We loved Seven Mile Beach in Grand Cayman. We took the public bus, which was very easy to find (look for the library, it's about 2 blocks from the entrance of the cruise port). $2.50 per person and there was a mix of tourists and locals on it.
We did not rent beach chairs, just sat on the sand. It was very crowded, but that did not spoil our experience as the water is so beautiful, warm, and clear, the sand is soft and not hot. There are bathrooms - I only went to the single stall restroom - I know there was another building but I didn't go there. We had a great day in Grand Cayman and would do it again without hesitation.