I booked a flight to Japan from Australia via Ho Chi Minh City that originally had a layover less than 8 hours but was changed and is now 8 hours and 35 minutes. My local travel agency said that the maximum stay in the airport without a visa is 8 hours. After looking on the internet I cannot find any information that supports this claim. James
As far as we know, Vietnam does not require a transit visa for everyone who just stays inside the international zone at the airport for the next flight to other countries, no matter how long you stay inside the international zone at the airport.
Wish you all good things,