Kiribati is among the first countries to enter the New Year because Kiritimati uses UTC+14.
Kiritimati, also called Christmas Island, is part of Kiribati's Line Islands. Its legal time is UTC+14, the world's most advanced civil time zone, so midnight arrives there before it reaches most other inhabited places. This makes the island a frequent subject of international New Year's coverage.
Kiribati moved the International Date Line around its eastern islands in 1994. The change placed the Line Islands on the same calendar day as the country's central and western island groups, helping the nation avoid having different parts of its territory on different dates. The time-zone arrangement is why Kiritimati can enter a new calendar year so early.
The phrase “first country” can be imprecise because countries may span multiple time zones and because the first locations depend on which inhabited places are being compared. Kiribati is the country most closely associated with the earliest New Year through Kiritimati and the Line Islands.