Those in the South Pacific officially welcomed the new decade as it hitS 4pm in Bangladesh.
Situated immediately west of the International Date Line in the Pacific Ocean, Kiritimati or Christmas Island and Samoa have started the ball rolling for New Year's revellers across the globe, reports the Metro.
Kiribati, an island nation in the pacific, contains 3,200 coral atolls strewn across more than three million square miles, straddling the equator.
The island nation finds itself on the front line of the battle against climate change, facing drought and rising sea levels as the new year begins.
In 2020, a project funded by the World Bank, Asian Development Bank, Green Climate Fund and Kiribati's government brings hope of providing safe and climate-secure drinking water to the main island of Tarawa, which is home to most of the nation's 110,000 people.
In Samoa, New Year's Eve was more sombre than usual. While fireworks erupted at midnight from Mount Vaea, overlooking the capital, Apia, the end of the year was a time of sadness and remembrance.
With the epidemic now contained, the Samoa Observer named as its Person of the Year health workers who fought the outbreak.
The newspaper wrote: 'We have experienced extreme sadness and sorrow. Since the first measles death, the pain has only deepened. But amidst much hopelessness and tears, we have also seen the best of mankind in this country's response.'
Next up it will be the turn of partygoers in New Zealand who will celebrate the start of 2020 at 5pm in Bangladesh time.
At 7pm, the clock will strike midnight across much of Australia, including Sydney, where its spectacular harbour fireworks display is going ahead despite the deadly bushfire crisis.
Pressure has been building on Australia's Prime Minister Scott Morrison to cancel the display but he has vowed to go ahead to show the world the country's resilience.
Wildfires in the past several weeks have killed 12 people and razed more than 1,000 homes, with New South Wales, Australia's most populous state, bearing the brunt.
But while the City of Sydney Council has approved tonight's fireworks, fire authorities warned they could be cancelled if catastrophic wildfire conditions were declared.
As the clock strikes 12 in London, 6am on Wednesday in Bangladesh; 12,000 fireworks - including 2,000 from the London Eye on the River Thames - will be set off to see in the New Year.
Big Ben's chimes will also be heard for the first time in a year amid renovation work to the clock tower.
Outlying American islands in the South Pacific, which are just east of the International Date Line, will be the last to welcome 2020 at midday on Wednesday UK time - more than 24 hours after Samoa.