This is live pricing from Travelpayouts' aggregation of 40+ booking engines. The $57 fare is the cheapest current round-trip from Phoenix (PHX) to SAN on Frontier flight F91571, departing 2026-09-04 at 22:33 with return on 2026-09-06.

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