All arrivals will be required to show a negative PCR test result and to have received both doses of any vaccine approved in Oman.
The sultanate has approved the emergency use of Pfizer-BioNTech, AstraZeneca, Sputnik V, and Sinovac vaccines.
All passengers will however be required to take a PCR test on arrival and quarantine for seven days.
Oman had added Vietnam to its travel ban list in June due to rising concerns over the Delta variant.
Vietnam is currently facing its most challenging Covid outbreak, triggered by the Delta variant, and several countries have banned or imposed stricter quarantine measures for travelers from the country.
In the current wave of Covid that began in late April, the country has recorded over 377,000 cases.
It has vaccinated 18.09 million people, with 2.04 million getting two doses.