Kiribati includes Kiritimati, one of the first inhabited places to celebrate New Year's Eve.
Kiritimati, also known as Christmas Island, lies in the central Pacific and uses UTC+14, the world's most advanced civil time zone. Because clocks there reach midnight before those in almost every other inhabited location, its residents are regularly among the earliest people to welcome a new calendar year.
The island is part of Kiribati's Line Islands group. In 1995, Kiribati adjusted the date-line arrangement used for its eastern islands so that the country could share the same calendar date across its territory. This change helped create the modern association between Kiritimati and being first into a new year.
“First” claims can depend on whether the question means first country, first inhabited settlement, or first location by time zone. For that reason, Kiritimati is a more precise answer than simply naming a Pacific island nation.