South Korea’s military contracts as demographic decline hits recruitment

Sunday 10 August 2025 - 12:00

South Korea’s military has contracted by around 20% over the past six years, shrinking to approximately 450,000 active-duty personnel, according to a recent Defence Ministry report submitted to Democratic Party lawmaker Choo Mi‑ae .

The decline stems from a 30% decrease in the number of 20‑year‑old men—now numbering about 230,000—who comprise the primary pool for mandatory military service. South Korea continues to hold the world’s lowest fertility rate, reported at about 0.75 in 2024.

This demographic squeeze has led to significant challenges, particularly in filling non-commissioned officer roles—where the shortfall stands at around 21,000—and maintaining overall defence readiness. The ministry warns of potential operational strain if recruitment trends continue.

Despite a defense budget exceeding 61 trillion won (around $44 billion) in 2025—larger than North Korea’s entire economy—South Korea remains about 50,000 troops short of its target force size. Strategic factors aiding force efficiency include technological upgrades and a deepened alliance with the U.S., which have enabled a reduction in mandatory service duration from 36 months in 1953 to 18 months today.

Demographers project a population decline from 51.8 million in 2020 to around 36 million by 2072, underscoring the long-term security implications of an aging society