Cancun
 

Should I bring my snorkel equipment to Cancun? Best beaches?

Which hotel are staying in?

I stayed in the Riu Palace Peninsula in April and the snorkelling wasn't great. If you have the time go to Cozumel or Isla Mujeres it's far better over there.

Here are some photos/video from my trip last month http://goo.gl/XwJpNA diving was one of the best trips I done.

Snorkeling around Cancun isn't much to speak of. But, Puerto Morelos, Akumal, Cozumel all have great snorkeling if you're willing to venture south.

The closest point for snorkeling would be Isla Mujeres: http://visitroo.com/Isla_Mujeres
There you can snorkeling from the shore.

Ditto RAC