$140 Cheap Delta flights San Diego (SAN) to Helena (HLN)

Scoring cheap one-way Delta Air Lines flights from SAN to HLN from $140 on Expedia is a cinch --- just filter by "Price (lowest to highest)." Alternatively, check out our budget-friendly round-trip fares from $279 for your next getaway.**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.

Begin your search one to three months ahead of your departure date to get cheaper fares on Delta Air Lines flights from San Diego Intl. Airport (SAN) to Helena Regional Airport (HLN). You can save 25% by booking your domestic flight 34 to 86 days in advance compared to last-minute reservations made 6 to 12 days out. You could also reduce costs by buying your fare on a Sunday, as it's 6% cheaper on average than a Monday, the most expensive day to book.* Time it well, and you can enjoy significant savings on domestic trips.*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.

Filter your results by "Early Morning" and "Morning" to find the earliest flights from SAN to HLN. Heading off early means you're 20% less likely to experience cancellations.**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.

Offering a rewarding loyalty program and an excellent in-flight experience, Delta Air Lines is a favorite for many passengers heading from SAN to HLN. Plus, if you're a Delta SkyMiles and One Key™ member booking with Expedia, you could earn OneKeyCash™* on eligible flights on top of your airline miles, which can be put toward future getaways.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.