Kiribati is associated with the world's first inhabited-place New Year's celebrations because of its UTC+14 time zone.
Kiribati's Line Islands, including Kiritimati, use Line Islands Time, which is UTC+14. This places them at the earliest civil time zone on Earth, so midnight arrives there before it arrives in places farther west. As a result, Kiritimati is commonly described in media as one of the first inhabited places to enter a new year.
The country shifted the International Date Line around its eastern islands in 1994, bringing the nation onto the same calendar date. The change removed a large date difference between the Gilbert, Phoenix, and Line island groups.
The phrase “first country” can be misleading because time-zone boundaries and inhabited locations are the real issue. Fiji, Samoa, and Tonga are also early Pacific celebrants, but they do not use Kiribati's UTC+14 Line Islands time.