The police said Vu Ngoc Quang took the group from Nguyen Khang Street to Hang Duong Street, an eight-kilometer ride, and while their app showed the fare to be only VND192,000, he demanded more than 10 times that amount.
The four were upset and disputed the fare, but paid up before complaining at a police station in Hang Dao Street.
The police summoned Quang on Wednesday and ordered him to pay back the money and apologize to the Japanese.
A Grab Vietnam spokesperson said since Quang’s behavior was a serious violation of the ride-hailing company’s code of conduct, his contract has been terminated.
Tourists being overcharged or cheated is not uncommon in Vietnam. Last month a Saigon cyclo driver asked an 83-year-old Japanese tourist to pay VND2.9 million for a five-minute ride.
The normal rate in Saigon and other major cities is around VND100,000 per person per hour.