Price wars continue to tamp down prices on flights from the mainland US to Hawaii. Fares have once again dropped, and you can dig up round-trip tickets for as little as $353 out of 26 different US cities.
The sale prices can be found with airlines like Hawaiian, Delta, American, and United through Google Flights. The time frame for the cheapest flights varies by departure city, but you'll find deals from June all the way into 2019, with the majority of deals appearing between late August and November.
Flights to Honolulu, Kauai, Kona, and Maui (cheapest destination depends on the departure city) can be found flying out of Atlanta, Billings, Boise, Dallas, Denver, Detroit, Houston, Milwaukee, Minneapolis, Missoula, Nashville, New Orleans, New York, Newark, Oakland, Orlando, Phoenix, Portland, Reno, Sacramento, San Francisco, San Diego, San Jose, Salt Lake City, Spokane, and Washington D.C., as highlighted by Scott's Cheap Flights.
However, you should move quickly if you want the best prices. The tickets are likely to go fast.