Do you need a return or onward flight ticket to enter Vietnam (e.g. Nha Trang)?

In a recent reported case, the airline would not allow boarding until return travel was confirmed. Making a reservation through Euroavia was enough to proceed with the flight.

If you don't have a return ticket, you may be asked to buy one on the spot at check-in — it doesn't have to be to Russia, a ticket to any other country works, as long as it proves you'll leave.

Not having a return ticket could be a reason Vietnam denies entry, but it won't stop you from leaving Russia — being turned back at Russian departure requires separate legal grounds (being wanted, alimony debt, a court travel ban, etc.), not simply lacking a ticket.

On whether airlines let you board a Moscow–Vietnam flight without a return ticket to Russia — no guaranteed answer, but it's safer to have some proof of onward travel.

Having an e-visa lowers the odds of being asked for a return ticket. If unsure, call the airline (e.g. Aeroflot) in advance to confirm their requirements.

Vietnamese immigration on arrival never asks for a return ticket. The check, if any, happens on departure from your home country by the airline, roughly 50/50 odds — having an e-visa lowers that chance.

Instead of a return ticket to your home country, you can show a ticket to a third country — e.g. from Nha Trang to Laos. Reportedly this hasn't caused any issues.

Regarding a Moscow–Nha Trang flight: travelers asked whether a mere booking/reservation (unpaid) is enough, or whether a fully issued return ticket is required — and whether it's actually checked in practice.

One traveler's case: a ticket with a return date routed through a third country (e.g. departing from Kazakhstan to Russia on a specific date) was also accepted fine as proof of onward travel.