Samoa and Tokelau have skipped a day - and jumped westwards across the international dateline - to align with trade partners.
As the clock struck midnight (10:00 GMT Friday) as 29 December ended, Samoa and Tokelau fast-forwarded to 31 December, missing out on 30 December entirely.
Samoa announced the decision in May in a bid to improve ties with major trade partners Australia and New Zealand.
Neighbouring Tokelau decided to follow suit in October.
The change comes 119 years after Samoa moved in the opposite direction. Then, it transferred to the same side of the international date line as the United States, in an effort to aid trade.
But New Zealand and Australia have become increasingly valuable trade partners for the country.
Speaking from Samoa shortly after the change, at midnight local time, journalist Rico Tupai said the town was alive.
"You can hear the sound of a lot of vehicles going round town, going round the town centre clock and tooting their horns. People screaming," he said.
"We have once again achieved another milestone in our history of Samoa."
Samoan Prime Minister Tuila'epa Sailele Malielegaoi said he expected to see immediate benefits from the change, particularly for the tourist industry, as Samoans would now have five working days of continuous contact with counterparts in New Zealand and Australia.
"While it's Friday here, it's Saturday in New Zealand, and when we're at church on Sunday, they're already conducting business in Sydney and Brisbane," the prime minister said in the countdown to the switch.
Mr Malielegaoi later said he had just attended a ceremony to signal the change in time zone which was followed by morning tea and coffee for the people who had attended to "applaud the occasion".
He added that the change would have particular benefits for Samoans needing to travel to New Zealand to attend to family business.
Samoa is located approximately halfway between New Zealand and Hawaii and has a population of 180,000 people. Around 131,000 people living in New Zealand are of Samoan descent, according to New Zealand's 2006 census.
Local time up to 29 December had been 23 hours behind Auckland - but now it is one hour ahead.
Tokelau is a tiny New Zealand-administered territory of three islands. It lies to the north of Fiji, approximately half-way between Hawaii and the Australian coast.