Which Kiribati atoll has the largest land area among atolls containing a lagoon? Kiritimati is the answer.
Also called Christmas Island, Kiritimati lies in Kiribati's northern Line Islands. It has about 312 square kilometres of land surrounding a large, partly enclosed lagoon system. That makes it the world's largest atoll by land area when the comparison is limited to atolls that actually contain a lagoon.
The wording matters because some sources loosely call Kiritimati the world's largest atoll overall. Raised coral islands such as Lifou and Rennell can have greater land area, but they lack lagoons and are therefore excluded by this definition. Kiritimati's land and lagoon boundaries are also irregular, with tidal flats, salt ponds and partially dried lagoon sections.
The Gilbert atolls listed as alternatives are much smaller by land area. Kiritimati is famous for its remote setting, bonefish fisheries and unusual time-zone status: at UTC+14, it is among the first inhabited places to enter a new calendar day. Its name is the Gilbertese rendering of “Christmas.”