Twelve years have passed since Southwest’s first international flight took place. On July 1, 2014, the carrier inaugurated six routes: Atlanta to Aruba and Montego Bay; Baltimore to Aruba, Montego Bay, and Nassau; and Orlando to Montego Bay. Only the first two markets are no longer served.

In 2025, the US Department of Transportation shows that Southwest carried just over four million passengers internationally. That was its lowest traffic volume since 2023. Given the airline’s vast domestic operation, just 2.4% of its total passengers flew beyond the US last year. While the source shows that its domestic load factor was 77.3%, it filled 81.4% of its international seats. As always, it is all about how it is achieved.

This Route Had The Lowest Load Factor In 2025

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According to Cirium Diio data, Southwest had 70 scheduled international routes last year, although some only had limited flights. The carrier will begin a handful of extra international routes in spring 2026. Assuming a minimum of 1,000 round-trip passengers, the DOT indicates that Colorado Springs-Cancun had the lowest seat factor. This was Colorado Springs’ longest scheduled nonstop flight ever, but far from being among the carrier’s longest airport pairs.

The airline filled just 42.9% of the available seats between Colorado Springs and Cancun, and carried a minuscule 1,725 passengers. This was a shame, as it was Colorado Springs’ first (and only) international market. People seemed to prefer to fly to Denver for the much greater flexibility and choice.

With a Saturday-only flight, Colorado Springs-Cancun was served between June and August, with a handful of flights in November and December. Six round-trip services were available in early 2026, with the final departure on April 4. Unsurprisingly, the route, which covered 1,407 nautical miles (2,606 km) each way, is no longer scheduled or bookable.

Southwest’s Second To Fifth Least Popular Services

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Tampa to Havana was the carrier’s second-worst performing route in this sense. That’s despite being served since 2016. Just 53.9% of seats were filled in 2025, which the DOT indicates was the worst year on record. Of course, the usual caveat about load factor being only one metric applies. However, such a poor result speaks volumes.

Compared to 2024, capacity rose by 3.6% to 212,975, while traffic fell by 7.2% to 114,749. As such, the seat factor reduced too. No wonder Southwest said last year that US-Cuba flights have become unprofitable. To help remedy the situation, Southwest’s frequency on this route halved in September 2025, with a much more reasonable daily operation. Far fewer seats meant the load factor rose to a better but still insufficient 65.6% for the final few months of the year.

Kansas City-Montego Bay ranked third (60.4%; 1,163 passengers), followed by Atlanta-Cancun (63.8%; 11,755 passengers) and San Diego-Los Cabos (65.0%; 16,963 passengers). The route to Jamaica started in 2023, becoming the first time Kansas City ever had regular service to the Caribbean. Flights ceased in April 2025. While Atlanta-Cancun remains part of Southwest’s network in 2026, significantly fewer flights are now available.

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Rounding Out The Ten International Routes With The Lowest Loads

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In sixth place is Orange County-Puerto Vallarta (69.5%; 62,170 passengers), followed by Fort Lauderdale-Montego Bay (69.7%; 6,828 passengers), Cancun-New Orleans (70.9%; 5,511 passengers), Baltimore-Los Cabos (71.5%; 2,044 passengers), and Orlando-Grand Cayman (72.1%; 59,825 passengers).

Aside from having low loads, these four routes have something else in common. They all started in 2023. Only one of them won’t be served in 2026. That’s Fort Lauderdale-Montego Bay, with the last service taking place late last year, perhaps influenced by the consequences of Jamaica’s hurricane.

Between January 2023 and May 2024, Fort Lauderdale’s flights ran daily. But from June 2024, they only operated weekly. Despite the lack of capacity, it still only filled fewer than seven in ten seats. The DOT indicates that the other US airlines on the airport pair achieved low results too. Spirit filled 72.3% of its available seats, while JetBlue achieved 75.1%.

Just under half of Southwest’s passengers connected to another flight in Fort Lauderdale. For obvious reasons, the Florida airport is not among the carrier’s leading facilities for transfer traffic. Although the numbers were tiny, with just a few hundred passengers each, booking data shows that Nashville-Montego Bay, via Fort Lauderdale, was the leading segment. Chicago Midway was second, followed by Pittsburgh, St. Louis, and—most interestingly—San Juan. Flying San Juan-Fort Lauderdale-Montego Bay added twice the distance of a nonstop flight, but that’s moot, as they don’t exist.