SoKor military faces manpower crunch as low birthrate slashes troop numbers

South Korea’s military has seen its troop strength fall by a fifth over the past six years, as the country’s record-low birthrate continues to erode the pool of men eligible for mandatory service, according to a report cited by The Guardian.

The Defence Ministry warned that the decline is not only affecting rank-and-file recruitment but is also causing a shortage of officers — a gap that could undermine operational readiness. The findings were included in a report submitted to ruling Democratic Party lawmaker Choo Mi-ae, whose office later released it.

From a peak of about 690,000 soldiers in the early 2000s, South Korea’s military now counts roughly 450,000 active troops. The pace of the decline has accelerated since the late 2010s. By contrast, North Korea is believed to maintain an active-duty force of around 1.2 million, according to a 2022 Defence Ministry estimate.

Government data shows that the number of 20-year-old men — the typical age for enlistment after passing a physical exam — fell by 30 percent from 2019 to 2025, dropping to about 230,000. South Korea’s fertility rate reached a historic low of 0.75 in 2024, the lowest in the world, meaning the average woman is expected to have fewer than one child in her lifetime.

The country’s population peaked at 51.8 million in 2020 and is projected to shrink to 36.2 million by 2072. South Korea is already among the fastest-aging societies globally, posing additional challenges to its labor force and national defense.

Military officials have cited technological upgrades, a robust defense industry, and the security alliance with the United States as reasons for shortening the duration of mandatory service. At the end of the Korean War in 1953, able-bodied men served for 36 months. Today, service periods are significantly shorter, though the Defence Ministry maintains that modernized capabilities can offset reduced manpower.

Despite a 2025 defense budget exceeding 61 trillion won (£33 billion) — an amount larger than North Korea’s estimated economy — the armed forces remain about 50,000 troops below what is considered optimal for defense readiness. Of that shortfall, roughly 21,000 are in non-commissioned officer positions, the ministry said.