please read all the dolphin literature carefully. Last winter we were on a HAL cruise and did the dolphin swim. It was very disappointing compared to stories and pictures we've seen of friends doing it.
Ours was in Jamaica and we were just floating in life jackets while dolphins swam by us. we were allowed to touch them once by holding out our hands and letting the dolphin swim by.
I've had friends do it were they actually get pulled around in the water so please ask lots of questions before booking.
This advice is good for anything that you do. It is also why boards like this are so important. There have always been three tiers of Dolphin swim. It is true that the lest costly is barely getting into the water.