Armed forces down to about 450,000 due to low birthrate

Soldiers of the Army’s 51st Infantry Division simulate a response to an enemy drone attack during an integrated defense drill at a plant in Gwangmyeong, Gyeonggi Province, June 16. Yonhap

The size of South Korea’s standing military force has fallen to about 450,000 personnel, around 110,000 fewer than six years ago.

This reduction includes 17 divisions and other large units that have been disbanded or merged, according to figures obtained from the Ministry of National Defense and the Military Manpower Administration by Rep. Choo Mi-ae of the National Assembly’s Legislation and Judiciary Committee.

These figures illustrate a steady decline from 563,000 in 2019 to the current level as of July 2025. The Army has been hit hardest by the reduction, losing more than 100,000 troops during this period. At the same time, the selection rate for career officers has dropped to roughly half of previous levels, making it increasingly difficult to secure long-term service members.

The restructuring has been most keenly felt in the northern border regions of Gangwon and Gyeonggi provinces, where several combat formations have been consolidated or dissolved. The remaining units are now responsible for wider defensive sectors — a shift that some analysts warn could strain personnel and reduce operational responsiveness.

Defense officials point to Korea’s record-low birthrate as the main reason for the shrinking pool of conscripts, a trend that is expected to intensify in the coming years. Even with adjustments to force size, they acknowledge that this demographic reality poses long-term challenges to maintaining readiness.

In an attempt to slow the decline, the defense ministry has considered introducing measures such as increasing the recruitment of female soldiers, offering bonuses for short-term service and reducing the number of men assigned to noncombat supplementary duties. However, critics contend that these efforts will not be enough to offset the structural shortage.

A senior official from the defense ministry, speaking on condition of anonymity, said that while advanced weapons and improved training could partly compensate for fewer troops, “there are limits to replacing people with technology, especially when facing a heavily armed adversary right across the border.”

The timing of the decline is particularly concerning given North Korea’s ongoing nuclear and missile programs. According to experts, regional security tensions, coupled with the drawdown of conventional ground forces, could erode deterrence unless matched by credible alternative capabilities and strengthened cooperation with the United States.

The ministry has indicated that it is reviewing broader restructuring plans in order to make better use of available personnel, streamline training and reinforce rapid-response capacity. Lawmakers from both ruling and opposition parties have urged a more detailed, long-term strategy to prevent any compromise in readiness.

Choo, who made the data public, urged the government to “recognize the scale of the challenge and prepare for the security environment we will face in the decades ahead.” She added that the debate is not theoretical: “It’s a matter of who will be there to defend the country when the time comes.”