These $39 round-trip fares from Frontier have been sticking around for a couple weeks. Certain routes come and go with each sale and seats are starting to sell out at these rock bottom prices. Today, around 50 routes are priced at just $39 round-trip and there are another 100+ routes priced under $84 round-trip with their 75% off* (base fare) promo code.

Availability is limited so you must be somewhat flexible to find the lowest price. Travel days will vary by route. Many routes start service the second week of April and have limited frequencies so be sure to check out the specifics in the fare details on your route.

The $39 round-trip fares are not advertised with an expiration date so they may jump in price at any time. Travel is valid on select dates through May 16. If you use the promo code listed below, you may be able to knock $1 off each way for Monday through Thursday travel, but these fares are available more days/week without the promo code.

A sample of nonstop $39 round-trip fares include:

Charleston to Philadelphia $39 round-trip

Atlanta to Cincinnati $$39 round-trip

Grand Rapids to Philadelphia $39 round-trip

Raleigh to Orlando $39 round-trip

Philadelphia to Milwaukee $39 round-trip

Buffalo to Raleigh $39 round-trip

Long Island-Islip to Detroit $39 round-trip

Birmingham to Orlando $39 round-trip

Providence to Austin $39 round-trip

Minneapolis to Colorado Springs $39 round-trip

Frontier also has a promo code valid for travel on Mondays, Tuesdays, Wednesdays, and Thursdays, from April 4 through May 23. Using the promo code SAVE75 on will discount 75% off the base fare for nonstop domestic flights within those specific dates.

Many routes may only be operated on limited days each week. If you want to piece together an itinerary flying only one-way on Frontier, you can use this promo code for one-way flights as well. Promo code expires at 11:59pm ET, tonight, April 2.

A sample of nonstop promo code fares include:

Colorado Springs to San Antonio $51 round-trip

Cincinnati to Jacksonville $53 round-trip

Tulsa to Washington D.C. $56 round-trip

Detroit to Austin $58 round-trip

Providence to Denver $66 round-trip

Trenton to Charlotte $68 round-trip

St. Louis to Orlando $74 round-trip

Dallas to Cincinnati $74 round-trip

Tampa to Las Vegas $79 round-trip

Cleveland to Portland $80 round-trip

Seattle to Cleveland $82 round-trip

Austin to San Jose $84 round-trip

Denver to Columbus $89 round-trip

Denver to Miami $92 round-trip

Atlanta to Los Angeles $99 round-trip

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, but most will. As always, Frontier has a long list of specific routes that are excluded from the promo code sale. 

These fares all work in reverse and there are many more routes priced under $99 round-trip as well. Check what's available from your city. Keep in mind that Frontier charges extra for any bags larger than a small personal item (small backpack, purse, etc.). Pack super light to get the lowest price. Checked bag fees start at $25 each way.

Above image by Colin A. Pierce via Shutterstock.

All products and services mentioned on Airfarewatchdog are independently selected by our team of expert travelers. If you buy something through our links, we may earn an affiliate commission.

More Stories You'll Love