Beginning next month, the mandatory quarantine policy will be applied on arrivals from 20 nations, down from the current list of 36 countries, according to the Korea Disease Control and Prevention Agency.
Zambia and Djibouti were newly added to the list, while 18 countries, including Russia, India, Japan and the United Arab Emirates, were removed.
South Korea has been allowing arrivals who have been fully vaccinated abroad to enter the country without going through the two-week self-isolation.
They are still required to visit South Korea only for business, academic and humanitarian purposes.
Amid growing concerns over the COVID-19 variant cases, the country has been making it mandatory for arrivals from some countries to go through quarantine regardless of their vaccination status.
On Friday, the country added 2,008 COVID-19 cases, including 1,973 local infections, raising the total caseload to 281,938.