Southwest Airlines announced Thursday that it is ramping up service in and out of San Diego in anticipation of the airport’s new and much larger Terminal 1, which will make its debut late next month.

Not only is the airline resuming service to several destinations it discontinued over the last few years — like Maui —  but it’s also expanding the frequency of a number of nonstop routes it already flies.

While most of the changes won’t take effect March 5, the announcement is a sign that Southwest, which is San Diego’s single largest carrier in terms of departures and passengers carried, is responding to the imminent debut of the mega Terminal 1 project.

The opening next month marks the completion of Phase 1, which will have the same number of gates as the existing terminal — 19 — but far more space. The initial phase of the new facility will occupy 940,000 square feet, more than three times the size of the existing terminal, which is 274,164 square feet. Because of construction the past few years, only 14 of the 19 gates have been in use in Terminal 1, airport spokesperson Jonathan Heller said.

In early 2028, the second phase, which will add 11 more gates, will be fully complete.

“Our San Diego customers patiently have anticipated this experience that will showcase our friendly customer service in the airport’s most modern and comfortable space, the new T1,” said Andrew Watterson, chief operating officer for Southwest Airlines. “For Southwest, more breathing room in a new facility with additional gates allows us to provide even more relevant air service as the perennially largest and most recognized airline in San Diego and in the state of California.

“New seasonal and year-round flights are as much an expression of our loyalty to serving San Diegans, as they are an acknowledgement of the relevance and appreciation for Southwest and our people.”

Based on information provided by Southwest and the San Diego airport, returning flights, which are now available for booking, include the following:

  • Spokane: This flight is returning weekends only. Southwest last flew there in 2020.
  • Maui: It’s returning daily and was last flown in 2022.
  • Puerto Vallarta: It will return five times a week and was last flown in 2020.
  • Seattle: Returning daily; last flown in 2020.
  • Bozeman: This will be spring break seasonal service available only on Saturdays. Southwest last flew here in 2022.

In addition, Southwest is expanding the frequency of already existing nonstop flights. Those destinations include:

  • Nashville, which will increase from three flights a day to four on Mondays, Thursdays and Fridays.
  • Boise, which is going from one daily flight to two on Mondays Thursdays and Fridays.
  • Eugene, which will expand to five times a week.
  • Orlando, which will increase to two flights a day.
  • Chicago-Midway, which will increase from three to four times a day.
  • Portland, which will increase to one daily flight.