We didn't book formal excursions in either and found plenty to do.
We loved both.
In Grand Cayman..we did grab a cab at the dispatch center and take the two hour island taxi tour. Takes you to turtle farm, hell, etc. Allows you time to get our and enjoy each place. Turtle farm has a great gift shop which is the perfect place to get postcards/stamps and get them ready to mail. You can drop them in the mailbox right outside the store. We were back to the center of town by lunch time, although the driver did offer to drop anyone at the beach who wanted to go. We checked out two micro-breweries I saw on the drive back in. They are on ocean side, in walking distance. Both have beautiful decks overlooking the water. The food is excellent at both, the beers are great also.
(Rackhams and Big Bamboo) While enjoying our beers/food we got a chance to visit with the locals..it was wonderful. We checked out the Hard Rock Cafe, took pics with all the pirates positioned around. Did some shopping. The day goes by quickly and we had a blast.
In Cozumel we took the advice of a previous cruiser from this board and grabbed a cab right away in the morning and headed to Mr. Sanchos Beach area. They said the food was wonderful, and great guacomole dip. They were correct. We enjoyed the beach area and the lunch was fantastic. We spent about 3 hours or so and then grabbed a cab back to town to start shopping and looking around. We had the taxi driver drop us in front of the forum shops..far end from the dock, so we could work our way back. We went upstairs to check out the humidor (cigars for hubby) and to have mojitos at the bar. The manager was in so we visited with her and the bartenders for a bit. It was excellent.
Downstairs is one of the recommended jewelry shops..also where you pick up for free diamond and tanzanite earrings. I had completely forgot about the coupons for the free earrings..as we were leaving the store, a young man come up to me and said..did you get your free earrings..I said..oh, I forgot about those..I don't have the coupons from the ship anyway. He said..thats ok and handed me the 4 pairs of diamond earrings and however many tanzanite. I thanked him, we were about to leave when I noticed something shiny and pink..lol..so I ended up making a purchase. We headed another block or so away from the dock to Sedano's grocery store (on the recommendation of the manager from upstairs) to purchase Tequila and vanilla. We also got cool drinks. Nice small grocery store. Then started working our way back. We love the Cinco Soles (no haggling store) great prices adn the variety..you can't even imagine. We did most of our shopping in there. Kept working our way back..it was late after noon..we decided to take all our packages back to the ship..freshen up and then come back out for dinner. We finished looking around the courtyard shopping area, the food smelled so wonderful. The churros from the street vendor are very good. Then we headed to Carlos and Charlies for dinner. Great place, excellent food, live music. Open in the front..oceanview...right across from the dock. You can see the magic all lit up..just beautiful. We stayed until it was time to get back on the ship and leave port. A perfect day!