The Doncaster Open Water Swimmers at Hatfield Outdoor Activity Centre had an influx of members, with about 30 teenagers joining the ranks.
It came on the back of a Facebook plea by Leon Fryer after a group of youths took to the water at Hatfield Outdoor Activity Centre.
Mr Fryer is a partner in Swimyourswim, the group which runs the events.
Hatfield had been a troublesome spot for teenagers, Mr Fryer said, who would break the fence and sneak in for a dip.
They were putting their lives at risk, swimming in the cold water without supervision, Mr Fryer's post read.
"The water is still very cold, if you're not acclimatised or used to swimming in cold water, it can disable you in seconds," the post read.
"It kills people - very quickly.
The post told of the teens' swimming taking up valuable resources which would otherwise be used for club members.
"When we come out to you, that's a member of staff taken away from keeping swimmers safe," it said.
"It's a rescue boat that's not in a position to help people in trouble (yes, even the prepared swimmers get into difficulty.
"Think about that, swimmers that are wearing wetsuits, goggles and swim caps need help occasionally because of the effects of cold water immersion, and you're in 14 degree water in your boxers. Not the best idea in the world."
Mr Fryer approached more rogues swimmers two weeks ago, and said he was abused by the youths when he asked them to get out of the water.
He urged people to share his Facebook post around Doncaster in the hope that the youths' parents would see it and reprimand them.
The post worked, but not in the way Mr Fryer anticipated, when the kids turned up to swim with the group the next week.
"About 30 of them turned up, and it was the busiest ever session," Mr Fryer said.
"They were fantastic. Really engaging and really polite
"We couldn't have asked for better teenagers."
He said he hoped they returned regularly.
"We want them to come down, and we want them to be safe," Mr Fryer said.
The club passed a milestone on Saturday, with the 1000th member signed up.
The group contains 42 out of the 72 UK ice milers - those who have swum one mile in open water which is less than five degrees.
Swimmers are only allowed to wear goggles, a cap and swimming trunks.
There are only 220 ice milers in the world.