A high surf warning is posted for north and west shores of Kauai County, Oahu, Molokai and Maui.
Forecasters said a large northwest swell will build through the day on Saturday.
The warning is in effect from 6 a.m. Saturday to 6 p.m. Sunday. Surf along north shores is expected rise to about 22 to 28 feet. West shores could see surf of 15 to 20 feet.
“Expect ocean water occasionally sweeping across portions of beaches, very strong breaking waves and strong longshore and rip currents,” the weather service said. “Anyone entering the water could face significant injury or death.”