Ministry of Justice data supplied to National Assembly Education Committee Chair Kim Hee-jung put the unauthorized-stay rate for the D-4 training category at 29.2% at the end of August 2026.
The reported rate for D-4 training visas was much higher than the 3.6% for D-2 study visas. The MOJ data counted 21,719 people in unauthorized stay under D-4 and 9,946 under D-2, among category populations of 74,450 and 279,077, respectively.
D-4’s rate was 42.2% in 2022 and 25.3% in 2025, before reaching 29.2% by August 2026. Between 2025 and August 2026, the category’s total population fell from 89,267 to 74,450; its unauthorized-stay count declined from 22,546 to 21,719.
For D-2, the rate fell from 7% in 2022 to 3.6% in August 2026. Over that period, the category’s population grew from 134,062 to 279,077, while its reported unauthorized-stay count increased from 9,408 to 9,946.
Vietnamese nationals accounted for 26,220 people, or 82.8%, of the combined D-2 study and D-4 training unauthorized-stay count. A separate census by the Ministry of Education (MOE) and Korea Educational Development Institute counted 84,273 foreign students in nondegree higher-education programs on April 1, 2026; Vietnamese students made up 46.1% of that group. The census and immigration figures cover different dates and populations.
The Korea Herald reported that Kim criticized universities for prioritizing recruitment without sufficient systems to monitor enrollment and residency. That was her assessment of university oversight.
The MOE and MOJ said in February that annual university evaluations consider unauthorized-stay rates and other management measures. Their 2025 evaluation designated 16 degree-program institutions and four language-training institutions for visa issuance restrictions lasting one year from the second semester of 2026.
