Southwest Airlines is taking another decisive step toward global connectivity with a new interline partnership with Turkish Airlines, significantly expanding its international reach and marking the largest alliance the U.S. carrier has entered to date.
The agreement allows passengers to book single-ticket itineraries that combine flights operated by both airlines, simplifying travel between Southwest’s extensive domestic network and Turkish Airlines’ vast global route map.
The partnership represents a notable evolution for Southwest, which for decades avoided interline agreements and code-sharing in favor of operating as a largely standalone carrier. That long-standing philosophy has shifted rapidly over the past year as the airline adapts to changing traveler expectations and competitive pressures.
Turkish Airlines now joins a growing list of international partners that includes Icelandair, EVA Air, China Airlines, Philippine Airlines, and Condor, whose partnership with Southwest is set to begin in January.
Turkish Airlines brings substantial global scale to the relationship. The Istanbul-based carrier serves dozens of destinations across Europe, Asia, Africa, and the Middle East, with nonstop service to 14 U.S. cities. Under the new agreement, 10 of those U.S. gateways will be included in the interline arrangement with Southwest, offering travelers smoother connections between Turkish’s long-haul international flights and Southwest’s domestic routes across the United States.
Single-ticket itineraries will initially be available through Turkish Airlines’ sales channels and travel agencies, with bookings expected to open early next year. Southwest has confirmed that joint itineraries will not be bookable through its own website or mobile app at launch, as the airline continues to develop the technology needed to support partner-airline bookings within its digital ecosystem.
Despite this limitation, the interline agreement is expected to be particularly valuable for international travelers arriving in the U.S. and seeking convenient onward connections.
For Southwest, the partnership underscores a broader strategic shift toward flexibility and global relevance without committing to long-haul international operations of its own. By relying on interline agreements, the airline can extend its network footprint while maintaining its core focus on short-haul and medium-haul markets, operational efficiency, and its point-to-point business model.
The addition of Turkish Airlines is especially significant given the carrier’s reputation as one of the world’s most connected airlines. Istanbul’s role as a major global hub offers Southwest passengers indirect access to destinations far beyond the airline’s traditional scope, from major European capitals to emerging markets across Africa and Asia.
Industry analysts see the move as a sign that Southwest is positioning itself more competitively in a market where travelers increasingly expect seamless global journeys, even when flying with traditionally domestic-focused airlines. While the airline’s interline strategy remains selective, the scale of the Turkish Airlines partnership suggests that Southwest’s approach to international cooperation is no longer experimental but foundational to its future growth.
