Until recently, Kenrick was content to while away his free time across the street from his house in Bayswater Park, which overlooks Jamaica Bay. Now and then, he and his friends kick a soccer ball around, but mostly they talk — about school, about girls, about favorite video games and, of course, about the hurricane that ravaged the Rockaways last fall.

“I was awake the entire night,” said Kenrick, recalling the evening of Oct. 29 when Hurricane Sandy inundated much of his neighborhood. “The water was coming slowly at first and then it started rushing onto our street from both directions. It was scary.”

The sense of helplessness that arrived with the storm surge helped spur him to finally learn to swim. Five of the eight Rockaways residents killed by the hurricane drowned.

Five years earlier, Kenrick’s best friend, Raynald Chance Belmont, 15, had learned from Swim Strong, which is administered and staffed entirely by volunteers. Because swim lessons typically cost as much as $1 a minute, learning to swim can be something of a luxury, not unlike sleep-away camp or private tutors, affordable mainly to affluent families.

But Swim Strong is only one of a number of programs giving free or low-cost swim lessons to New Yorkers. The largest, by far, is a program called Learn to Swim offered by the city’s parks department, which provides free swim lessons at select pools through an online lottery system throughout the year. In the fiscal year that ended in June, the department taught 27,709 children and 1,110 adults to swim. It has taught an additional 24,000 second-grade students through a new program called Swim for Life.

After Chance learned to swim, his father, Ray Belmont, asked if he could sign up for lessons, too.

“It was always a goal,” recalled Mr. Belmont, 39, a property underwriter. “It was huge for me. It was a big accomplishment. I’m two blocks from the ocean and before, if something happened to my children, I wouldn’t be able to help them. As an adult, there’s a different kind of fear. I had to overcome that by getting lessons for myself.”