Frontier Airlines Flash Sale: Flights From $38 Round-Trip [Book by August 21]

Frontier Airlines, the Denver-based low-cost carrier, is offering some super-cheap fares, starting at $38 round-trip, but you’ll need to book quickly.

The latest flash sale offers cheap flights across the U.S., the Caribbean, and Latin America — for those who move fast, anyway. You’ll need to book by August 21 and travel in the month of September.

Here’s what you need to know to save big on your next Frontier flight!

Frontier Airlines Sale — Details

When booked by August 21, Frontier Airlines is offering flights from $38 round-trip.

Eligible travel dates in this offer are September 2 to September 30, 2025. You’ll need to purchase at least 14 days in advance, and you must make a round-trip booking — despite the fact some of the promotional materials for this offer are discussing $19 one-way fares.

The promotion’s terms say not all routes are available on all dates, but there are no specifics available. Thus, playing around with dates — and having some flexibility — might be needed.

There’s no promo code required for this offer.

Sample Fare

To benefit from this promotion, customers can book travel at FlyFrontier.com or the Frontier mobile app (iOS, Android) by August 21, 2025. A 14-day advance purchase is required to qualify for the promotion. 

For instance, we priced out this round-trip booking from Atlanta (ATL) to Washington, D.C. (IAD). The cheapest fares require a Discount Den membership, dropping the price from $90 to $48.98 in this example.

When you calculate your Frontier airfare for this promotion, keep in mind that certain services, such as checking baggage and priority boarding, are not included in the base rate and will incur additional fees. Many of those can be avoided by having elite status with Frontier, though.

Final Thoughts

Frontier Airlines is offering round-trip flights from $38 if you book soon. You’ll need to book by August 21 and travel from September 2 to September 30, 2025. Booking this quickly and traveling next month won’t work for everyone, but it’s a great deal for those who can take advantage of it.

Not all routes are available for $38 round-trip, though. The cheapest prices will be available on short flights and for those with a Discount Den membership. If you’re flying further and don’t travel with Frontier often enough to justify paying for a Discount Den plan, it’s worth checking Frontier’s price against what other airlines are charging, since this sale might not be the best option.