Classes have 35 students in primary schools and 45 in secondary and high schools, and now have to make plans to divide them into shifts and sessions.
The requirement will also apply to preschools, foreign language centers and educational activities outside of schools.
All teachers and staff working at schools and training centers must have either recovered from Covid-19 within the previous six months or been vaccinated at least once 14 days prior.
Students and staff need to maintain a distance of at least one meter.
Except for children in preschools, others must wear masks in school, have their temperature checked and complete the health declarations.
The Department of Education announced earlier this month that all schools would reopen in January 2022.
The city has around 1.7 million students at over 2,400 schools.
More than 1.3 million in primary to high schools are currently studying online.
HCMC, the epicenter of Vietnam's latest Covid-19 wave, had four months of various levels of lockdowns since late May, and has begun to gradually reopen since Oct.1.