In July they had risen by 4% year-on-year, in August there was a 31% surge, but September saw a dramatic 84% spike, as globally travelers began planning for the Christmas and New Year holidays, Agoda said.
This increase aligns with Vietnam's international tourist numbers, which increased by 43% in the first nine months of this year.
At 12.7 million, the number was already higher than that of the whole of 2023.
Vietnam has now entered its peak tourism season, which runs from October to April.
Adding to the influx, several cruise ships carrying thousands of foreign tourists have begun to arrive.
Last Saturday the Quantum of the Seas docked at Phu My Port in Ba Ria-Vung Tau Province with 2,800 tourists who visited popular attractions in HCMC such as the Independence Palace and Notre Dame Cathedral.