I had really wanted to learn how to scuba dive on my trip to Jamaica, but we just never got around to making all the arrangements. But I did get to see some amazing sea life snorkeling the shallows off the resort's shoreline. Brightly colored fish that weren't so small darted by, and occasionally lingered so that I could get a closer look. I saw some angel fish and many of those long nosed yellow fish.
I was somewhat frustrated with all the slimy vegetation that was growing up from the ocean floor, which kept brushing against me and blocking my vision. But I later realized that the weeds probably encouraged the presence of these large exotic fish, who needed to hide from preying animals.
The snorkeling equipment provided is bare bones, and it might be worth bringing along your own equipment. Also, be careful not to stay out too long less you roast your backside like I did from less than a half hour of snorkeling without water-based sunscreen.