Punta Cana is on the east coast - Atlantic side, south coast Bayahibe / Dominicus (La Romana area) is by Caribbean sea. Diving conditions around Punta Cana are not as good as around Bayahibe, all divers will tell you if you want to come for a diving vacation don't go to Punta Cana. You can check the area and the resorts at Discover Bayahibe