Contestants as young as 12 will be among those taking part in next month's cross-harbour swim, though parents' concerns over their children's safety may have prevented more young athletes from joining the race.
This year's swim, on October 21, is the second since the event was revived after a 33-year hiatus. The swim will move to a new, shorter course from Lei Yue Mun on the Kowloon side of the harbour to Sai Wan Ho on Hong Kong Island, which organisers say will be easier for swimmers as it aligns with the currents. But that is not enough to convince some parents.
Vincci Kwok, the mother of a seven-year-old boy, said: "I will not let my son join the race when he is older. I cannot afford to lose him. And the water in Victoria Harbour has been polluted for years. They claim the water is safe to swim in, but I doubt it."
Just 241 of the 2,727 contestants who have registered for the 1,500 places in the race are aged between 12 and 16. Some 792 are aged between 35 and 49.
The Hong Kong Amateur Swimming Association, said safety was the top concern, and the water in Victoria Harbour had been found to be safe for swimming by the Environmental Protection Department.
Last year's swim was hailed as a great success, with no reports of incidents, although a 58-year-old man did die earlier this month while taking part in time trials at Tung Chung Swimming Pool.
Launched in 1906, the cross-harbour swim was relaunched last year after being scrapped in 1978 because of high levels of pollution in the harbour.
Among the teenagers taking part is 15-year-old Jasper Sidney Edwards, who will participate in the race with 20 friends.
"The race will be challenging, but I have been swimming since I was three years old, and I've been training for two hours a day, four times a week," he said.