Singaporean Izwan Abdullah was on a six-day holiday with his parents and an aunt when the incident happened in the Thai capital, Bangkok.
He said he was alone in a taxi travelling from Chatuchak Weekend Market back to his hotel just outside of town when he was stopped at a road block manned by anti-government protesters.
The mood in the city was tense, he said.
Said the 18-year-old, who is awaiting enlistment into national service: "We were driving past the roads near the Royal Thai Armed Forces Headquarters when I was stopped and one of the protesters asked the driver if I was a local.
"I was a little scared because it was a big group, but the taxi driver told them I was a tourist and I was allowed to go on my way."
The family returned to Singapore on Monday.
Speaking at Changi Airport, just after their arrival, Mr Izwan said: "At Siam Paragon on Saturday, I spoke to a protester who said they try their best not to scare tourists who are the number one source of income for the country."
Other Singaporeans there also said it was business as usual in the city even as thousands of protesters took to the streets, blowing whistles and banging drums.
Singaporean Wong Man Ling said she did not see any clashes even though she stayed near a protest site in Bangkok.
"When I was there, we didn't see any violence, just thousands of people lining the roads outside Asok BTS, near where we stayed," said the 27-year-old leasing executive.
"The local businesses and tourists didn't seem affected by the protests either," she added.