This is live pricing from Travelpayouts' aggregation of 40+ booking engines. The $320 fare is the cheapest current round-trip from Montreal (YUL) to SFO on WestJet flight WS859, departing 2026-07-17 at 06:45 with return on 2026-07-20.

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