While researching what we wanted to do for the Western Caribbean Cruise, I found the descriptions that interested our family the most from the port adventures page and then went to
YouTube to look up video clips (Carnival actually had the most helpful clips of just the excursions). That helped us decide if we wanted to sign up for that excursion.
Based on what we wanted to do, it narrowed it down for us that dolphins would be on Grand Cayman day, along with the stingray excursion. DH and I had been to Stingray City before pre-kids, so we knew we wanted to take the kids there so they could experience it.
I've pasted in what we did at each port below (we were just on the 7-day Western in early April). My boys (9 & 12) really enjoyed all 3 excursions we booked, except if I could do it again, I would book the dolphins & Stingray City outside of
DCL.
In Cozumel, we did the Amazing Secret River (Rio Secreto). Because the caves are in Playa Del Carmen, there's a 30 minute ferry ride each way, and we made it back to the ship with 5 minutes to spare before boarding time. We got about 30 minutes free time in Playa Del Carmen after the caves and before the ferry ride back if you want to shop, but everyone in our group headed for the beach. The caves are amazing - there's 5 different routes, and it's a 90 minute guided tour in the underground caves. The route varies between walking on rocky terrain to wading in water that's ankle deep to 10ft deep and you need to float/swim through. We were accompanied by a guide as well as a photographer, as you're not allowed to bring any phones/cameras/etc. The USB package with all photos is $99. Our boys (9 and 12) deemed this their favorite excursion. Lunch is included.
In Grand Cayman we did the dolphin swim and Stingray City. Stingray City was crowded, and having been there before with a private vendor, I feel that if we were to go again, I would not book this excursion through Disney. There were too many people in our group for the stingrays and every family got one interaction with the stingray (more of a photo op that they try to upsell you - you hold the ray, kiss the ray, and then the guide moves on to the next family). We did not buy the stingray pictures. The dolphin experience is a lot better. We had a group of 9, so it was a manageable group. Pictures for the dolphins are $60 per person. Lunch was not included in this excursion, but there's a food stand at the dolphin place.
In Jamaica, we did the bobsledding and Dunn's River Falls. Dunn's River Falls is so fun - my boys had this as their second favorite activity. Our bus did the bobsledding first, lunch was provided at Mystic Mountain, and then we were taken to Dunn's River Falls. The climb up the waterfall was amazing, with a lot of different stops to slide down a small rock slide, or be completely submerged behind a small waterfall. There was a guide to help move the group along and a videographer that filmed clips as well as took still shots of the family. The DVD that they sell you at the end is $40 with all the video clips and stills. The quality is poor - fuzzy pictures, but we were glad we got the family pictures.