The highlight of course for me, is snorkeling Hol Chan and Shark Ray Alley. Here I get to see a large variety of fish. Just recently my Papa was standing on the deck, and one of the tour guides came up to him and said, "Is that your grandson?" "Yes", he said. "Well that kid knows how to swim and boy does he know his fish!" I laughed when I heard this.
So, if you are looking for something to do with your grandparents, something low impact and allows you to spend the day together, then I am suggesting, take your grandparents on the day sail to Caye Caulker. You'll get to snorkel Hol Chan, swim with sharks at Shark Ray Alley, and let the grownups drink the beer. Yes I'm talking real sharks, but not the kind that will eat you. Our guide even picked one up, turned him over and we got to pet his belly. He's called the "shark whisperer".
If you've ever touched a shark, their skin feels like a rough rubbery avocado. Nurse sharks are fairly gentle animals, so enjoy the time swimming with these big guys! There are not many places in the world, where you can say you "swam with the sharks!"