The test must have been done using the RT-PCR method within 72 hours before departure or the rapid antigen methods within 24 hours.
Those who cannot take a test before arrival have to be tested within 24 hours after entering and can leave their accommodation if they are not infected.
They are required to monitor their health for the first 10 days after arrival and notify medical staff if they have symptoms of Covid.
They must also use the PC-Covid app during their stay in Vietnam.
Children under two years are exempt from testing.
Vietnam fully reopened its borders on Tuesday after nearly two years of closure.
The same day the government announced the resumption of visa waivers for citizens of 13 countries, including Japan, South Korea and several in Europe.
Vietnam closed its inbound tourism and halted grating visas for foreign tourists in March 2020. It partially reopened to tourists under a vaccine passport program last November and has received over 10,000 arrivals since.
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