The average number of daily infections in the first week of May was 568, which is a notable drop from last month when the average topped 600 every week.
The country's R-number, which shows the rate of infection, also dipped below one. An R naught number of less than one means the disease will decline and eventually die out.
Meanwhile, on the first day of vaccine bookings for those aged 70 to 74 on Thursday, more than 11 percent booked their vaccine slots.
So far, just over 7 percent of South Korea's population have received at least their first dose of the vaccine.