Police on Wednesday said they had seized seven modified speedboats and eight engines suspected to be linked to smuggling activities.
Officers said the vessels, which were in a car park in Tung Chung, were worth around HK$5 million.
Chief inspector Yu Pok-hon said two of the boats could travel as fast as 80 kilometres per hour, which would pose a danger to marine safety.
A 17-year-old male was arrested on suspicion of constructing vessels for the purpose of smuggling.