The number of South Korean overseas tourists appears to have fallen steadily since the Sewol ferry sank in April, killing 288 passengers with 16 still missing.
About 142,000 people travelled abroad in May through Hana Tour, South Korea's largest travel company, the company said. The figure is down 5.7 per cent from the same month last year.
So far 107,000 have booked to go abroad in June, down 12.1 per cent from a year earlier.
"New travel reservations made after the Sewol ferry sinking decreased by 50 per cent," said Cho Il-sang, director of the firm's PR division. "Of course, the Sewol sinking is not the only factor behind the falling number of overseas tourists, but it seems to have had a big negative impact on plans for overseas travel."
In April, the number of overseas travellers rose 7 per cent from a year earlier.
Japan and Southeast Asia region had the largest fall in May. According to Hana Tour, the number of South Koreans travelling to Japan plunged 28.4 per cent from the same month last year. The number of visitors to Southeast Asian countries declined by 19.1 per cent over the same time span.
Japan and Southeast Asia are two of the most popular tourist destinations for South Koreans. Travelers to the southern Pacific region, a popular destination for families, decreased by 6.3 per cent.
Cho attributed the drop in the number of tourists visiting the Southeast Asian region to political unrest in Thailand and a deadly typhoon that hit the Philippines last year.
While backpacking trips and individual trips increased in May by 41 per cent and 34 per cent, respectively, thanks to a four-day weekend, group tours for students and government officials declined by 29 per cent.
Korea's second-largest tour company, Mode Tour, also reported a 4.4 per cent decrease in the number of Koreans traveling overseas in May. About 69,300 of its customers went abroad that month. It said the numbers of tourists to China and the Southeast Asian region fell more than 20 per cent and 12.9 per cent, respectively.
"New bookings have just returned to normal. We expect the numbers of tourists will recover fully this month. Customers are beginning to resume cancelled and postponed trips," said Cho.