Occasional spells of rain failed to dampen the spirits of revellers gathering in central London for a vibrant midnight show featuring about 12,000 fireworks - and producing 50,000 projectiles.
As in previous years, the London Eye was the focal point of the pyrotechnic extravaganza, which could be seen for miles around.
Performers led the crowds in a lively, rock-inspired rendition of Auld Lang Syne as the fireworks came to an end.
Tickets for London's ceremony, organised by the Mayor, were sold out - with partygoers shuffling past security barriers in hope of a great view along the South Bank.
But it has been business as usual for the Metropolitan Police, with 3,000 officers patrolling the city centre.
Officers have stressed they have no specific intelligence to suggest London's event will be the target of a terrorist incident.
Superintendent Jo Edwards said she wanted the 100,000 attendees "to be reassured, not frightened by the number of police officers they see".
Meanwhile, police in the German city of Munich have urged revellers there to avoid large crowds after they received "serious information there will be an attack tonight".
In Edinburgh, an all-Scottish line up of bands and musicians helped 75,000 Hogmanay attendees celebrate the end of 2016 in style - with Biffy Clyro among the performers.
The world-famous event boasted four stages for visitors, who travelled from more than 80 countries to join in the festivities.
Just before midnight, a message from British astronaut Tim Peake was beamed onto screens around Edinburgh, which was recorded at the International Space Station.
In the video, he showed off his back-flipping skills and said: "Hello UK and welcome on board the ISS. Up here we work on Greenwich Mean Time, which means we will be celebrating at the same time as everybody else in the UK.
"I would like to wish everybody on our beautiful planet earth a very fun New Year's Eve and happy, healthy 2016."
David Cameron and Jeremy Corbyn have also released their New Year messages to the public, with the Prime Minister saying this will be the year when Britain makes "significant strides" towards prosperity, safety and security.