(CNN) -- Hong Kong (CNN) -- Angel Lau adjusts her iridescent blue goggles over her cherubic face, steps to the edge of the pool and dives in head first.
The 7-year-old is one of the lucky ones: Her mother enrolled her in private swim lessons since the age of 3. Many other young Hong Kongers are on lengthy wait lists as demand for public swimming lessons outstrips supply in a city that's surrounded by coastline -- yet a majority of residents can't swim, according to local water safety experts.
"It's really hard to get placed," says Candy Kwok, Angel's stay-at-home mother. "I've got several friends who put their names in every year but they haven't been lucky."
"And even if they get admitted, the classes are usually at the hottest time of the year. Public swimming pools are very crowded," adds Kwok, who send her daughter to Stanford Swim School. With an estimated 12,000 students across 21 pools, it's Hong Kong's largest private swimming institution.
Hong Kong holds a lottery, what it calls a ballot system, for government-subsidized swimming lessons. Nearly 60,000 people applied for 47,000 swim spots in the most recent 2011-2012 year, according to the city's Leisure and Cultural Services Department.
A one-hour session at Stanford costs about $15 for one hour, comparable to the cost for dance or piano lessons in this city. But publicly-backed lessons are a bargain -- a series of 10 one-hour sessions runs just $12 dollars.
Hong Kong's failure to satisfy demand for public classes sets the stage for a private business opportunity.
"I would say about 40% of all parents who cannot enroll in the government's programs choose Stanford," says Howard Fung, Director of Stanford Swim School.
"And even if you are lucky and you get a chance to participate in the government program, you're not guaranteed to be allocated (a spot) in the next term."
A majority of Hong Kong's citizens can't swim, says Alex Kwok, General Secretary of the Hong Kong Kowloon Lifeguards Union. Founded in 1968, it's the city's oldest and largest such organization.
"I feel shocked," he says, "because Hong Kong is surrounded by water and it's a big city." This Chinese territory is made of more than 200 islands with 700 kilometers of coastline - more than the distance from London to Paris and double the distance from New York to Washington, D.C.
Kwok, a lifeguard of a dozen years is well-known in Hong Kong's swim community and a vocal critic of the government. He estimates if the city's entire population of 7 million residents were thrown in the sea "less than 20% can survive".
Howard Fung of Stanford Swim School thinks it is more nuanced than that. He believes 20% of Hong Kong's elderly can swim while that number jumps to between 40% and 50% for the city's youth. The Hong Kong government does not conduct surveys on the number of citizens who can swim.
Regardless of numbers, Kwok blames Hong Kong society's emphasis on academics.
"Most Chinese, especially Hong Kongers, are not as focused on swimming or sports because they think it's useless. But I think this isn't right because children have to learn more things. You have to teach them how to survive in the water."
"Stupid thinking." he adds. "I hope more parents can open their minds."
And the recent ferry collision - Hong Kong's most fatal water disaster in four decades - still hangs fresh on many minds.
On October 1, amid fireworks for China's National Day holiday celebrating the founding of the People's Republic, 39 people died when two ferries collided. More than 100 passengers had been thrown into the sea.
Watching the accident unfold, Angel's mother - who can't swim herself - had no doubt her daughter's time in the pool is well spent.
"Since Angel can swim, she won't panic and can save herself. I think her odds of surviving a water-related accident are double."
The Hong Kong government has since announced a nearly 7% expansion of public swim classes. But the Lifeguard Union's Alex Kwok is still critical.
"I don't think this is enough. Even if they increase (public classes by) 700% it is not enough for Hong Kong's children."
So for now, parents like Candy will go where the supply is -- at private schools -- if they can afford it. Those who cannot will have to hope their names will finally be chosen next year.
CNN's Vivien Kam and Judy Zhu contributed to this report.