The driver, allegedly unregistered, drove three South Koreans from Tran Phu Street in the central coastal city to a hotel on Nguyen Thien Thuat Street, a distance of 1.5 kilometers, on Monday.
Instead of the normal fare of around VND25,000 ($1.08), he demanded VND200,000 ($8.66). When the tourists refused to pay, he is said to have used foul language and become aggressive.
When some guards of the hotel tried to intervene and help the foreigners, the driver threatened them, too. Then he demanded VND100,000, and fearing his aggression, the tourists paid him.
They reported the incident to the city's tourism association and local authorities.
The number of international tourists to Khanh Hoa Province, home of Nha Trang, grew 51 percent from a year ago to 1.17 million in the first five months of 2018. South Koreans ranked third among the number of foreign visitors to the province, after China and Russia.