The two men flew in from Kenya and Pakistan, and both had received two doses of the Sinovac vaccine.
The two, aged 35 and 43, did not show any symptoms.
Separately, health authorities said a 52-year-old woman tested positive for the coronavirus in the United Kingdom two days after she left Hong Kong. She had tested negative three days before her flight.
The patient earlier received two doses of the Sinovac vaccine on the mainland.
The Centre for Health Protection told people who had stayed at the Butterfly On Prat Boutique Hotel in Tsim Sha Tsui, where the woman stayed during her time in the territory, to get tested.