Snorkeling off the beach at Occidental Grand is only fair. There are a few starfish and a couple of schools of fish who make their home there; the turtle and rays were elusive during our few snorkeling periods, so we opted to pay for a four-hour snorkeling cruise with two other couples.
At Dive Palancar, we "negotiated" a private glass bottom boat for our trip at $45 per person. We went from 9am to 1pm with our guide Alfredo, nicknamed Parito (or Pirate!). He's been a dive master for 40 years and really knows the reefs. He brought along a cooler of soda, water, and beer for the trip, and a snack of chips.
The great advantage of having your own group is that you can decide how long to snorkel at each spot and the glass bottom boat lets you see even during the trip from one spot to the next. A canopied top provides some relief from the sun.
On the way to Columbia Shallows -- our favorite reef -- we saw four rays, a turtle, and the usual coral and schools of blue tangs. There's no effort to this snorkeling. A drift moves you along the reef and tons of inquisitive fish were kissing our masks and swimming along with us. We followed a turtle for a while and saw a barracuda in the distance.
"El Cedral" has towering coral heads and "El Cielo" is mostly sandy, but has so many starfish of all sizes -- we saw well over 100 of them. Between the snorkeling stops, Parito tried to find sharks for us, but it didn't work out (though I swear that I saw one). We did see a wahoo.
On the way back, we had the pleasure of being accompanied by two show-off dolphins. It was the best snorkeling experience ever -- hope it's as good for you.