The interisland price war has begun.

Hawaiian Airlines dropped airfares Monday to as low as $98 for round-trip flights between Oahu and Maui starting in April as competition from Southwest disrupts the interisland market — at least temporarily.

While air prices vary daily — and sometimes hour by hour — Hawaiian was listing round-trip fares at $98 for most days in May as of Monday afternoon, matching Southwest’s lowest price of $97.60. Southwest begins its interisland service at the end of April.

“This temporary fix of a price war is crazy,” said Lahaina resident Enoka DelaCruz. “But is the availability really there? How long is it good for? Is it long term into the year 2020, or is it just for three months that we’re going to have this quick fix to allow the local residents of Hawaii to travel within the islands?”

DelaCruz said if the low prices continue, “then I would definitely be encouraged to travel more.”

No one knows how long the low fares will last, and consumers must be flexible to scoop up the deals, said Honolulu travel agent Sally Asao.

“This is the cheapest I’ve ever seen it in a long time. When fares drop like that, by the time you’re ready to book, they’re all gone. Maybe out of 150 seats, 30 are the lowest fare. It’s first come, first served,” she said. “It’s like if you book hotel kamaaina rates, once they’re gone you have to pay the rack rate or the next available rate. Once Southwest brings their prices up, (Hawaiian is) going to bring their prices up, too.”

Southwest initially kicked off its Hawaii service with introductory fares — trans-Pacific flights for as little as $49 each way and interisland sales from $29. Some sold out within minutes, and many were gone by the time Hawaii residents got word of the deals.

Southwest enters Hawaii with strong incentives for kamaaina travel: two free bags and no change fees for interisland flights. Hawaiian charges $25 for the first bag and $35 for the second bag and a $30 change fee plus the difference in fare.

Southwest’s isle debut is Sunday with a sold-out flight between Oakland, Calif., International Airport and Daniel K. Inouye International Airport. Service between Oakland and Maui begins April 7. The carrier will begin flying between San Jose, Calif., and Honolulu on May 5, with service between San Jose and Maui starting May 26.

Interisland service between Honolulu and Kahului begins April 28, four times daily in each direction. The carrier will begin service between Honolulu and Kona on May 12, flying four times daily in each direction.

”Southwest is just getting started in Hawaii, and the months of flying that sold out before our first service even arrives indicates an appetite for value in air transportation between the mainland and the state, as well as among the islands,” said Southwest spokesman Brad Hawkins. “Hawaii has a hometown carrier that is established, celebrated and enjoys great loyalty for the community service it provides. We’re entering both of those marketplaces to provide an alternative — a different experience.”

Hawkins said Southwest “consistently lowers average fares flown while growing the numbers of people flying” in the cities it serves.

Hawaiian spokesman Alex Da Silva said fares fluctuate daily and seasonally in the airline industry.

“We strive to offer our guests the greatest value through competitive pricing year-round, our unmatched neighbor island frequency and schedule averaging more than 170 daily flights,” he said.

Hawaiian has had a monopoly in the interisland market since the November 2017 bankruptcy of Island Air. The tough interisland market also saw the demise of Aloha Airlines in 2008 after a prolonged fare war and go!, which ended Hawaii operations in 2014.

It remains to be seen how long air prices will remain low.

“Southwest cannot fly for that price (long term),” Asao said. “They’re not making money. You can only do it for so long, and then they either got to stop coming here or they’re going to raise their prices. I don’t know how much money Southwest is putting into Hawaii, but I know Hawaiian has plenty of money.”

SOUTHWEST ROUTES

Southwest will kick off its Hawaii service on Sunday before expanding. The initial routes and start dates for mainland and interisland service:

>> Oakland, Calif., and Honolulu, Sunday

>> Oakland and Kahului, April 7

>> San Jose, Calif., and Honolulu, May 5

>> San Jose and Kahului, May 26

>> Honolulu and Kahului, April 28 (four round trips daily)

>> Honolulu and Kona, May 12 (four round trips daily)

>> Oakland and Kona, May 12 (connecting via Honolulu)

>> San Jose and Kona, May 12 (connecting via Honolulu)

>> Service announcements are expected for San Diego, Sacramento, Calif., and Lihue in the coming weeks.