South of Cancun and Xel-Ha, the snorkeling at Punta Solyman offers plentiful marine life. This is an ironshore line the typically requires calm seas for shore-access. It is known for surges from November through April. The 10 to 20 foot deep waters can be accessed from shore or by boat. While there is little coral growth, there is usually abundant reef fish.
To reach the snorkeling in Punta Solyman by air, you will need to fly into Cancun International Airport (Aeropuerto de Cancun - CUN). Some of the hotels provide shuttle vans or there are shuttle vans to be hired down to Punta Solyman. Renting a car to drive around can be hazardous do to the potential for unwarranted police stops resulting in required immediate cash payments. An alternative airport option is to fly into Aeropuerto Internacional de Cozumel (CZM) and take the ferry from Cozumel to Playa del Carmen. From there, you can take a much shorter shuttle van down to Punta Solyman.
Note: while snorkeling offshore here, keep in mind that from November through March you might encounter bull sharks right off the beach.
Overall, Punta Solyman is the 38th most popular snorkel dive spot of all 39 snorkeling dives in Mexico.