Kiritimati or Christmas Island is a Pacific Ocean raised coral atoll in the northern Line Islands, and part of the Republic of Kiribati.

The island has the greatest land area of any coral atoll in the world: about 322 square kilometres (124 sq mi); its lagoon is about the same size. The atoll is about 150 km (93 mi) in perimeter, while the lagoon shoreline extends for over 48 km (30 mi). Christmas Island comprises over 70% of the total land area of Kiribati, a country encompassing 33 Pacific atolls and islands.

Kiritimati Island (Christmas) is well known for its world class bone fishing. It also has excellent birdwatching and surfing opportunities.

It lies 232 km (144 mi) north of the Equator, 6,700 km (4,200 mi) from Sydney, and 5,360 km (3,330 mi) from San Francisco. Christmas Island is in the world's farthest forward time zone, UTC+14, and Christmas Island is one of the first inhabited places on Earth to experience the New Year each year (see also Caroline Atoll, Kiribati). Despite being 2,460 km (1,530 mi) east of the 180 meridian, a 1995 realignment of the International Dateline by the Republic of Kiribati "moved" Christmas Island to west of the dateline.