The figure included 9,300 previous cases from the northern province of Quang Ninh detected on the previous days but yet to be added to the national database.
Hanoi recorded 4,037 new cases, followed by Yen Bai, 2,230 and Vinh Phuc, 1,590. Both provinces are in northern Vietnam.
In the past 24 hours, 31 Covid-19 patients have died. Since the pandemic started last year, the death toll in Vietnam has climbed to 42,712, or 0.4 percent of all infections.
In the latest wave that hit the country in late April, more than 9.9 million cases have been confirmed and 8.2 million of them have recovered.
Around 79.7 percent of the population have received two vaccine doses.