Samoa moved to the west side of the International Date Line in 2011, creating a major New Year's Eve date change.
At the end of December 29, 2011, Samoa advanced its calendar by one day and moved from UTC−11 to UTC+13, effectively skipping December 30. The change placed Samoa on the same side of the date line as important trading partners such as Australia and New Zealand.
Because December 30 did not occur in Samoa that year, the country went from Thursday, December 29, directly to Saturday, December 31. Its first New Year's Eve after the change therefore followed the newly adopted calendar position, while neighboring American Samoa remained on the opposite side of the date line.
The change is sometimes described as Samoa “losing a day,” but it was a civil-time decision rather than an alteration of the Earth's rotation. Samoa had previously shifted to the eastern side of the line in 1892, when it repeated July 4.