On average, there are 30 daily ferry and boat trips carrying tourists from Rach Gia and Ha Tien towns to Phu Quoc, a tourist hotspot famous for long, sandy beaches and luxury resorts.
Under the influence of the southwest monsoon, the coast from Ca Mau to Kien Giang was hit by heavy rains, strong winds and rough seas since Wednesday, with waves climbing to 1.5 meters.
Tran Van Tai, director of the Port Authority of Kien Giang Province, home to Phu Quoc, said boat services would resume when the weather eases, and affected passengers would get full refunds.
Earlier boat services had been suspended for three days from July 11, leaving some 41,000 visitors stuck on the island.
Phu Quoc has entered the peak summer travel season, but May-October is also the rainy season there.
It received 1.4 million tourists in the first half of this year.