Ylang Ylang booked our tour to Isla Tortuga with Zuma Tours and we couldn't have been happier. We had 19 people in our group so we had a boat all to ourselves. The guides were very friendly and were quick to slow the boat to a stop so that we could witness dolphins, whales and a passing shark..
Thankfully the shark viewing was on our way home, and not on our way to the snorkeling point! The guides were very helpful in assisting our 6 year old who was afraid of wearing a mask - go figure. The area they took us to snorkel was nice. We viewed starfish, pufferfish, numerous coral reef fish - even Nemo and Dory, sea cucumbers, dog fish, sea urchins and anemones. The guides constantly surfaced with objects to show everyone and alerted everyone to the sting ray!
If you have younger kids you may want to bring or purchase your own snorkeling gear. The mask was way too big for our 6 year old and filled with water. Basically, he couldn't use it. The mask I had was used so many time it leaked as well. They are cheap enough in town and I think comparable to the rental price.
The Island of Isla Tortuga has a gift shop (so much for the uninhabited island as per brochure LOL) and porta johns that cost one dollar to use. You can also rent lounge chairs.
The BBQ fish was awesome that the guides prepared for us for lunch. The guides cut up fruit and even hacked up coconut for us. Pura Vida!!!!
Since the boat was our group only we pretty much got to do what we wanted. Some of us stayed on the island and mixed drinks, others swam in the beach, others went on giant conch shell searches (and found them!!!), and other had the boat take them back to the snorkeling point.
We had an ultra-fabulous time and I highly recommend this tour to groups of people. Bring sun block...... and make sure you use plenty of it!