San Diego (SAN) to Denver (DEN): 852 miles (1,371 km) great-circle, about 2h 10m nonstop by our estimate. Cheapest fare observed: $123 round-trip on Frontier, nonstop, departing May 5, 2026.
$123 round-trip, Frontier F92818, departing 2026-05-05 at 06:25, returning 2026-05-08. The recorded itinerary left on a Tuesday, returning on a Friday 3 nights later; the fare was observed 10 days before departure. "Book this flight" opens Kiwi.com with the same airline and dates.
At $123, it ranked 2nd of the 30 round-trip fares we recorded from SAN (median $279). That is 14.4 cents per great-circle mile (round-trip price over one-way distance), close to the SAN median of 15.0 cents across 30 round-trip routes.
Routes from SAN of similar length: Boise (750 mi) at $149 and Seattle (1,051 mi) at $172.
Frontier had the cheapest fare on 16 of 30 SAN routes. It is the 25th longest of the 30 routes we track from SAN.
Of 19 departure airports with a fare to Denver, San Diego (SAN) ranked 6th at $123. Lowest: $49 from Phoenix (PHX); highest: $382 from Guadalajara (GDL); 10 nonstop. Cheapest-fare airlines (routes): Frontier (18) and Viva Aerobus (1).
Travelpayouts fares (cheapest per route, observed April 25, 2026); OurAirports coordinates and elevations; IANA zones America/Los_Angeles, America/Denver; flight time is our estimate.