Southwest Airlines Launches Interline Partnership With Korea's Air Premia

Southwest Airlines has entered into an interline partnership with Air Premia, marking the South Korean carrier as the first to have such an agreement with a US airline. The deal gives travelers from Seoul access to Southwest's domestic network through Los Angeles International Airport (LAX).

The partnership took effect on November 4, 2025, and represents a notable step in Southwest's shift toward international connectivity. For decades, Southwest operated as a point-to-point domestic carrier with limited ties to foreign airlines. That approach is changing.

How the Partnership Works

Under the interline agreement, passengers can book a single itinerary that combines Air Premia's long-haul flights with Southwest's domestic routes. Travelers flying into LAX from Seoul Incheon can check their bags through to their final US destination without needing to collect and recheck them between carriers.

Air Premia currently operates flights between Seoul and Los Angeles, as well as other US routes, including San Francisco and New York. Passengers connecting through LAX gain access to Southwest's network of more than 100 destinations across the United States.

The agreement covers baggage handling and coordinated ticketing, though it stops short of a full codeshare arrangement. Passengers still book their tickets through each airline's own channels, but the interline framework simplifies the connection process.

A Shift in Southwest's Strategy

Southwest has historically avoided the interline and codeshare partnerships common among legacy US carriers like Delta, American, and United. The airline built its reputation on simple pricing, open seating, and a straightforward domestic model.

That model is being reworked. Southwest recently announced changes to its long-standing open seating policy, plans to introduce assigned seats, and has begun selling flights through platforms like Expedia. The Air Premia agreement fits into this broader repositioning.

Earlier in 2025, Southwest signed an interline deal with Icelandair, its first such partnership. The Air Premia agreement extends that strategy to the Asia-Pacific market, giving Southwest a foothold in traffic flows from Northeast Asia.

What Air Premia Gains

Air Premia, founded in 2017 and launched commercial operations in 2021, operates as a hybrid carrier positioned between low-cost and full-service models. The airline flies a fleet of Boeing 787-9 Dreamliners and has focused on long-haul routes from Seoul.

The partnership with Southwest gives Air Premia something it could not build on its own: a broad domestic distribution network in the US. Korean travelers heading to smaller US cities such as Nashville, Austin, or Kansas City can now reach those destinations with a single booking.

Air Premia becomes the first Korean carrier to establish an interline partnership with Southwest, according to statements from both airlines.

Industry Context

Interline agreements are standard tools in the airline industry, allowing carriers to extend their reach without operating new routes. For point-to-point carriers like Southwest, they offer a way to capture international connecting traffic without the cost of launching long-haul services.

The US-Korea travel market has grown steadily. Korean visitors to the United States numbered in the millions annually before the pandemic, and traffic has been recovering. Los Angeles remains one of the largest gateways for Korean travelers entering the US.

Competing carriers have long served this market through partnerships. Korean Air, part of the SkyTeam alliance, connects with Delta. Asiana Airlines, currently being absorbed into Korean Air, has ties to United through the Star Alliance. Air Premia, as an independent carrier, needed to build its own partnerships to compete.

What Travelers Should Know

If you plan to use the new partnership, keep a few practical points in mind. Bookings that combine both airlines will require coordination between the two systems. Baggage policies and fees may differ, so check both airlines' rules before flying.

Southwest's well-known two free checked bags policy applies to its own segments, but Air Premia's baggage rules will govern the international portion of your trip. Frequent flyer benefits do not currently transfer between the two carriers, since Southwest's Rapid Rewards program and Air Premia's loyalty scheme operate independently.

Connection times at LAX should also be considered. International arrivals require immigration and customs processing before you can transfer to a domestic terminal, and LAX is known for lengthy transfer walks between terminals.

Looking Ahead

The Southwest-Air Premia deal signals that Southwest may pursue additional interline partnerships in other regions. Executives have indicated interest in expanding international connectivity as part of the airline's broader strategy overhaul.

For Air Premia, the agreement supports its growth plans in the US market, where it competes with larger established carriers. Whether the partnership expands into deeper cooperation, such as codesharing or joint marketing, remains to be seen.

For now, the deal offers travelers between South Korea and the United States a new option for reaching cities across the Southwest network.