Book fast! Frontier is having a promo code sale valid for purchase through today. Save 75% off the base fare for travel through May 23. Fares start at just $39 round-trip.

Use promo code SAVE75 when booking on to take 75% off the base fare for nonstop domestic flights. Travel is valid on Mondays, Tuesdays, Wednesdays, Thursdays, and Saturdays, from April 24 through May 23.

The discount does not apply to taxes nor Frontier's online booking fee, which they label a "Carrier Interface Charge". This means some routes still won't have a very big price drop even with the big sticker shock of 75% off. However, there are plenty of routes where we are seeing very large discounts so you may be able to save big.

There is a long list of specific routes excluded from the promo code sale. Frontier operates about half of their markets on limited days each week. Click on the fare details for more info.

Tickets must be booked by 11:59pm ET, on April 23.

A sample of nonstop fares include:

Detroit to Long Island-Islip $39 round-trip

Denver to Las Vegas $42 round-trip

Salt Lake City to Las Vegas $51 round-trip

Grand Rapids to Philadelphia $51 round-trip

Las Vegas to San Jose, CA $53 round-trip

Indianapolis to Austin $56 round-trip

Denver to Seattle $69 round-trip

Raleigh to Houston $69 round-trip

Cincinnati to Orlando $72 round-trip

Columbus to Austin $74 round-trip

Philadelphia to Nashville $77 round-trip

Seattle to Cleveland $78 round-trip

Tampa to Las Vegas $79 round-trip

St. Louis to Denver $79 round-trip

Providence to Tampa $84 round-trip

Chicago to Las Vegas $84 round-trip

Indianapolis to Orlando $85 round-trip

Denver to Washington DC-Dulles $89 round-trip

New York to Denver $89 round-trip

Austin to San Diego $96 round-trip

Atlanta to San Juan $106 round-trip

Many more routes are available and these fares all work in reverse as well. Lowest fares may not be available throughout the entire travel period. Check our pages for all flights to DenverLas Vegas, OrlandoTampaPhiladelphia, Cleveland, Austin, Raleigh, and San Jose to see more of today's finds. This is not a full list of Frontier cities, so check flights from your city to see what's available.

Keep in mind that Frontier charges extra for any bags larger than a small personal item (small backpack, large purse, etc.). Pack super light to get the lowest price. Checked bag fees start at $25 each way. Larger carry-on bag fees start at $30 each way.

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