What do you recommend for 11, 6, 4 year olds?

We are headed to Grand Cayman and we have kind of a big age gap between our kids. We usually go to the beach in the gulf for a week, so we are perfectly ok with spending the day at the beach. However, because it is our kid's first cruise, we want it to be a nice clear beach that isn't over crowded.

Or if there is a particular kid friendly excursion that would appeal to all three kids, please suggest it. It would need to involve swimming/water, not walking around touring anything.

Thanks!

While we were in Grand Cayman we did the turtle farm. We did not book through the boat just grab a local bus ( a white mini van just stand by side of road and the will stop, has a green dot sticker on them). It was $2.50 each way for all of us. We purchased the whole farm pass and it was very nice. As we entered we went and changed while the cruise groups were led through a tour and talk about the turtles and then had the place to ourselves. We did a short walk through and held the turtles then went on to the pool. There is a water slide, a water fall and a pool to enjoy. We then went to the lagoon and snorkeling with the turtles. The water does get rather deep in areas towards the middle of the lagoon but with a life jacket my son had no problem. It was a great day with very little walking but a lot to do. The changing areas were clean and there were covered beach chairs to get out of the sun if need be.

Take the shuttle to SeaGrape Beach and as you exit the shuttle walk towards the playground. This family area does not get crowded, there is a restroom, chairs, umbrellas and limited food and drink.

Just up the beach is Calico Jacks where there is a full food menu along with alcohol. At CJ's you can parasail, jetski or take a banana boat ride if the adults are interested.