Hundreds of swimmers splashed into the chilly waters of South Boston’s Dorchester Bay New Year’s morning to welcome 2013.

A penguin even took the plunge Tuesday.

A few latecomers sprinted to make it in with the group.

One swimmer crashed into a wave.

This swimmer reacted to the chilly water.

Swimmers were excited about the plunge.

Dorchester residents and supporters of the Leahy-Holloran Community Center plunged into the waters off of Tenean Beach Tuesday afternoon.

Robert Genduso, 46, of Dorchester led Tuesday’s countdown.

The swimmers were welcoming in 2013 and raising money for a community center that is the backbone of the Neponset and Port Norfolk communities in Dorchester.

Swimmers sprinted into the water.

The swim was started in 2012 and this is the second time residents have taken the plunge to benefit the center and remember one of the men the center is named after, Brain Leahy.

Leahy, who died in 2009, was a pivotal figure in the neighborhood. Often referred to as the “Godfather of Boston State College Football,” the Dorchester native worked tirelessly to bring more people to Tenean Beach and encourage residents to embrace the beauty in their own backyard.

One swimmer jumped in head first.

While the waters were chilly, the National Oceanographic Data Center estimated water temperatures hovered around 40-degrees, it was the air and the wind that had swimmers thinking about returning to the water.

Sheila Leahy, Brain Leahy’s niece, led a few warm up exercises.

A veteran of last year’s swim, Michael Goodblatt, 48, of Roslindale, jumped in for the second time Tuesday.

Swimmers sprinted out of the water as quickly as they could.

The crowd was chanting "It's not that cold!" seconds before taking the plunge.

The Annual L Street Brownies Polar Bear Swim, which is sponsored by the City of Boston/Boston Centers for Youth and Families/Curley Community Center and the L Street Brownies. Participants take the frigid plunge for fun and to raise money for a variety of causes.

The annual “polar bear” swim, thought to be the oldest in the country, has been officially organized by the L Street Brownies since 1901.

“It’s a feel good thing,” said Jack Dever, president of the L Street Brownies, a swimming club based in South Boston. “It’s always a lot of fun and it’s great to see so many families down here.”

To the left: Chico Malkofsky, 66, a South Boston resident led Tuesday’s procession.

Both the young and the old, the natives and the out-of-towners, some in costume, jumped into the freezing waters off the L Street Bath House Tuesday. The National Oceanographic Data Center estimated water temperatures hovered around 40-degrees and the air was in the low-30s with a healthy breeze when swimmers took the plunge.

Jim Zawiska, 34, of Waltham came in costume Tuesday. He was raising money for his synagogue.

“We’re freezing!” said Brigid Forestier, a 20-year Billerica resident as she waited to get into the bath house.

To left: Brigid Forestier, 20, a Billerica resident waited with her friends, Jake Myers, 13, of Billerica; David Poier, 48, of Arlington; Trina Forestier, 12, of Arlington; and Alex Sahtouris, 20 of Billerica.

For many this was their first time jumping in with the Brownies, but for one woman this was just another tradition. Dorothy Kerzner an 83-year-old yoga teacher from Danvers has been jumping in the waters off South Boston since 1971, when she was the first woman invited by the Brownies to take part in the swim.

“It’s like being baptized,” said Kerzner, who started her swim like she has for the past 43-years, doing a headstand. “It’s a fabulous time, it’s a lot better than drinking for New Years.”

One of the younger swimmers Tuesday was Jack Donaldson, an 11-year-old from Harvard, MA.

“I went swimming in it on Thanksgiving and that wasn’t too bad,” said Donaldson. “I don’t want to freeze to death so I’m going to run in really fast.”

Tim, 56, and Peter Regan, 53, were also getting ready for the swim with a little champagne. The two Boston residents have been doing the swim for over 20-years.

“The camaraderie is great and the feeling after the swim is exhilarating,” said Tim Regan.

Swimmers eventually lined up on the beach and charged into the water Tuesday with many screaming in pain and excitement as they hit the water.

Patrick Murphy, 51, and Patrick Murphy Jr.,19, of Lincoln ran towards the water.

Swimmers splashed into the chilly water.

Anna Salate, 21 of Worcester emerged from the water a little chillier.

“It was very cold, but fun,” Salate said.

Some prepared for the chilly waters with thick bathing suits and caps, but Jacqueline Kennedy, 47, of Troy, NH, shaved her head to support those fighting cancer.

Swimmers lined up waiting to get into the L Street Bath House in South Boston.