Students in local schools will continue to learn at home until the end of the Primary School Leaving Examination (PSLE), which is sat until October 6.
Students in Years 1-6 at international schools across Singapore, which are regulated by the Committee for Private Education (CPE), have also moved to online learning.
In the latest wave of Covid-19, Singapore expects to see 1,000 new cases a day.
The Ministry of Education (MOE) hopes to minimise the risk of school-based transmissions and reduce the number of students placed on Quarantine Order (QO) or Leave of Absence (LOA) prior to the PSLE examination, which is taken by all Primary 6 students at the end of the Singaporean academic year.
Singapore's vaccination programme is open to all secondary-age students aged 12 and above.
The MOE said:
"This will better protect our younger students who are not yet medically eligible for vaccination."
The PSLE runs from September 30 until October 6, and Primary 6 students will start study leave from September 25 ahead of the exam.