Southwest Airlines is the US’ fourth-largest airline by available flights. In the first half of 2026, Cirium Diio data shows that it has about 3,900 daily flights. Its offering is flat year-over-year.

The carrier, which is increasingly evolving, plans 916 routes in the first six months of the year, which is based on having at least four departures. Some 834 links are domestic and 82 are international. Two new routes started in the first week of February.

Southwest’s Nine Longest Flights In 2026

Credit: GCMap

The order is based on the maximum block time, which is measured as chocks-off-to-chocks-on. While seven of the nine entries involve Hawaii, as would be expected, it is especially good to see two continental US services.

At a high of 6h 20m, Baltimore to San Francisco is the airline’s joint-longest service within the Lower 48. Southwest began this long route less than a year ago, in January 2025. It replaced Baltimore to Oakland, which existed until 2024.

You might wonder why only nine city pairs are listed. That’s simply because multiple other markets are scheduled at 6h 15m, so there would be too many to fit in. They include Los Angeles to Honolulu, Baltimore to Los Angeles, and Boston to San Francisco.

Phoenix To Honolulu Is Southwest’s Longest-Ever Service

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Analysis of all the carrier’s scheduled flights in the past decade shows that no route has ever exceeded seven hours. Until now. Phoenix to Honolulu is timed at up to 7h 5m this year, but this figure is only available on three dates: February 14, 21, and 28. The schedule for Valentine’s Day is shown below.

Otherwise, that long route’s maximum scheduled time in 2026 is 7h. That duration has been available on one other route in the past: Phoenix to Lihue. However, that market only operated between September 2021 and June 2022, amid the worst of the pandemic.

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Southwest Between Arizona And The Big Pineapple

Credit: Flightradar24

The carrier has operated between Phoenix and Honolulu since June 2021. For the most part, flights have operated daily. However, two daily services were available at times, most recently in April 2025. Southwest competes directly with American and Alaska/Hawaiian.

According to US Department of Transportation data for November 2024 to October 2025, Southwest carried 130,064 round-trip passengers on its nonstop flights. The same source suggests that only 26% of these passengers—33,957—were local. They only flew between the two airports; they didn’t connect elsewhere.

This means that most people—96,647—transited to another flight. Obviously, almost everyone did so in Phoenix, which is Southwest’s fourth-busiest airport by flights. Honolulu’s top segments via Phoenix were Dallas Love, Austin, Colorado Springs, Kansas City, and St. Louis.

In the 12 months to October, Southwest’s seat load factor on this route was 94.0%. It was substantially above its Phoenix average (78.4%), and exceeded its Honolulu average (88.5%). It was, in this sense, the airline’s second-best route from both cities. Of course, the load factor is just one performance measure, and should not be considered in isolation.