Around 4:30 p.m. local fishermen found Kotelnikova Liubox, 71, lying motionless on the beach. They took her to a local medical facility for emergency first-aid, but she was already dead, local media reported.
Liubox had arrived in the coastal resort town of Mui Ne, Binh Thuan Province, with some friends the same day, the reports said, but gave no further information.
Ngo Ngoc Dung, a local official, said police are investigating the cause of death. "It has not been ascertained whether she had died of a stroke or drowning," Dung said, as cited by Bao Ve Phap Luat (Protecting the Law), the news portal of Vietnam's top prosecution office.
Last month, Russian man Aleksander Koloskov drowned while swimming in a beach in Mui Ne in a place where it is prohibited.
Last August, 10 tourists and a life guard died after being swept away by rip currents in Binh Thuan beaches.