US crude imports into South Korea jumped 50% year over year to 17.93 million barrels in August, making the United States the country's largest single supplier for the month even as WTI Midland commanded a record premium in the Asian spot market.

The surge anchored a broader diversification push. Asia's third-largest crude buyer imported 91.34 million barrels in August overall, nearly matching the 93.35 million barrels secured a year earlier, according to Korea National Oil Corp. data issued Sept. 25. US shipments rose 3.6% from July despite the price differential.

Platts assessed WTI Midland DES Yeosu at a premium of $34.6/barrel to front-month Dubai on Sept. 18 — a record-high differential for delivery of the light sweet US grade to the Far East. The premium eased to $31.8/b by Sept. 25 but remains steep by historical standards.

Two factors offset that cost, according to feedstock managers at two major South Korean refineries in Ulsan and Seoul and two traders at a South Korean refiner's Singapore trading office: ample US production with regular export programs delivering dependable WTI Midland cargo availability, and government freight cost support for non-Middle Eastern crude that helps cover the longer voyage to Northeast Asia.

"The steady availability of WTI Midland and other US Gulf Coast grades has made US crude a dependable alternative for South Korean refiners seeking to reduce exposure to Middle Eastern supply disruptions," the Ulsan and Seoul feedstock managers told Platts, part of S&P Global Energy, during market discussions Sept. 25-28.

Momentum set to carry into 2026

South Korea is positioned to remain Asia's top US crude buyer in 2026. Imports from the US totaled 131.09 million barrels in January-August, up 19.9% from 109.38 million barrels in the same period last year, KNOC data showed.

Non-Middle Eastern supply widened well beyond the US Gulf Coast in August. Mexican crude arrivals climbed 227% year over year to 2.98 million barrels. Algerian shipments reached 2.48 million barrels after zero a year earlier. Kazakhstan supplied 2.07 million barrels of CPC Blend, nearly double July's 1.05 million barrels.

The eight-month totals show the same pattern. Australian ultra-light and heavy sweet crude imports rose 46.4% to 20.93 million barrels, while Algerian Saharan Blend climbed 68.2% to 15.65 million barrels.

For refiners, the expanding slate of US, Mediterranean, Latin American and Oceania grades delivers flexibility in managing both crude quality and shipping risk, the Singapore-based traders and the Ulsan and Seoul feedstock managers said. For tanker owners, the shift reallocates ton-miles toward long-haul Atlantic Basin and Oceania routes at the expense of shorter Persian Gulf runs.

Middle East remains the foundation

The diversification has limits. South Korea's refineries were largely configured to process a broad range of Middle Eastern grades, and replacing those barrels entirely with light sweet grades from the Americas would not be possible, the Ulsan feedstock manager said.

Middle Eastern supplies accounted for about 62% of South Korea's crude imports in January-August, down from nearly 70% in 2025. The reduced share reflects stronger purchases from the Americas, Oceania and Africa — but Middle Eastern crude remains the foundation of the import portfolio, the feedstock managers said.

Within that segment, refiners have favored supply routes that avoid the Strait of Hormuz. Imports from the UAE increased 11.4% year over year to 101.56 million barrels in January-August, while Oman shipments surged 313.3% to 16.40 million barrels. Abu Dhabi grades shipped from Fujairah and Oman Export Blend from Mina Al Fahal offer medium-sour alternatives with direct Indian Ocean access, cutting exposure to Hormuz transit risk.

With government freight rebates for non-Middle Eastern barrels in place and US export programs running at full capacity, the commercial logic behind diversification strengthens rather than weakens — suggesting the US share of South Korea's crude slate will keep expanding into 2026, even at record premiums.