National Assembly Library publishes data report on prison overcrowding

The National Assembly Library said Friday it had published the 49th issue of its "Data & Law" series, focusing on overcrowding in South Korea's correctional facilities.

Correctional overcrowding refers to a state in which the number of inmates held at a facility exceeds its designated capacity. The Constitutional Court ruled in 2016 that overcrowding severe enough to prevent inmates from meeting basic needs violates human dignity and is unconstitutional, and the Supreme Court recognized the state's liability for damages in 2022. Despite those rulings, overcrowding has continued to worsen.

The occupancy rate at correctional facilities fell from 115.4 percent in 2017 to 106.4 percent in 2021, but has since climbed back, reaching 127.7 percent in 2025 — the highest level in the past decade. As of June 2026, the inmate population had declined to 63,048, bringing the occupancy rate down to 124.6 percent, but the total still exceeded designed capacity by 12,434 people.

A comparison of 10 OECD member countries based on the 2026 World Prison Brief found that South Korea's occupancy rate of 129 percent was 18.9 percentage points above the surveyed average of 110.1 percent.

At the facility level, 48 of the country's 55 correctional institutions — or 87.3 percent — were over capacity as of June 30, 2026, and 12 had occupancy rates of 130 percent or higher. Seoul Detention Center recorded the highest rate at 147.8 percent, followed by Incheon Detention Center at 145.0 percent and Suwon Detention Center at 142.8 percent. By facility type, detention centers had the highest occupancy rate at 132.6 percent, compared with 121.7 percent for prisons and 116.2 percent for branch facilities.

Meanwhile, from 2017 through June 2026, the number of convicted inmates rose by 6,306, or 17.4 percent — a larger increase than the 1,544, or 8.1 percent, rise in pretrial detainees. As a result, the share of pretrial detainees in the total inmate population fell from 34.5 percent to 32.6 percent over the same period, remaining within a range of 32 to 36 percent over the past decade.

The share of parolees among those released — either at sentence completion or on parole — rose 13.9 percentage points, from 26.1 percent in 2016 to 40.0 percent in 2025. In the first seven months of 2026, 10,225 inmates completed their sentences while 8,986 were released on parole, putting the parole rate at 46.8 percent, up 6.8 percentage points from the 2025 figure.

Kim Seong-wan, director of the library's Legal Information Division, said the report "examines recent occupancy rates and overcapacity conditions at individual facilities through objective data," adding that he hoped it would serve as a reference for legislative and policy discussions on prison overcrowding and help build a comprehensive understanding of inmate conditions and the structure of the correctional population.