First time for swimming with the dolphins. Took my three kids (ages 9,8,6) as well as wife and my parents. It was a short boat ride to the area where the dolphins were hanging out. I lost count the number of dolphins we saw. I was unable to swim, due to a recent operation - so I hung out on the boat with China (captain). We stayed at the initial spot for about an hour (a long time for snorkeling) before moving to another location to find manta rays (which he did find). The group snorkeled for about 30 minutes before the boat took everyone back to the dolphins and swimming there for another 30 minutes or so. Everyone thought the swim was great. Dolphins everywhere, swimming behind, underneath and beside them. Was bummed I was unable to participate. Will definitely have to do this the next time we visit.
Of note: kids do wear life vests. There are noodles for them to use as well (which makes it easier for the adult to pull them about in the water). Waves did not seem too large, made the swim easy.