We had a delightful snorkel trip with Eco Adventures, located on the beach in Cabo Pulmo, next to the La Palapa restaurant.
This small family run business is a must stop in Cabo Pulmo. The brothers who run the business are very friendly, comfortable with non Spanish speakers and grew up in this delightful village.
We had the privilege of being in Cabo Pulmo for several days, and booked a trip on a day that turned out to be quite windy. While other operators were going out into less than ideal conditions, Juan convinced us to wait a few days till conditions settled down, placing our comfort and enjoyment ahead of that days profit!
You will pass other snorkeling shops, some of which specialize in diving as well, and I am sure that they provide a great trip, but Eco Adventures should be your choice.
Whales, snorkeling with Sea Lions, and lots of fish on the various parts of the reef are your reward.
BTW, Cabo Pulmo is a laid back kind of place, where you are pretty much left alone by folks trying to solicit your business. The one exception to this was an employee of a competing business who followed us down the street, telling us to cancel with Eco, so he could take us out for "less" . It was a jarring interjection of the aggressive sales techniques you run into in Cabo San Lucas and other tourist areas. It was totally out of place in Cabo Pulmo and guaranteed that that shop would not receive our business regardless of price. Our negative impression of this individual was further reinforced since it was on the windy day mentioned above that he wanted to take us.