South Korea's Aero K Airlines begins SAF use on Cheongju-Japan route

South Korea's Aero K Airlines has begun using sustainable aviation fuel on its route from Cheongju, South Korea, to Kitakyushu, Japan, marking the first commercial deployment of SAF from the Cheongju International Airport.

The South Korean low-cost carrier started SAF use on the Japan-bound route on Dec. 16, operating three flights per week during the winter season, the airline said. The fuel is being supplied through a partnership with GS Caltex.

SAF used on the route is produced from waste-based feedstocks, such as used cooking oil and animal fats, and can deliver lifecycle greenhouse gas reductions of up to 80% compared to conventional jet fuel, according to the airline.

Market participants said the move underscores the growing voluntary adoption of SAF by Asian carriers, even as the region lags behind Europe in regulatory enforcement. Unlike the EU's ReFuelEU Aviation framework, which mandates SAF blending starting in 2025, South Korea currently relies on pilot programs and voluntary initiatives, with no nationwide blending obligation in place.

Industry sources said limited policy certainty continues to constrain large-scale SAF offtake in Asia, resulting in small volumes and elevated costs. Airlines introducing SAF on select routes are largely absorbing the price premium or leveraging partnerships with domestic refiners to manage costs.

GS Caltex, one of South Korea's key refiners, has been positioning itself to supply SAF as regional demand gradually develops, while airlines such as Aero K see early adoption as a way to align with international carbon reduction frameworks and future compliance requirements.

Aero K said it plans to gradually expand SAF usage across its network, although market participants said that a broader rollout will depend on feedstock availability, price competitiveness, and clearer policy signals from the South Korean government.

The initiative comes amid growing regional momentum to decarbonize air travel, with Japan and South Korea advancing SAF trials and deployment across domestic and short-haul international routes.

Japanese carriers, including ANA and JAL, have already incorporated SAF into limited flights, while South Korean carriers have largely focused on testing SAF for long-haul operations. Aero K's Cheongju deployment underscores a broader shift among smaller carriers and secondary airports toward practical, scalable SAF adoption.

The move also positions Aero K and other Asian carriers to navigate international regulatory pressures. Under the Carbon Offsetting and Reduction Scheme for International Aviation, or CORSIA,, airlines operating on international routes are required to offset their emissions growth beyond 2019 levels.

While Aero K's domestic-focused network is currently outside CORSIA's immediate scope, regional airlines with expanding European operations will face increasing cost and compliance pressures, particularly if they do not integrate SAF into their fuel mix.

European regulators' SAF mandates, such as the RefuelEU Aviation initiative, require minimum SAF blending for all flights departing EU airports, creating a potential financial and operational exposure for Asian carriers flying to the region.

Early adoption of SAF on intra-Asia routes, as Aero K is doing, could provide valuable operational experience and supply chain relationships, helping carriers meet future EU SAF obligations and offsetting compliance costs under both CORSIA and EU legislation.

Platts, part of S&P Global Energy, assessed SAF prices basis CIF Northwest Europe up about 15% year-to-date at $2,342/metric ton on Dec. 15, after touching a high of $2,921/mt in November, as buyers scrambled to secure barrels for ReFuelEU mandate compliance.

In Asia, SAF prices basis FOB Straits started the year at $1,946/mt, climbed to highs of $2,796/mt in November before easing to $2,234/mt on Dec. 15, according to Platts assessments.