Southwest Airlines Partners with Singapore Airlines on Interline Agreement

What happened

Southwest Airlines and Singapore Airlines formed an interline partnership allowing travelers to book single-ticket journeys connecting both carriers' networks. The agreement was announced at the IATA Annual General Meeting in Rio de Janeiro on June 8, 2026. The partnership operates through three shared US gateway airports: Los Angeles (LAX), San Francisco (SFO), and Seattle/Tacoma (SEA). International passengers arriving on Singapore Airlines flights at these gateways can now connect to nearly 120 airports in Southwest's domestic network. Conversely, US travelers can access Singapore Airlines' extensive network of more than 130 destinations across 35 countries and territories in Asia, Europe, Africa, Australia, and the South Pacific. Tickets are available through Singapore Airlines' website, travel agents, and travel platforms. Chief Operating Officer Andrew Watterson stated the partnership facilitates access to Southwest's network for a growing global audience and creates consistent high-quality customer experiences.

Why it matters

This partnership significantly expands Southwest's international reach without requiring the carrier to operate long-haul flights itself. For Southwest customers, the agreement opens access to numerous international destinations previously unavailable through the airline's predominantly domestic network. For Singapore Airlines passengers, the partnership provides connections to dozens of secondary US cities and leisure destinations not easily accessible through other airline partnerships. The interline structure allows both carriers to leverage their respective strengths-Southwest's extensive domestic point-to-point network and Singapore Airlines' global hub operations. This creates new revenue opportunities for Southwest while enhancing its competitive position against carriers offering more comprehensive international connectivity.

Bigger picture

The Singapore Airlines agreement marks Southwest's eighth interline partnership and its fourth new international partnership within the past year, joining recent deals with China Airlines, All Nippon Airways, and Condor. Southwest's existing partnership portfolio also includes EVA Air, Icelandair, Philippine Airlines, and Turkish Airlines. This rapid expansion of international partnerships represents a strategic shift for Southwest, which has historically focused almost exclusively on domestic operations. The move reflects broader competitive pressures in the US airline industry, where carriers are seeking new revenue streams and enhanced network connectivity. Unlike traditional codeshare agreements where airlines share flight codes and sell seats on each other's flights, interline partnerships coordinate passenger itineraries and baggage handling across carriers while maintaining separate ticketing systems. Southwest has indicated it will continue pursuing additional transpacific and transatlantic partnerships, suggesting further expansion of its global network connectivity without capital investment in long-haul aircraft.

What to watch

Monitor whether Southwest announces additional interline partnerships, particularly in transatlantic markets where the carrier currently has limited coverage. Watch for potential expansion of booking channels beyond Singapore Airlines' website to include Southwest's own platforms and additional travel distribution partners. Observe passenger uptake and revenue contribution from the growing portfolio of international partnerships as indicators of whether this strategy successfully enhances Southwest's competitive position. Track any operational challenges related to baggage handling, connection coordination, or customer experience at the three gateway airports, as smooth execution will be critical to the partnership's success.