$140 Cheap Frontier Airlines flights Raleigh (RDU) to San Juan (SJU)

Scoring cheap one-way Frontier Airlines flights from RDU to SJU from $140 on Expedia couldn't be simpler — just filter by "Price (lowest to highest)." Alternatively, check out our affordable return fares from $265 for your next exciting 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.

Getting the best Frontier Airlines deals from RDU to SJU often comes down to booking at the right moment. You can save 17% on international flights when you book 18 to 29 days before takeoff instead of four to five months ahead. What's more, you can pocket 17% on average by buying your tickets on a Sunday rather than a Friday, which is usually the most expensive day to book.* It's smart to kick off your flight search about one month before you want to travel.*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.

Browse Frontier Airlines's earliest flights from RDU to SJU by checking our "Early Morning" and "Morning" filters. Not only will you get to your destination sooner, early departures also experience 20% fewer 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.

Fly from RDU to SJU with Frontier Airlines and you'll enjoy a range of benefits starting with a rewarding loyalty program. When you book through Expedia as a Frontier Miles and One Key™ member, you may also earn OneKeyCash™* to use on select future travel purchases.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.