens to orange in the adults.
Rainbow lorikeets have been introduced to Perth, Western Australia; Tasmania; Auckland, New Zealand; and Hong Kong.