Flights to San Diego started at $98 round trip from Denver on Frontier, nonstop, in our 31 October 2026 check. Seattle came next at $137 on Alaska Airlines, then Chicago at $217 and New York at $337. Every one of those cheapest fares was a nonstop into SAN.
We searched one December week, 9 to 16 December 2026, from four of the most searched starting cities for San Diego flights. Each search came back with 40 itineraries, and the price gap between them was wide: the New York fare was more than three times the Denver one.
The flight times show why. Denver is a hop of about two and a half hours, while New York is a coast-to-coast trip of more than six.
| Flying from | Lowest round trip | Airline | Stops | Outbound flight time |
|---|---|---|---|---|
| Denver (DEN) | $98 | Frontier | Nonstop | 2 h 29 to 2 h 30 |
| Seattle (SEA) | $137 | Alaska Airlines | Nonstop | 2 h 52 to 2 h 55 |
| Chicago (CHI) | $217 | Alaska Airlines | Nonstop | 4 h 45 to 4 h 47 |
| New York (NYC) | $337 | Alaska Airlines | Nonstop | 6 h 19 to 6 h 28 |
Travel 9 to 16 December 2026, all into San Diego International (SAN). Round trip, economy, one adult, taxes included. Fares change daily, so use the live search above for your own dates.
Only if you travel light. Frontier's lowest fares include one free personal item that fits under the seat, and a full-size carry-on or a checked bag costs extra. Add those before you compare.
Our search also found Frontier nonstops at $143 and Alaska Airlines nonstops at $157, taking 2 hours 31 minutes to 2 hours 51 minutes. If you're bringing a proper bag for a week, we'd price the $157 Alaska fare with its bag rules next to the $98 fare plus Frontier's bag fees before deciding.
Related: Frontier's bag fees, in full
Yes, from all four cities we checked, and on our dates the nonstop was also the cheapest option every time. That doesn't happen on many routes.
New York shows how much it matters. Alaska's nonstops cost $337 and took 6 hours 19 minutes to 6 hours 28 minutes. Its one-stop trips cost $342, just $5 more, yet took 9 hours 56 minutes to 12 hours 59 minutes. Our advice is simple: take the nonstop.
Related: Alaska Airlines bag fees and rules
Pick on schedule, because the price barely differs. Alaska's nonstops were $217 and American's were $218, a single dollar apart.
American was a touch quicker, at 4 hours 33 minutes to 4 hours 43 minutes against Alaska's 4 hours 45 minutes to 4 hours 47 minutes. We'd choose whichever departure time suits you and stop worrying about the dollar.
San Diego International (SAN) has two terminals. The new Terminal 1 opened on 23 September 2025 with 19 gates, and Terminal 2 handles the rest, so check your airline's terminal before you're dropped off for the flight home.
The airport sits about 15 minutes from downtown. MTS Route 992 runs there for $3 one way, which beats a taxi if you're staying near the Gaslamp Quarter or the waterfront.
We can't name the cheapest week of the year from one set of searches, and we'd rather say so than guess. Our numbers cover a single week in mid-December.
San Diego runs on Pacific time, the same as Seattle, 1 hour behind Denver, 2 behind Chicago and 3 behind New York. Fares change daily, so compare a few date pairs in the search above before you book.
Our 31 October 2026 check found round trips for 9 to 16 December 2026 starting at $98 from Denver, $137 from Seattle, $217 from Chicago and $337 from New York, taxes included. All were nonstop into San Diego International (SAN). Fares change daily, so run your own search above and treat these as real figures from one check.
Denver, in our check. Frontier had nonstop round trips at $98 for 9 to 16 December 2026, with more Frontier nonstops at $143 and Alaska Airlines nonstops at $157. Seattle was next cheapest at $137. Remember that Frontier charges extra for a carry-on and checked bags, so add those before comparing fares.
About 2 hours 52 minutes to 2 hours 55 minutes nonstop, based on the Alaska Airlines flights in our 31 October 2026 search. All ten of the cheapest Seattle fares were Alaska nonstops at $137 round trip for 9 to 16 December 2026. Seattle and San Diego share Pacific time, so there's no clock change.
Yes. Our 31 October 2026 check found Alaska Airlines nonstops at $337 round trip, taking 6 hours 19 minutes to 6 hours 28 minutes outbound. One-stop trips cost $5 more at $342 and took up to 12 hours 59 minutes, so the connection has nothing going for it. San Diego is 3 hours behind New York.
Roughly four and a half to five hours nonstop. In our check, American Airlines nonstops took 4 hours 33 minutes to 4 hours 43 minutes at $218 round trip, while Alaska Airlines took 4 hours 45 minutes to 4 hours 47 minutes at $217. Both fares were for 9 to 16 December 2026, taxes included.
Yes. Frontier's cheapest fares include one free personal item that fits under the seat, and a full-size carry-on or checked bag costs extra. Our $98 Denver fare is the base price before any bags. Prices for bags vary by route and rise the later you add them, so add bags when you book.
San Diego International (SAN), close to downtown. Its new Terminal 1 opened on 23 September 2025 with 19 gates, and Terminal 2 serves the other airlines. MTS Route 992 links the airport and downtown for $3 one way in about 15 minutes, so you may not need a rental car on your first day.
About this page
Written and fact-checked by the Flyingscanner team, last updated 31 October 2026. The fares quoted here come from our own live search on 31 October 2026, not estimates. Fares change until the airline issues a ticket, so check the live search on this page before you book. How Flyingscanner checks fares
