The National Weather Service has issued a high surf advisory for all north- and west-facing shores on Oahu, Kauai and Niihau, along with north-facing shores on Maui and Molokai, and west-facing shores on Hawaii island.
The advisory is in effect until 6 a.m. Wednesday.
Just before 4 p.m. today, the NWS said a north-northwest swell was building off Hawaii and would continue to strengthen overnight before peaking on Tuesday through Thursday and slowly lowering on Friday.
A significant westerly component of the swell could lead to potential warning level surf heights on Tuesday night.
Forecasters say surf will build up to 15 to 20 feet along north-facing shores and 10 to 15 feet along west-facing shores.
Beachgoers, surfers and swimmers should heed all advice given by lifeguards and exercise caution when entering the ocean.