There is no diving, scuba or snorkeling in Volcan and Cerro Punta, which is located in the mountains, about an hour or so from the Pacific Ocean.
There are, however, several options fairly close by to Volcan and Cerro Punta if you want to go scuba diving or snorkeling. For the closest one, you may go to David, which is about a one hour drive away, and find several areas where you can go snorkeling. If you drive to Boca Chica, there are hotels that make arrangements for diving, scuba or snorkeling. If you have a boat you may go to Paridas, which is a beautiful place to dive, scuba or snorkel.