A slender tern with a short bill. Breeding adults are dark-capped with an ashy-gray body, a strongly contrasting white cheek stripe and rump, and a reddish bill and legs. In flight, underwings and uppertail are mostly grayish. In non-breeding plumage resembles other non-breeding terns, but note structure. Restricted to a handful of subantarctic islands, where it forages in inshore waters; common on Kerguelen and uncommon on Crozet and Marion. In breeding plumage, the larger Antarctic Tern is paler gray than Kerguelen, with a larger bill and whitish (not grayish) uppertail and underwings. Arctic Terns (in non-breeding plumage) only overlap with Kerguelen Terns (in breeding plumage) in austral summer.