Travel from Japan to Vietnam had partially resumed in June. However, Vietnam Airlines announced that the flight from Vietnam to Japan will postpone to October 24th. Due to the difference in travel restriction and quarantine policy between Japan and Vietnam, the government asked travelers to contact the Japanese embassy for getting entry permission.
In this stage, Vietnam Airlines will keep continuing flight operations as cargo flights.
Vietnam Airlines official website: https://www.vietnamairlines.com/jp/en/Home
Source: ベトナム航空、日本路線の運休を10月24日まで延長