One of them is a 44-year-old woman who flew in from the Philippines and had received both doses of the BioNTech jabs.
Another is a 61-year-old woman from Dubai. She had been inoculated with the Sinopharm vaccines.
Neither of them showed any symptoms.
Two other patients, aged 1 and 2, arrived from Pakistan and developed symptoms last Saturday.
A three-year-old girl from France tested positive during her quarantine period at the Sheraton Hong Kong Hotel and Towers in Tsim Sha Tsui.
There were no new local cases for the day.
Meanwhile, health officials said a 42-year-old woman who left Hong Kong on August 13 for the UK had recently tested positive there.
As a result, the authorities have ordered people to get tested if they have stayed in Wing Cheung House in Sha Tin, where the woman lived during her incubation period.
In total, Hong Kong has recorded 12,074 confirmed Covid-19 cases.