$129 Cheap Delta flights St. Louis (STL) to San Diego (SAN)

Scoring cheap one-way Delta Air Lines flights from STL to SAN from $129 on Expedia couldn’t be easier — just filter by “Price (lowest to highest).” Alternatively, check out our affordable round-trip fares from $257 for your next adventure.**These prices were available on Expedia within the past 7 days, for flights departing within the next year. Prices and availability are subject to change. Additional terms apply.

Look for one-way or round-trip flights to San Diego in January or November. You could find an affordable fare with Delta Air Lines during these off-peak months.

To find cheap Delta Air Lines fares from Lambert-St. Louis Intl. Airport (STL) to San Diego Intl. Airport (SAN), start searching one to three months before your intended departure. Securing domestic flights 34 to 86 days in advance could save you 25% compared to booking just 6 to 12 days ahead. The day you book can also impact the overall price. Sunday is usually the most affordable, while Monday is often the most expensive for domestic flights. You can save 6% on average by choosing to book on a Sunday.**Ideal booking window recommendation is based on average round-trip ticket prices for January through November for 2024. Best day of the week to book recommendation is based on average round-trip ticket prices for January through October 2024. All data sourced from ARC’s global airline sales database.

To see if there’s a direct journey from STL to SAN with Delta Air Lines or another carrier, use our “Nonstop” filter when browsing for flights.

Sort your results by “Early Morning” and “Morning” to browse the earliest departures from STL to SAN. Heading off early means flight cancellations are less likely.**Most reliable time of the day recommendation is based on January through August 2024 flight status data sourced from OAG’s global flight data platform.

San Diego Intl. Airport (SAN) is the primary San Diego hub for Delta Air Lines flights from Lambert-St. Louis Intl. Airport (STL).

Delta Air Lines makes traveling from STL to SAN more enjoyable with a rewarding loyalty program and an excellent in-flight experience. You could even start earning points with Delta SkyMiles. Remember to sign up to Expedia’s free One Key™ rewards program to earn OneKeyCash™*, which can be redeemed on future bookings.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.

Changes are typically free within 24 hours of making your booking, but your airline may add a charge after that time. For further details about modifying your reservation, go to your “Trips,” select your flight and click on “Manage Booking.” If you want the flexibility to make changes without extra charges, check the “Changes included” and “No cancel fee” filters when organizing your next trip.