Frontier Airlines Top 20 Busiest global Routes in 2025

Frontier Airlines (F9), with its low-cost carrier model and attractively painted animal-themed planes, has established a steadily growing worldwide presence out of the United States. While its domestic route network remains its core business, Frontier’s international routes, especially to Mexico and the Caribbean, reflect increasing demand from value-seekers heading to sunny destinations.

This article analyzes Frontier Airlines’ 20 busiest international routes by frequency per month, seats, and available seat miles (ASMs), and defines the hubs, trends, and geographic patterns determining its international footprint.

Photo: Clément Alloing

San Juan Connections Boom

Frontier’s two busiest international routes both originate out of San Juan (SJU), Puerto Rico, and both are to popular Dominican Republic destinations. The busiest of the bunch is the Punta Cana to San Juan route, which sees a frequency of 82 monthly flights and over 17,800 seats.

On its heels is the San Juan to Santo Domingo route with 79 flights and nearly 16,500 seats per month. Together, they contribute to Frontier’s activity in short-haul leisure connections in the Caribbean basin between Puerto Rico and the Dominican Republic.

The frequency levels also suggest that the routes are profitable as well as serve both the VFR (visiting friends and relatives) and leisure markets.

Photo: Frontier Airlines

O’Hare Serving as a Key Gateway

Chicago O’Hare (ORD) is one of Frontier’s pillars of its global strategy. The airline has numerous high-volume routes from this massive Midwestern hub. ORD–Punta Cana ranks third in Frontier’s international network with 62 monthly departures and nearly 15,000 seats. It is among Frontier’s highest-margin international flights, with a whopping 29.4 million ASMs produced by this long-haul vacation flight.

Chicago also has strong connectivity to Cancun with 62 monthly flights and over 13,000 seats. Cancun is still the destination of choice for most U.S. low-cost carriers, and Frontier is not an exception. Frontier also serves Punta Cana out of St. Louis (STL) and Cleveland (CLE), indicating its attempts at serving sun-and-sand areas out of secondary Midwestern cities.

Photo: By Tomás Del Coro from Las Vegas, Nevada, USA – N233FR Frontier Airlines Airbus A320-214 s/n 7095 “Buck The Pronghorn”, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=71324274

Cancun at the Center

Cancun (CUN) is Frontier’s best-international-connected airport in its system, with a presence on eight of the top 20 routes. Cancun attracts price-conscious U.S. travelers and families seeking bargain international vacations. Frontier connects Cancun to a wide swath of the U.S., including Chicago, Denver, Philadelphia, St. Louis, Atlanta, Dallas/Fort Worth, Houston, Miami, Cleveland, and Cincinnati.

Of these, Cancun–Philadelphia is the busiest one in terms of capacity with 62 monthly flights and nearly 14,500 seats. Its ASM value is over 21 million, which indicates it is a longer and scheduled route for the airline.

Photo: N943FR Frontier Airlines 2005 Airbus A319-112 – cn 2518 “C… | Flickr

Atlanta’s Caribbean Reach

Atlanta (ATL), while dominated by legacy carrier Delta Air Lines, has discovered a niche for Frontier’s low-fare service to the Caribbean. The airline operates ATL to Montego Bay, Punta Cana, and Cancun, which suggests that Frontier is not afraid to take on Delta in high price elasticity markets.

The Atlanta–Montego Bay route sees 58 flights a month with more than 11,200 seats on offer. Punta Cana receives 44 monthly flights out of ATL, with Cancun receiving regular flights as well. These routes have moderate frequencies with respectable ASM contributions. The ATL–Punta Cana route, for instance, generates more than 11.7 million ASMs, thus proving the viability of medium-haul international service out of one of America’s most crowded hubs.

Florida’s Modest Role

Despite being headquartered in Denver, Frontier has a growing footprint in Florida, particularly in Miami (MIA). While its Florida–Caribbean route system is not as comprehensive as Spirit’s or JetBlue’s, Frontier nonetheless sees substantial traffic from Miami to Punta Cana and Cancun.

Miami–Punta Cana and Cancun–Miami are both among the top 20, albeit at reduced frequencies (28 flights a month each). These routes are used to feed largely South Florida’s wide Latino diaspora and strong leisure travel market. While Miami is usually an expensive airport for ultra-low-cost airlines, Frontier’s presence here illustrates the carrier’s readiness to disrupt existing players and benefit from Florida’s deep pool of demand.

In addition to its Chicago base, Frontier is expanding international service from other Midwestern airports like Cleveland and St. Louis. Cancun–Cleveland on 44 monthly frequencies with over 10,000 seats attests to high demand for travel from the Rust Belt to Mexican shores. Punta Cana is similarly offered from Cleveland and St. Louis, though less frequently.

Photo: Cado Photo

Short-Haul Curiosities

Despite having lower frequencies, some of the routes are still in the top 20, such as Cancun to Miami or San Juan to Santiago. These routes make up for dense frequency and steady demand. San Juan–Santiago, with only 24 flights and fewer than 4,500 seats a month, still falls in the top 20.

Similarly, Cancun–Miami, boasting a meager 28 flights and 5,208 seats a month, ranks in 17th place. These cities give Frontier access to budget-minded travelers who may not have as much international flight availability.

By flying from secondary airports to warm international destinations, Frontier reduces operating costs while offering customers inexpensive international options outside of major coastal gateways.

Bottom Line

Frontier Airlines’ international network may not be as expansive as the majors, but it’s leisure-focused. From Cancun and Punta Cana to San Juan and Santo Domingo, the carrier targets short-to-mid-haul leisure destinations where demand is strong, predictable, and price-sensitive.

By connecting these high-demand markets with low-fare, high-frequency service from multiple U.S. cities, especially in the Midwest and Southeast, Frontier maximizes its Airbus A320neo fleet efficiency.

And with more international slots and longer-range aircraft likely coming in the years ahead, Frontier’s top 20 international routes today may only be the start of its broader global ambitions.

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