Daniel Bagshaw, a trainee solicitor, collapsed near the finish line of the ITU Triathlon Asian Cup near Hong Kong Disneyland on Sunday, having already completed the swimming and cycling stages of the race, reports said.
The cause of death was not immediately clear but the Hong Kong Standard quoted medical officials as saying the man may have suffered from undiagnosed heart problems.
The newspaper said he had been living in Hong Kong for several years.
"The subject suddenly fainted while taking part in sports activities and was sent to Princess Margaret Hospital where he was certified dead," a police statement said, without providing fuller details.
The race involved a 1,500 metre (1,650 yard) swim, 40 kilometre (25 mile) cycle ride and a 10 kilometre run.
A 26-year-old man collapsed after crossing the finishing line of a half marathon in Hong Kong in February, and was certified dead after being sent to hospital.