Of the three locally-transmitted cases, one is from Hanoi and the two other are people from the central province of Quang Ngai.
Vietnam has had 789 COVID-19 cases in total. 316 cases imported from other countries were quarantined upon arrival.
333 cases traced to Da Nang have been detected since local transmission re-emerged in Da Nang on the 25th last month.
Ten virus-related deaths have been documented in Vietnam while 395 COVID-19 patients have recovered.