Cheap Frontier Airlines flights Islip (ISP) to San Diego (SAN)

Scoring cheap one-way Frontier Airlines flights from ISP to SAN on Expedia couldn't be easier — just filter by "Price (lowest to highest)." Alternatively, check out our affordable round-trip fares for your next exciting vacation.**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.

For cheap Frontier Airlines fares from MacArthur Airport (ISP) to San Diego Intl. Airport (SAN), start searching one to three months before your intended departure. Reserving 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 influence the cost. Sunday is generally 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.

Sort your results by "Early Morning" and "Morning" to see the earliest flights from ISP to SAN. Setting off early means you're 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.

With a rewarding loyalty program, Frontier Airlines is a popular choice for many passengers flying from ISP to SAN. Plus, as a Frontier Miles and One Key™ member booking through Expedia, you can earn OneKeyCash™* on eligible flights along with your airline miles.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.