Surf along north shores of Oahu, Kauai County, Maui and Molokai is expected to continue in the 12- to 18-foot range Sunday, declining to 10- to 15-feet Sunday night and then 8- to 12-feet Monday.
A high surf advisory is in effect until 6 p.m. Sunday night.
The National Weather Service says strong, breaking waves will create significant shore break and strong rip currents, making swimming dangerous.
Forecasters advise beach-goers to heed advice from lifeguards and use caution near the surf.
The waves are big and consistent enough for the start of the Billabong Pipe Masters in Memory of Andy Irons contest at Ehukai Beach.
The first two rounds of the competition are taking place Sunday morning and afternoon.