Singapore Airlines now connects 120 U.S. cities via Southwest on a single ticket

Quick summary

Singapore Airlines and Southwest Airlines launched an interline partnership on June 8, 2026, announced at the IATA Annual General Meeting in Rio de Janeiro. Travelers can now book a single ticket combining Singapore Airlines’ long-haul network with nearly 120 Southwest destinations across the United States, connecting through LAX, SFO, or SEA. Bags check through to the final destination, and misconnect protection applies under Singapore Airlines’ interline rules.

This is an interline agreement, not a codeshare — bookings must go through singaporeair.com, travel agents, or third-party sites, not southwest.com. Southwest now counts Singapore Airlines as its eighth airline partner, and the carrier has signaled more international names are coming.

Singapore Airlines and Southwest Airlines have formalized an interline partnership that opens a direct path from Singapore Changi Airport to nearly 120 U.S. cities on a single ticket — no separate booking, no self-transfer, no hoping your bags make it.

The deal was announced June 8, 2026 at the IATA AGM in Rio de Janeiro and is live for booking immediately through Singapore Airlines and third-party travel channels. Three shared gateways anchor the partnership: Los Angeles (LAX), San Francisco (SFO), and Seattle-Tacoma (SEA) — all cities where both carriers already operate. From any of those three airports, travelers connect onto Southwest’s domestic network under a single Singapore Airlines-issued ticket.

For U.S. travelers, this means cities like Spokane, Burbank, Oakland, Knoxville, and Anchorage — places that previously required a self-connecting Southwest ticket bought separately — now sit within reach of a single SQ itinerary. The practical upside is real: through-checked baggage, misconnect protection, and one booking to manage if something goes wrong.

Southwest COO Andrew Watterson described Singapore Airlines as “the eighth carrier in our partnership portfolio exemplified by its quality and reach,” adding that international partners are “facilitating access to our network for a growing global audience.” That portfolio started from zero in February 2025 — eight partners in roughly 16 months is not a slow build.

What the partnership actually covers — and what it doesn’t

The mechanics matter here. This is an interline agreement, which means the two airlines have linked their reservation, ticketing, and baggage systems so a traveler can fly both on a single PNR (passenger name record), typically issued by the long-haul carrier. Revenue is split between the airlines under bilateral settlement rules — Singapore Airlines gets its share of the long-haul fare, Southwest gets its prorated domestic portion. Neither airline needs to operate the other’s flights or put its code on the other’s planes.

What this is not: a codeshare. Southwest flight numbers will not appear on Singapore Airlines-operated services, and Singapore Airlines segments cannot be booked on southwest.com. The Southwest airline partners page confirms that combined itineraries must be purchased through Singapore Airlines, travel agents, or third-party booking sites. If you try to build this trip starting on southwest.com, you won’t find it.

Southwest’s domestic product has also changed in ways that matter for international connecting passengers. The carrier has introduced assigned seating, optional extra-legroom seats, and a revised boarding process — moves designed specifically to attract higher-yield connecting traffic. For an international traveler arriving on a 13-hour Singapore Airlines flight, assigned seats on the domestic leg are no longer a luxury ask.

Why Southwest is doing this — and what it signals for the U.S. domestic feed market

Southwest’s interline push is not a pivot born of desperation. It is a deliberate strategy to capture higher-yield international connecting traffic on domestic legs that would otherwise fly at lower load factors. Long-haul carriers pay a premium for reliable domestic feed — and Southwest, with its dense point-to-point network across secondary U.S. markets, offers something legacy carriers’ domestic operations cannot fully replicate.

For Singapore Airlines, the calculus runs the other direction. Adding Southwest deepens access to U.S. secondary cities at relatively low cost, supporting premium yields on the SIN–LAX, SIN–SFO, and SIN–SEA trunk routes by offering more city-pair combinations. It also hedges against dependence on any single Star Alliance partner’s network decisions — Southwest sits outside all three global alliances, which gives Singapore Airlines flexibility that a deeper United codeshare expansion would not. Singapore Airlines already cooperates with non-alliance U.S. carriers including Alaska Airlines and JetBlue in its “other partners” category; Southwest joins that tier, not the Star Alliance tier.

Southwest launched its first international interline deals in February 2025 and has reached eight partners in roughly 16 months. The carrier has explicitly stated more airline partners are coming — and the pattern so far suggests a preference for premium long-haul carriers that bring high-value connecting passengers rather than low-cost competitors. Singapore Airlines’ network, which spans more than 130 destinations across 35 countries through SIA Group and its subsidiary Scoot, fits that profile precisely. If you’re tracking Singapore Airlines’ expanding U.S. presence, the airline’s Singapore stopover program adds another layer worth knowing about — a West Coast connection can double as a Singapore stay at no extra airfare cost.

How to use the new partnership on your next U.S.–Asia booking

The interline is live now, but most travelers won’t find it unless they know where to look — here is how to use it from day one.

• Search from your actual U.S. hometown, not just the gateway: Go to singaporeair.com and enter your real origin city — Spokane, Burbank, Oakland, Knoxville — as the departure point. The system should surface itineraries that include Southwest domestic legs to LAX, SFO, or SEA, then Singapore Airlines long-haul to Singapore. Compare these against existing United or Alaska routings to the same gateways.
• Check whether reissuing an existing ticket makes sense: If you already hold a Singapore Airlines ticket to LAX, SFO, or SEA but need to reach a different U.S. city, contact Singapore Airlines or your travel agent and ask whether your booking can be reissued to include a Southwest sector under the new interline agreement — rather than adding a standalone Southwest reservation with no misconnect protection.
• Understand what you won’t get on Southwest legs: Singapore Airlines KrisFlyer miles will earn on SQ-plated segments, but Star Alliance reciprocal benefits — lounge access, full partner mileage earning — do not apply on Southwest-operated domestic sectors. Plan your lounge time at the international gateway, not the domestic connection.
• Australia and New Zealand travelers: reprice your U.S. trips via Singapore: If you’re routing SYD, MEL, or BNE to the U.S. through Singapore anyway, check whether an SQ-plus-Southwest combination to your final U.S. city is cheaper or better-timed than SQ-plus-United. The gateway airport cost comparison for U.S.–Asia routes is worth reviewing before you commit to a routing.
• Watch for launch fare filings: New interline partnerships frequently come with promotional fare filings in the first weeks. SQ-plated itineraries via LAX, SFO, or SEA to Southwest secondary cities are the ones to monitor — Air Traveler Club’s Superdeal tracking for North America will flag any anomalies as they appear.

Watch: Singapore Airlines’ next quarterly traffic disclosure — covering load factors and yields on SIN–LAX, SIN–SFO, and SIN–SEA — will be the first hard signal of whether this interline is driving meaningful connecting feed. If U.S. connecting traffic rises, expect pressure to add a fourth gateway, possibly Denver or Chicago. If it stays flat, the partnership optimizes mix rather than grows capacity.

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