Southwest Airlines is finally on its way to Hawaii.

The Federal Aviation Administration on Wednesday approved the low-cost carrier to fly to the islands from the West Coast, Southwest said.

The airline, which will service Hawaii from several cities in California, will announce when it will start selling tickets to the popular vacation destination in the coming days, it said in a statement.

The low-cost airline has been eagerly waiting for regulators to clear it to fly to the islands, which are a big part of its growth plan this year.

The approval comes as Southwest is locked in a bitter dispute with its mechanics' union after a surge in out-of-service planes due to mechanical issues that have grounded dozens of jets. The airline and its mechanics have been negotiating a contract for more than six years and the some 2,400 in-house mechanics seek bigger pay raises that what the company has proposed.

Southwest revealed its plan to start flying to Hawaii in October 2017, with an eye on selling tickets by 2018, but the partial government shutdown delayed those plans.

The airline needed the FAA to sign off on its plans to fly Boeing 737-800 jets over water for long distances. Safety inspectors had been flying with Southwest to Honolulu from Oakland, Calif. in recent weeks and met with airline executives to review Southwest's navigation, maintenance and other procedures.

The airline's decision to offer service to the Aloha State could make Hawaiian vacations cheaper. In markets where the airline has nonstop service, average one-way fares are $45 lower than in cities without those routes in what's been dubbed the "Southwest Effect," a University of Virginia study found.

Southwest plans to fly to the islands from four California cities: Oakland, San Diego, San Jose and Sacramento and fly to Honolulu, Kahului on Maui, Kona, and Lihue on Kauai. The airline also intends to offer service between the islands.

Southwest plans to grow its flying 5 percent this year, and half of that will come from Hawaii, the airline said last month.

That growth comes at the expense of expanding to some international destinations.

"Were it not for Hawaii, we would absolutely be adding some more international routes and augmenting some of our flying," Southwest CEO Gary Kelly told analysts on an earnings call in January. "So it's simply a matter of prioritization, and Hawaii, I think, deserves that kind of prioritization. It's that big of an opportunity."

Southwest shares were little changed postmarket trading. Shares of Hawaiian Holdings, parent of competitor Hawaiian Airlines, were also flat.