SEOUL; More than 31,000 foreign students who had been issued D-2 or D-4 visas were staying in South Korea illegally as of August, government data showed on Friday.
A total of 31,665 foreign students who had entered South Korea on undergraduate or language training visas were in the country without permission as of August, according to Ministry of Justice data obtained by People Power Party lawmaker Kim Hee-jung.
Of these, 21,719 had entered on D-4 visas, which are issued for language study, while 9,946 had entered on D-2 visas for university degree programmes.
The figures highlight a sharp disparity between the two groups. While 29.2 per cent of D-4 visa recipients were staying in South Korea illegally, the rate for D-2 visa holders was just 3.6 per cent.
The illegal residency rate among language students rose from 25.3 per cent in 2025 to 29.2 per cent as of August this year, reversing a downward trend that had continued since 2022, when the rate stood at 42.2 per cent.
The total number of foreign language trainees in South Korea, including those without legal residency status, fell from 89,267 last year to 74,450 as of August.
Among degree-seeking students, however, the rate has continued to decline, from 7 per cent in 2022 to 3.6 per cent in August, even as the number of foreign nationals in the D-2 visa category more than doubled over the period.
Vietnamese nationals accounted for 82.8 per cent of foreign students staying illegally.
They were followed by nationals from Uzbekistan, at 2,033; Mongolia, at 1,353; China, at 731; and Nepal, at 316.
The figures partly reflect the large presence of Vietnamese students in South Korea's non-degree programmes. According to Education Ministry data, Vietnamese students accounted for 46.1 per cent of all international students enrolled in non-degree programmes as of April 2026.
Separate data tracking newly reported cases of illegal residency among foreign students at South Korean universities showed that the number rose 12.2 per cent, from 3,631 in 2025 to 4,074 this year.
This year's figure included 1,872 degree-seeking students and 2,202 language trainees.
More universities report students' illegal residency
The number of universities reporting such cases has also increased. Among 344 universities nationwide, 190 reported cases involving degree-seeking students this year, up from 182 in 2025. The number of universities reporting cases involving language trainees increased from 186 to 208.
By region, Gyeonggi Province recorded the largest number of newly reported cases this year, at 994, up from 710 last year.
North Gyeongsang Province followed with 470 cases, South Chungcheong Province with 402 and Seoul with 401.
North Chungcheong Province saw the steepest increase, with cases jumping 158.2 per cent from 134 last year to 346 this year.
At one university in Jeonnam-Gwangju, 207 of the 690 foreign language trainees newly admitted in 2025 subsequently became illegally resident.
Kim criticised universities for prioritising the recruitment of foreign students without adequate systems to ensure their continued enrolment and legal residency.
"Universities, which should be centres of learning, have become backdoor channels for illegal residency," Kim said.
She called on the Education Ministry and the Justice Ministry to conduct a comprehensive review of the international student system, from visa screening and admissions to residency monitoring and follow-up management.
