Last December, South Korea began issuing C-3 visas to both permanent and temporary residents of Vietnam's three biggest cities, Hanoi, Saigon and Danang. This was done under the auspices of the country's "New Southern Policy", which aimed to bolster its ties with ASEAN and India as key partners in the southern region.

C-3 visa holders could stay in South Korea for up to 30 days with no restrictions on the number of visits for a period of five years.

However, there was a sharp increase in the number of individuals forging temporary residence documents and C-3 visa holders overstaying their visa, South Korean authorities said, explaining the decision to restrict the visa to permanent residents.

In early April, offices handling South Korean visas were bombarded with thousands of applicants waiting in queue following rumors that the country’s visa policy could change any time.

The Consulate of South Korea in Hanoi said on average they issued 300 tokens a day, but up to 3,000 people began queueing up daily.

Most Vietnamese visa applicants to South Korea came from suburban areas of Hanoi and several provinces in central Vietnam.

South Korea is one of the largest labor export markets for Vietnam. Its Yonhap News Agency reported that Vietnamese were the third largest group of foreign nationals in the country with 196,633 (8.3 percent) as of 2018.

South Korea is also one of the most popular destinations for Vietnamese tourists. The Korea Tourism Organization said over 100,000 Vietnamese visited Korea in the first three months of this year, up 30 percent year-on-year. The total number last year was 457,000.