We spent a day at Cozumels Chankanaab Marine Park 4 years ago as part of a Carnival cruise
we walked out along the pier to catch the dolphin swim and after watching and speaking with the participates immediately tried to sign up, but unfortunately were told that they sell out weeks ahead
yes you do swim with the dolphins (checkout the link to their site see post above) and it looked like an experience of a lifetime (if youve swam with the stingrays in the caymans multiply times 100)
.definitely on my to do list
.go for it!!!! (Also, the day that we spent swimming at the beach directly to the right of the dolphin area was fantastic
.standing in 4 feet of the clearest water youve ever seen with the tropical fish swimming right between your legs was something my children still enjoy recalling years later)