Authorities said Mark Cross told his family on Wednesday that he was going out on his kayak for a few hours, but he never returned.
Helicopters and patrol boats, along with the Orange County Sheriff's Department, began looking for Cross on Thursday. So far, they haven't found him or his kayak.
A family member told the Coast Guard that he almost never wears a life jacket when he goes out on his kayak.
"He is an experienced boater. He has done outrig canoeing before," said Lt. Anastacia Thorsson of the U.S. Coast Guard.