Puerto Morelos

Puerto Morelos is a sleepy fishing town that is a great day trip from Cancun.  For around $20 you can go with a guide out to the reef. The coral is terrific and you will see some outstanding fish: trumpet fish, blowfish, barracuda, cow fish, etc. After snorkeling you can get a nice meal at one of the restaurants in town. Definitely a highlight for your trip and you'll likely be going back in your next trip.