Frontier Airlines has been having some spectacular deals on their international routes lately. Prices are as low as $135 round-trip from a few US cities to Puerto Vallarta, Los Cabos, Cancun, and Punta Cana.

For example, we found seats departing Denver DEN on Saturday, March 3, returning from Puerto Vallarta PVR on Saturday, March 10.

Travel days vary slightly by route, but are generally for travel on Mondays, Tuesdays, Wednesdays, and Thursdays through early May with no advance purchase required. Some routes are not operated on a daily basis and/or may be seasonal ending in early April. Click on the fare details for more information on each route.

Nonstop fares include:

Denver to Puerto Vallarta $135 round-trip

Denver to Los Cabos $137 round-trip

Chicago to Cancun $166 round-trip

Denver to Cancun $166 round-trip

Philadelphia to Cancun $206 round-trip

Cleveland to Cancun $206 round-trip

Philadelphia to Punta Cana $230 round-trip

Cincinnati to Cancun $246 round-trip

St. Louis to Cancun $246 round-trip

Chicago to Puerto Vallarta $249 round-trip

Kansas City to Cancun $266 round-trip

Chicago to Punta Cana $270 round-trip

Chicago to Los Cabos $271 round-trip 

This sale is unadvertised and prices may jump at any moment. Keep in mind that Frontier charges extra for any bag larger than a small personal item (small backpack, purse, etc.). Pack a swimsuit and hit the beach. If you need to bring more, checked bags start at $25 each way.

Another option is to add The Works bundle when booking on FlyFrontier.com, which includes one checked bag, one standard sized carry-on bag, stretch seating, no change fees, and refundability. Adding The Works to our example from Denver to Puerto Vallarta brings the fare to $291 round-trip, which is still lower than the competition.