Do you need a return or onward flight ticket to enter Vietnam? Will immigration or airline staff ask for it at the airport?

The check usually comes from the airline at check-in in your departure country, not Vietnamese immigration — without proof of onward or return travel they may deny boarding.

For the visa-exempt entry (45 days for many nationalities) and for the e-visa, proof of an onward or return date is formally required.

In practice, Vietnamese immigration at Tan Son Nhat (Ho Chi Minh City) or Hanoi rarely asks for a return ticket at passport control, but it's not guaranteed and can vary by flight or terminal.

If you plan to stay longer than the visa-free period or don't yet know your exit date, it's safer to book a refundable onward/return ticket (free cancellation within 24h) than to fly with no return ticket at all.