What happened
- Connectivity: Passengers can seamlessly connect from international SIA flights to nearly 120 Southwest destinations.
- Mileage: The partnership is interline only, not codeshare or alliance-based. Singapore Airlines passengers will not earn KrisFlyer miles on Southwest-operated flights, nor will Southwest passengers earn on SIA flights.
- Baggage & Protection: The Most Significant Carrier (MSC) rule applies for baggage allowance. Passengers are protected against delays and cancellations under the MSC's rules.
- Availability: Tickets are available through Singapore Airlines, travel agents, and travel websites. This marks Southwest's expansion into legacy-style interline partnerships, previously limited by IT constraints. While SIA business class passengers may find themselves on Southwest's main cabin, the single-ticket convenience remains the primary benefit
Southwest Airlines and Singapore Airlines announced a new interline partnership during the IATA Annual General Meeting in Rio de Janeiro on June 8, 2026. This agreement allows Singapore Airlines to sell single-ticket journeys connecting to Southwest's US domestic network at three key gateways: Los Angeles (LAX), Seattle/Tacoma (SEA), and San Francisco (SFO). Key details for frequent flyers: