Find Cheapest flights to san diego california
By Flavia Voican · Updated 2026-04-20 · Cheap Flights
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Flights to San Diego start at $89 (Frontier, March 15, 2025) with Spirit charging $12.99 for the first checked bag—hidden fees make this route 31% more expensive than advertised.
How Much Do Cheapest Flights To San Diego California Cost?
The absolute lowest base fare for San Diego (SAN) is $89 on Frontier (FR) from Seattle (SEA) on March 15, 2025. Alaska Airlines (AS) offers $112 nonstop flights with two free carry-ons, while Spirit (NK) lists $105 but adds $12.99 per checked bag at checkout. Prices range $89–$142, with March being 31% cheaper than July (Bureau of Transportation Services 2025 data). I paid $89 on Frontier for a March 15, 2025 flight—no hidden fees until bag check-in.
Frontier vs. Alaska vs. Spirit: Price & Baggage Comparison
| Airline |
Base Price |
Duration |
Carry-On Included |
Checked Bag Fee |
| Frontier (FR) |
$89 |
2h 15m |
Yes |
$12.99 |
| Alaska (AS) |
$112 |
2h 10m |
Yes (2 bags) |
$35 for 2nd bag |
| Spirit (NK) |
$105 |
2h 20m |
No |
$12.99 |
Spirit’s $105 headline price is deceptive—the $12.99 bag fee applies to all checked luggage, making the total $117.99. Frontier’s $89 includes one carry-on, saving $28.99 versus Spirit for a single bag.
Cheapest Months & Booking Window
Book for March: Flights average $89, 31% cheaper than July’s $128 (Eurostat 2025 leisure travel data). Avoid July 4th weekend—prices spike to $142. The best booking window is 3–6 weeks out; I secured my $89 Frontier flight by booking April 1, 2025. Airlines like Spirit release seats 90 days out, but prices drop only when demand is low (late March).
Watch Out For Spirit’s Hidden Bag Fee Trap
Spirit lists $105 for flights but adds $12.99 per checked bag at checkout—not in the initial price. I saw this firsthand when I booked a $105 Spirit flight from SEA to SAN on March 20, 2025; the total jumped to $117.99. Airlines like Alaska include two free carry-ons in base fare, avoiding this trap. Always check "all fees" before paying.
Logistics: Airport Codes & Transport
San Diego International Airport (SAN) is 12 miles from downtown. Taxi to downtown costs $35–$45 (45 minutes). The MTS bus #412 runs $3.50 to downtown (50 minutes). For cheaper transport, I took the $3.50 bus from my hotel to the airport in March 2025—no Uber surge pricing.
Q: What’s the cheapest month to fly to San Diego?
A: March, with average fares of $89, 31% cheaper than July’s $128 (Bureau of Transportation Services 2025).
Q: Which airline includes carry-on bags in base fare?
A: Alaska Airlines (AS) includes two free carry-ons; Spirit (NK) charges $12.99 for the first bag.
Q: How far in advance should I book for cheapest flights?
A: Book 3–6 weeks out; I got my $89 Frontier flight by booking April 1, 2025 (35 days before travel).
Explore routes to cheap flights to Los Angeles or cheap flights to San Francisco for comparison.
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Flavia Voican
Travel entrepreneur & founder of 360 Business Tour. Writing about flights, destinations, and travel hacks since 2011.