Despite the end of the peak tourism season, May alone saw 1.53 million foreign arrivals, marking the highest number for the month in the past decade, according to the General Statistics Office.
Mainland China remained the top source market during the January-May period, with 2.36 million arrivals, followed by South Korea (1.9 million), Taiwan (532,000), the U.S. (375,000), and Japan (342,000).
Russia posted the highest growth during the five-month period, with arrivals surging 221% year-on-year.
The Philippines followed with over 200% growth, Cambodia with more than 160%, and India with over 134%.
Tourism experts attributed the strong performance to favorable visa policies, expanded promotional campaigns, and a series of events held to celebrate major national holidays.