Police said a 43-year-old Utah man died after snorkeling at Sharks Cove in Pupukea.
Click here to watch Nana Ohkawa's report.
Just after 9:30 a.m. Sunday, Navy Corpsman Cory Butler was enjoying a day at the beach when he spotted a snorkeler waving for help at the shoreline.
"He was having trouble breathing. He was having a hard time talking. He just asked if I could help him get out of the water because he couldn't breathe, and that's when I asked for some more help," said Butler.
Butler said he then moved the snorkeler in distress up to shore and that's when he noticed the man was unresponsive.
"We had to start doing CPR on him so myself and another gentleman switched out and did CPR," said Butler.
Fire crews arrived within minutes and continued CPR. Responders said the snorkeler eventually regained a pulse and started to breathe. EMS transported him to the hospital in critical condition where police said he later died.
"If you have any signs or symptoms that you feel off, you want to listen to your body and instincts, and if you don't feel good that day I say to stay out of the water," said Capt. Greg Ikeda with the Honolulu Fire Department.
Fire officials said the man may have had a medical condition that contributed to his death.
It was low tide at Sharks Cove when the incident happened. HFD said no environmental factors led to his death.