The Nha Trang Bay Management Board issued the warning on October 30, urging beachgoers to exercise caution when swimming or taking part in water activities.
The board said strong currents could unexpectedly sweep swimmers away from shore, making it difficult to return to safety.
High waves and rough seas could quickly exhaust swimmers, trigger panic and increase the risk of drowning without prompt assistance.
Even experienced swimmers could be at risk if they underestimated changing sea conditions, officials warned.
The management board advised residents and visitors not to judge beach safety by appearance alone and to check local warnings before entering the water.
Tourists, particularly first-time visitors, were urged to avoid deserted beaches, areas without lifeguards and locations outside designated swimming zones.
Beachgoers should also suspend swimming and other water activities whenever high waves or unusual currents are detected.
Authorities stressed the importance of following safety warnings, using designated swimming areas and cooperating with rescue personnel to prevent accidents.
The Nha Trang Bay Management Board's rescue team has provided an emergency hotline, 0913 476 476, for reporting incidents and requesting assistance.