The boys, who were age 16 and 17, were on a scuba expedition with seventeen other divers at about 11:30 a.m., deputies said.
The group couldn't locate the boys once everyone swam to the service, so multiple rescue teams were dispatched in search of the teenagers.
The two victims were found not long after the search began, and they were taken in an ambulance to a local hospital, where they were pronounced dead, deputies said.
An autopsy will be performed Monday.
No other injuries were reported.