Southwest Airlines will launch Hawaii service from four airports in California, as it also confirms plans to move ahead with inter-island service.

The Dallas-based low-cost carrier will serve the Aloha state from Oakland, Sacramento, San Diego and San Jose. Last week, the airline announced it would fly to four airports in Hawaii: Honolulu, Kauai Lihue, Kona and Maui Kahului.

It did not reveal exact details on routes and frequencies, but reiterates that it plans to begin sales later this year pending regulatory approvals.

In an announcement in Hawaii earlier today, Southwest president Tom Nealon also confirms that the airline will "eventually" offer inter-island service "as operations ramp up initially across four airports in Hawaii", says the airline.

Southwest's entry into the Hawaii inter-island market will provide competition to Hawaiian Airlines, which dominates on service among the islands. The Honolulu-based carrier did not immediately respond to requests for comment.

Southwest will compete against Alaska Airlines and Hawaiian on service between the four airports in California and Hawaii, FlightGlobal schedules data show.

Alaska operates from Oakland, San Diego and San Jose to all four Hawaii airports that Southwest plans to serve. Seattle-based Alaska also flies from Sacramento to Maui.

Hawaiian operates from Oakland, San Diego and San Jose to Honolulu and Maui. It also serves Honolulu from Sacramento and plans to serve Kauai from Oakland in July.

Source: Cirium Dashboard