Ahoy, Caroline!
I'm so glad you navigated your way to the Disney Parks Moms Panel to ask your question. I have a dolphin-loving child as well.
Since you said you are embarking on September 19, it looks to me like you are on the Disney Fantasy Western Caribbean cruise. If that is the case, you can swim with dolphins in Cozumel or Grand Cayman. Our family has experienced the
"Dolphin Push Pull and Swim" port adventure in Cozumel. My daughters loved it! We also have friends who have participated in the
"Dolphin Encounter and Turtle Farm" port adventure in Grand Cayman, and they highly recommend it, too!
While there is not a place to swim with dolphins at Castaway Cay, you can visit some of their ocean-dwelling friends, the stingrays, at
Castaway Rays Stingray Adventure. Our family loved the interaction with the stingrays, and we even got to feed them. Afterwards, we were able to swim in the stingray lagoon for about 30 minutes and took some great photos.
No matter your choice, I'm sure your six year old will have a splashing good time on your Disney cruise! If you have further planning questions, please ask away.
Happy Cruising, Tracy V.