This is a large tern, second only to Caspian Tern but is unlikely to be confused with that carrot-billed giant, which has extensive dark under wing patches. Royal Tern has a long yellow bill, pale grey upperparts and white underparts. Its legs are black. In winter, the black cap becomes patchy. Juvenile Royal Terns have a scaly-backed appearance. The call is a characteristic loud grating noise like a Sandwich Tern.