All over the world people are sharing gifts, scoffing mince pies and waiting for Elf to come on TV.
But whether you're half a day behind the UK, or several hours in front, spare a thought for those keeping the country ticking over on 25 December.
Adam Spencer is one of the rangers clocking in bright and early at the Yorkshire Wildlife Park, near Doncaster.
He's keeping an eye on the carnivores at the 100-acre site, which is home to more than 300 animals including polar bears, lions, tigers and leopards.
Adam, who has worked at the park for three years, said he's one of about 10 people working today.
He stopped to take a selfie with his colleague Colin and brown bears, Riku and Kai.
"It's the second time I've worked on Christmas Day and it's a novelty," he said.
"Not many people get to spend this quality time with brown bears and polar bears - and it's just a few hours out of my day."
It is the first Christmas spent offshore for 25-year-old gas rig worker Joseph Bensley, from Great Yarmouth in Norfolk.
The senior operations technician works on the Shell Leman Alpha platform, 29 miles (48km) off the Norfolk coast in the North Sea.
Most of his 12-hour shift, which started at 06:00 GMT, will be spent checking the equipment outside, climbing up and down the eight flights of stairs on the platform.
"In the last week there have been 40 or 50-knot winds. It's cold - it makes your bones ache," he said.
"I would have been at my parents' house in Great Yarmouth. This is my first time working Christmas. I don't mind, it's part and parcel of the job.
"It's a bit disappointing as my brother is home from Hong Kong and I'll miss him on Christmas Day, but I'll see him after."
Ditch the in-laws
Jon Bennett will be scaling one of England's highest peaks to check weather conditions.
The 56-year-old is one of two fell-top assessors who take turns to make a daily ascent of Helvellyn, in the Lake District, during the winter period.
And today, as on every day he is on shift, he will be at the 3,114ft (950m) peak, collecting information on wind speeds, temperatures, snow and ice.
The report is then posted on the Lake District National Park Authority's Weatherline service.
Mr Bennett, who lives in Ambleside and has been doing this since 2007, says working Christmas Day isn't a problem.
"You don't have to celebrate it on the 25th. I visited my parents a few days ago and celebrated then. In some ways it's nicer to do it earlier."
And it can be festive up on the fell, with a surprising number of walkers, all of whom are "keen for a chat", he said.
"Many couples solve the dilemma of who to visit - parents or the in-laws - by favouring neither side of the family and going for a walk instead," he joked.
The ascent usually takes about two hours, and the descent slightly less depending on the weather.
Once home, though, he does not usually bother with Christmas dinner.
"Couldn't be doing with cooking that, not after the climb," he said. "I just eat something a bit more special than a normal meal... like a steak."
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Taking one for the team
Claire Chambers is a passenger services supervisor at Exeter Airport.
She is going to work especially to meet passengers who will arrive on the only flight on its runway later.
"My children are grown up now so I wanted to give those with younger children the day off," said Claire, from Willand in Devon.
"I'll be meeting the passengers on the TUI flight from Tenerife at 7:30pm.
"I've worked at the airport for 22 years, but this will be my first Boxing Day off."
Part of the work family
Andrea Ravese has worked at Body Worlds, and its predecessor Ripley's Believe It or Not, for four years.
He is a duty manager responsible for taking care of guests, the team, and exhibits, at one of London's only tourist attractions open on Christmas Day.
"Christmas Day is actually very fun to work - you see visitors being very festive and wearing all sorts of funny Christmas jumpers and hats," said the 26-year-old.
"People are in great spirits and customers tend to engage even more with the team - there is lots of fun banter.
"The only downside would be not spending it with family, but we make work fun and it turns out to be great every time.
"Some of our team live away from their homes and families so they love coming to work and being part of the work family Christmas Day."
Andrea, who is originally from Castelvetrano in Sicily, says he worked on Christmas Day every year since 2013 except last year, when he took it off and "kind of missed it".
Father John Caster is spending his seventh Christmas delivering services at St Barnabas Church in Tunbridge Wells.
He first worked on Christmas Day 24 years ago, and has only missed three years, while training in Oxford.
"In my last parish, I used to do a hospital round after all the services," he said.
"I enjoy being able to finish after midday now. I can decompress quickly."
The 47-year-old said one of the things he likes most about working on 25 December is seeing new members join the congregation, if only for one day.
"It is a happy day, and I love seeing the mix of people who leave their personal confines to share that joy."
However, he said Midnight Mass can bring some challenges.
"Dutch courage probably gives some non-churchgoers the confidence to come in.
"I've seen some extreme situations before - even the police being called out - but on the whole, people are merry... one way or another."
Even on 25 December, you'll find a journalist or two huddled by a heater in an otherwise empty newsroom.
This year it's me, Lauren Potts, keeping an eye on world events, alongside other BBC teams around the country and the world.
I'm hoping everyone remains on best behaviour until I can put my feet up with a glass of wine.
In the meantime, I raise a coffee cup to my fellow festive workers - a #HappyWorkingChristmas to all.
Good morning everyone and a Happy Christmas to you all, we are here to keep you company @BBCBreakfast @carolkirkwood #HappyChristmas and especially if you are working #HappyWorkingChristmas pic.twitter.com/pCYofbnCDW— Louise Minchin (@louiseminchin) December 25, 2018