Seoul is the capital city of South Korea, home to roughly 10 million people and located about 50 km from the North Korean border. It is the country's political, financial, and cultural centre, and home to the KOSPI stock exchange.

Why did the KOSPI crash in March 2026?

South Korea's KOSPI fell 12% in a single session — its worst day on record — when the Strait of Hormuz appeared to close during the Iran conflict. South Korea imports the bulk of its oil and LNG from Gulf sources, making it acutely sensitive to supply disruption.Source: Lowdown

How far is Seoul from North Korea?

Seoul is approximately 50 km south of the Demilitarised Zone (DMZ) that divides the Korean Peninsula. This proximity has defined Seoul's security posture for decades and makes THAAD missile defence a political priority.

Background

Seoul, founded in 1394 as Joseon's capital, is today a city of roughly 10 million and the political, financial, and cultural heart of South Korea. Home to the Blue House presidential residence and the headquarters of the Korean Peninsula's principal financial exchanges, Seoul sits 50 km from the Demilitarised Zone separating it from North Korea, making it perpetually exposed to both peninsular risk and global shock.

The Iran conflict exposed Seoul's structural energy vulnerability with blunt force. When the Strait of Hormuz appeared to close in early March 2026, South Korea's KOSPI fell 12% in a single session, its worst day on record, as markets priced in supply shock for an economy that imports the vast majority of its oil and LNG from Gulf sources . Rising Brent prices feeding a $90-95 corridor deepened the inflationary pressure .

Seoul's dilemma is the one facing every US-alliance capital without Gulf oil alternatives: the THAAD interceptor stock that protects it is the same arsenal burning through Gulf air defence missions , and the AI governance laws Seoul is pioneering domestically mean little if its export-dependent economy buckles under a prolonged energy shock.

Seoul is also the reference point for South Korea's new regional-depopulation policy. The F-1-D 'workation' Visa, made permanent on 30 June 2026, deliberately excludes Seoul, Incheon and Gyeonggi Province from its lower income threshold: under-35s settling elsewhere qualify at roughly per-Capita GNI, while those choosing the capital region face the pilot's stricter, higher bar. The exclusion treats Seoul's gravitational pull on population and jobs as the very problem the Visa is designed to counteract.

More questions

How does the Iran war affect South Korea's economy?

South Korea is one of the world's largest importers of Gulf oil and LNG. Rising Brent Crude prices toward the $90-95 corridor triggered by the Iran conflict drive inflation and weaken export competitiveness. The KOSPI's 12% crash on the day Hormuz appeared closed was the most direct market signal.Source: Lowdown

Does the Iran war affect South Korea's missile defences?

Yes. The THAAD interceptor stock shared with US forces in the Gulf is the same arsenal that provides part of Seoul's layered defence against North Korean missiles. With 100-150 THAAD interceptors expended in the first eight days of the Iran conflict, replenishment is estimated to take two to three years.Source: Lowdown

Does Seoul qualify for South Korea's cheaper workation visa route?

No. The F-1-D Visa's lower income threshold, made permanent on 30 June 2026, applies only to under-35s settling outside Seoul, Incheon and Gyeonggi Province. Applicants choosing Seoul face the stricter, higher bar.Source: Korea Herald

How the World Sees Them

China

Beijing watches Seoul's economic distress from the Iran conflict as useful leverage: a South Korea weakened by energy shock is one more likely to soften its alignment with Washington. China's own restrained response to Hormuz tensions signals it is in no hurry to stabilise a crisis hurting a regional rival.

North Korea

Pyongyang reads every South Korean vulnerability as an opportunity. A Seoul distracted by market collapse, energy inflation, and depleted missile defences is exactly the strategic environment North Korea's leadership calculates against when assessing coercive options on the peninsula.

South Korea

Seoul anchors an economy structurally dependent on Gulf energy; any Hormuz disruption is felt first and hardest on the KOSPI. The 12% single-session crash in March 2026 confirmed the capital's exposure as a direct casualty of a war it plays no part in.

United States

Washington views Seoul as a frontline ally in Northeast Asia whose strategic deterrence depends on shared THAAD stocks. The Iran conflict is draining that shared arsenal faster than Lockheed Martin's Alabama plant can replenish it, creating a defence-resource tension Washington has not publicly resolved.