Save 20% on Flights to Hawaii as Booking Deadline Hits

There’s a real but short-lived airfare discount on Hawaii flights right now, and it disappears at the end of New Year’s Eve.

Using promo code THANKYOU20, travelers can get up to 20% off mainland–Hawaii flights booked through Alaska’s system, including flights operated by Hawaiian Airlines and interisland. Travel runs from early January through late May 2026, after which Hawaii pricing usually starts tightening again for summer.

This is not an interisland sale, even though interisland flights are included. The far bigger value is on longer mainland routes, where a 20% discount on the base fare can actually move the needle, especially if you’re booking more than one traveler.

The Hawaii discount rules are not intuitive.

The discount depends on both direction and departure day. And the rules are asymmetrical.

Flights to Hawaii get the full 20% discount when departing Sunday through Wednesday. Flights from Hawaii get the full 20% discount when departing Tuesday through Friday. On all other departure days for Hawaii routes, the discount drops to 10%, even though you’re using the same promo code.

For interisland flights, departures are Monday through Thursday.

That split in pricing matters because a midweek outbound paired with a weekend return can price differently than anticipated, and that adds up quickly. Shifting a return by a day can make the difference towards a more noticeable discount.

Hawaiian Airlines flights qualify.

Although the booking is made through Alaska Airlines, Hawaiian Airlines flights to and from Hawaii are included under the same rules. That significantly expands the pool of available flights, particularly on routes where Hawaiian’s schedules or aircraft availability are better.

Booking deadline and Hawaii travel window.

The promo code must be used by December 31 at 11:59 p.m. Pacific Time. Travel is valid from January 7 through May 21, 2026, with blackout periods around mid-January, Presidents Day week, and peak spring travel dates. See official rules on the Alaska website.

As usual, the discount applies only to base fares and not to taxes or fees, and some fare types won’t qualify. Not every flight will price the same way, and some dates will disappear faster than others.

If you’re already booking a trip to Hawaii for early 2026, this is worth checking before the deadline hits. If you’re not, it’s probably not reason enough to plan a trip around it.

Would you shift your Hawaii travel plans for the extra 20%?

Photo Credit: Beat of Hawaii at Mauka Terminal at HNL.