The U.S. Coast Guard received a report at 5:50 a.m. that four men who had set out from the Richmond Marina in a 25-foot pleasure craft had crashed into some rocks.
One man had reportedly fallen overboard after the crash.
The Coast Guard sent a boat to the area and a rescue team pulled the man from the water and administered CPR, Petty Officer Levi Read said.
The man, identified by the Contra Costa County coroner's office as 61-year-old Richmond resident Roland Reed, was taken to the Kaiser Permanente Richmond Medical Center, where he was pronounced dead.
Nobody else on board was hurt, Read said.