snorkeling Punta Cana or Bayahibe
Punta Cana doesn't have really great snorkeling from the beach. Plus some areas have a lot of heavy, fast boat traffic so you must stay within the roped off swim zones. The northern Uvero Alto area and Hard Rock Hotel can often be too rough for snorkeling.
Expect fast boat traffic between the Majestics and the Barcelo Bavaros.
At Dreams Punta Cana in the north, on rare calmer days, you can snorkel around the coral that acts as a natural breakwater for the beach, head towards the left side of the beach where the watersports center and water trampoline are located. The water here is usually calmer. Same at Excellence to the right but pay attention to the swim/no swim flags, the current can be strong.
Ok snorkeling out front of Majestic Colonial inside the swim zone, follow rope to where it gets deeper.
Catalonia Bavaro & Catalonia Royal have the best snorkeling off the beach with calm water all year round and little to no boat traffic. They are in Cabeza de Toro where most of the snorkel tours go.
There are plenty of snorkel tours that go to the outer reefs. Ask at your watersports center or send me a private message and I'll recommend some.
Snorkeling gear at most hotels is free for 1 hour each day, first come first served, usually with a 20$US returnable deposit. Good idea to bring your own mask.
For great snorkeling in the DR go to Bayahibe, La Romana. Dreams La Romana has the best right off the beach, also good at Iberostar Hacienda. Plenty of snorkeling tours available to Saona & Catalina islands 30 mins speed boat ride away. (btw Gran Bahia Principe La Romana doesn't have good snorkeling, nearby river makes the water too murky).