The An Giang Maritime Port Authority said services on routes between Ha Tien and Phu Quoc, and between Rach Gia and Phu Quoc and Nam Du in both directions would be suspended until further notice.
The An Giang Provincial Hydrometeorological Station said an equatorial low-pressure trough, combined with upper-level easterly disturbances, has brought unusually strong winds off the An Giang coast, with waves of 1.5–2.5 m.
Phu Quoc Special Economic Zone lies southwest of the mainland, about 120 km east of Rach Gia City and 45 km west of Ha Tien City.
More than 30 high-speed ferry trips normally operate daily between the mainland and Phu Quoc.
Passengers with affected tickets can obtain refunds or rebookings through the ferry operators.
Phu Quoc, voted the most beautiful in Asia by readers of American magazine Condé Nast Traveler, welcomed nearly 7.1 million tourists in the first 10 months of this year, up 34.2% year-on-year.
The island also received 1.35 million foreign arrivals between January and October, up 68.4% year-on-year and surpassing this year's target, according to An Giang Province's Department of Tourism.
October to May is the peak travel season on the island with sunny weather and clear blue sea.