Hawaii island fire officials said a man apparently nearly drowned while swimming at an upper pond at Boiling Pots in Wailuku River State Park.
The man had been struggling while swimming across the pond in Hilo, fire officials said.
Two fire rescue divers were deployed into the pond by helicopter and found the man underwater.
The man was transferred by helicopter in critical condition to medics, who transported him to the Hilo Medical Center.
Fire officials got the call at 5:10 p.m. and were on scene at 5:17 p.m.