This is live pricing from Travelpayouts' aggregation of 40+ booking engines. The $418 fare is the cheapest current round-trip from San Francisco (SFO) to SEA on Alaska Airlines flight AS580, departing 2026-08-20 at 06:00 with return on 2026-08-24.

Clicking "Book this flight" opens Kiwi.com with this exact flight pre-filtered — same airline, same dates, same passenger count.