This is live pricing from Travelpayouts' aggregation of 40+ booking engines. The $309 fare is the cheapest current round-trip from Chicago (MDW) to SFO on Southwest flight WN4327, departing 2026-10-16 at 21:25 with return on 2026-10-19.

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