The central city of Da Nang topped the list, followed by Da Lat and Nha Trang, based on accommodation searches for check-in dates from April 4-7.
Vietnamese people celebrate the kings' death anniversary on the 10th day of the third lunar month, which falls on Monday, April 7, this year, meaning people will enjoy a three-day break including the weekend.
The dry season in Phu Quoc runs from November to April, offering sunny weather ideal for outdoor beach activities.
Phu Quoc was voted last year the world's second most beautiful island by American magazine Travel + Leisure, after Maldives.
The island welcomed 1.4 million tourists, including 320,888 foreigners, in the first two months of this year, marking a 52.7% year-on-year increase.