In Vancouver, a crowd of fearless swimmers that organizers pegged at more than 2,250 charged down the beach into the crisp waters of English Bay.
Among the massive crowd were people dressed as Vikings, cowboys, superheroes and penguins, chanting, "Polar Bear!" and singing the national anthem.
John Pentland and Chris Arcari, both 58, have been doing the swim every year together for some 36 years. Pentland always dresses as Santa Claus, while Arcari dons a Rudolph costume.
"There weren't a lot of costumes down here 36 years ago. So we just decided to dress up and it carried on. Then, as the years went on it's always a good way to wash the reindeer off," said Pentland.
It's now a tradition for their families and friends, with more than 25 people in their group dressed as reindeer. Pentland's 22-year-old son, C.J., has done the swim every year of his life — beginning with his parents dipping his toe in the water when he was one.
"I found this one a bit colder than the past years," said C.J., water dripping off his antlers. "It just seemed when we got out there, it hit you a bit harder."
"It's nothing compared to the North Pole," joked his brother Tyler, 21.
Meanwhile, it appeared the city's superheroes took a break from fighting crime. Charles Heffernan, 37, dressed as Batman and spoke in the caped crusader's gravelly voice after he emerged from the 8 degree water.
"It was pretty chilly, actually. Forgot my cape, forgot my leggings," he said. "I'll probably grab some hot chocolate, resume my life as a billionaire playboy."
Lots of international visitors took up the tradition, including a shivering Douglas Souza, 21, who travelled from Brazil to Vancouver to spend the holidays. He said his friends back home thought he was "crazy" for doing the dip.
"In Brazil it's so warm, nothing like this," he said. "But I like this experience. It's new."
In Nova Scotia, people donned tutus and neon Speedos as they leaped off a wharf and into the icy waters of the Atlantic Ocean.
Organizers said more than 150 people young and old braved the annual jump in Herring Cove, about 15 kilometres outside Halifax.
Many wore costumes and screamed as they jumped off the wharf two by two, the air temperature hovering around -3 C.
Dave Allan's red, white and black Joker makeup bled down his face as he emerged from the ocean water.
"It was really good. Refreshing," he said with a yell, clutching his black and white frizzy wig in his hands.
Gareth Whitfield of England said the atmosphere and the entertaining people is what brought him back for another jump after his first plunge last year.
Whitfield and his friend John Moakes participated in 2014's polar dip as part of Moakes' wedding celebrations. On Thursday they were both wearing Batman costumes with tutus around their waists.
"It's the atmosphere. All these people around here dressing up, doing insane things," said Whitfield before the event. "It's great."
Phaninnuch Rattana, who is from Thailand but has lived in Halifax for three months, said she wanted to take the plunge to experience something new to her: cold ocean water.
"It's a new thing," she said, wearing a Thailand T-shirt and carrying a Canadian flag. "You can't jump in cold water in Thailand. It's a once in my life (experience)."
Dozens gathered on the wharf and surrounding areas under sunny skies to take in the action, with many cheering and clapping as participants leaped into the chilly water.
Money raised at the Nova Scotia event will go to a local food bank.
Hundreds of swimmers in Oakville, west of Toronto, faced chilly temperatures of -2 degrees and gusts of wind as they plunged into the waters of Lake Ontario.
One swimmer was wearing a mask of a horse's head, while another was dressed as the Grinch.
The Oakville event raised more than $120,000 and all funds go to support clean water projects in Rwanda.