Wasatch County Fire said the woman was in a diving certification class when she experienced a medical emergency in the water.
Emergency crews performed CPR, she was flown to the University of Utah Hospital and died that evening.
Her identity has not yet been released and the medical examiner is working to determine her cause of death.
The Utah Crater is a natural hot spring with an average water temperature of about 95 degrees year-round. Its deepest point is 65 feet.
