Kiribati is among the first places to welcome New Year's Day because part of the country uses UTC+14.
The relevant location is Kiritimati, also called Christmas Island, in Kiribati's Line Islands. Its civil time is Line Islands Time, which is UTC+14, the world's furthest-ahead standard time zone. As a result, midnight arrives there before it does in places farther west.
Kiribati moved the International Date Line eastward around its islands in 1994. Before that change, the country's islands were divided by the date line, making it difficult for the nation to share the same calendar day. The adjustment placed the Line Islands on the same side of the date line as the rest of Kiribati.
Being among the first to reach January 1 does not mean every part of Kiribati experiences midnight simultaneously: the country spans several time zones. Kiritimati is the best-known location connected with the early New Year transition.