A 63-year-old man was found in waters off Hanauma Bay, according to the Honolulu Emergency Services Department.
The incident happened shortly after 11:40 a.m. Thursday.
Officials say Ocean Safety lifeguards found the man under water.
Lifeguards brought the man to shore, where he was pronounced dead.
Ocean Safety officials believe the victim is a Korean visitor.
His identity has not been released at this time.