The tiny South Pacific island states of Samoa and Kiribati were the first countries to welcome in the new year.
Fireworks burst over Samoa'a capital, Apia, where tourists mingled with islanders to ring in 2020.
Samoa, which has a population of 200,000, moved to New Year's Eve pole position in 2011 when it decided to redraw the international dateline.
Its westward jump across the dateline means it is now among the first inhabited places on Earth to greet the new year. The decision was taken in order to align the country's time with its major trading partners in the region.
American Samoa, located about 125 kilometres east, will be among the last to show 2019 - and the decade - the door.
