There is a thread right below you same topic. I liked climbing Dunnes river falls but many touts scammers there. River Rafting is nicer for me. Snorkel or Dive Sting Ray Alley my fav in Caymans. cruisecritic.com has ship tour reviews. Usually cheaper to oouple up and go in for a driver guide at the port for me usually.

Have fun!

DRF is worth it! Its a lot of fun but you have to do some climbing so you have to be in decent shape.

In GC the prime attraction is stingray city.

For us using private operators is almost always preferable. If you go to cruise critic and to the port boards you can ask for reputable operators. However usually in Caribbean there will be plenty of them on the dock. Personally I would search for one and prearrange it. No worries.

Personally, I would skip DRF unless you really want to climb it with tons of other people. For gorgeous waterfalls and less crowds go to Shaw Park Gardens and Coyoba Falls instead. Rafting down the Martha Brae is a good option also. We used A-Z Jamaica Planners to escort us to the attractions we wanted to see. I would definitly recommend either booking a cruise ship excursion or a company online before you cruise in Jamaica. People there can be quite aggressive and haggling at the pier is not a fun option.

Swimming with the Sting Rays in the main attraction in GC. You can also do an Island tour, go to the botantical gardens, shopping around Georgetown, semi submarine, or chill out on 7 Mile Beach.

We just returned last week from a Celebrity Millenium cruise to Falmouth and Gr. Cayman. We loved it! We booked our excursions through the ship. In Falmouth we picked an excursion to go to Montego Bay, the Irie Mon Beach Break. It was a short 30 min. ride there. We had a beach chair, a small (practically private) beach, yummy lunch, and drinks. The day was relaxing, safe, and fun. We were asked for tips while there from the drinks guys and the umbrella men (we paid an extra $5 per couple for the shade.)
In Gr. Cayman we did the Dolphin Encounter, Stingray City, and Tiki Beach. It was a lot to do in one day. We really enjoyed our day, except that we did not feel very welcome at Tiki Beach. (it is just a little slice of beach with a bar, next to another bar, next to another bar...)
Overall, it was fun,though.
**On the ship, do NOT miss the fantastic brunch on the last day at sea. Yummy and awesome!

Jamaica Cruise Excursions offers great excursions from Falmouth. http://jamaicacruiseexcursions.com We loved the beach break all inclusive!