Hi,
My sister and I swam with the dolphins in Chankanaab last October, we booked this tour through Princess as we were sailing on the Grand. It cost $149.00 per person and to me, was well worth every penny, it was definitely an experience of a lifetime and I would do it again in a heartbeat. The cost included the taxi ride to and from the ship and the dolphin swim. You had to pay an additional $10 fee for admission to Chankanaab Park.
The link that hstrybuf posted is the correct website. I think they call it the royal swim and it costs $119.00 per person. This excursion books up very quickly as they only allow a small number of people, I think it's about 10, but I'm not positive. This excursion was sold out and wait listed even before the Grand sailed, so if you want to swim with the
dolphins book it as soon as you can.
Have a wonderful time!
Rose