Reservations needed for Eco tour w/Vallarta Adventures?

Would like to spend one day with dolphins/whales/snorkeling. Should we make reservations? Also, any other tour company to consider?

David, thanks for your reply. Sounds like you might prefer the catamaran? Do you know how many people they usually take?

If memory serves, I think that Geronimo may take around 15-20 people and crew of 4. After snorlleing at Marianas Islands there is an open bar and good lunch buffet, then they stop at a secluded beach on the south side of the bay for a couple hours just relaxing. Vallarta Adventures does pretty much the same but with a lot more people and no sailing.