For many, a festive outdoor dip is a Christmas tradition, a chance to blow away the cobwebs and awaken the senses after too much mulled wine and mince pies.
Said to be a fantastic hangover cure, it's a refreshing way to round off the year. Expect plenty of Santa hats while you're at it.
Each year members of London's Serpentine Swimming Club brave the cold and take to the icy waters of Hyde Park's Serpentine Lake for the annual Christmas Day race.
The 'Peter Pan Cup' is a 100-yard swimming race which has happened every year since 1864.
Over at Lowestoft Beach on the east coast, hundreds gather to take a dip in the North Sea to raise money for charity during the annual Christmas Day dip.
Meanwhile, urban swimmers regularly get into the spirit at the (unheated) Brockwell Lido in South London on Christmas Day.
Tempted? Check out the UK's festive swim calender for 2019 here, there are planned swim ups for Christmas Day, Boxing Day and New Year's Day.
Click through the gallery at the top for more Christmas swimming inspiration.
