We will be in Cozumel from 10am till 7pm. Would we have enough time to rent a car and go to Chankanaab, do the dolphin swim, snorkel a little, then go to Paradise Beach? Would we be really rushing things?
Went to Chankanaab last April when we were in Playa del Carmen. Don't bother to snorkel there. The water is really rough and it is very rocky. Cozumel is known for fabulous scuba diving, not snorkeling. There were also a lot of jellyfish in the water. I was very diappointed in Chankanaab. As for distance from port to Chankanaab it only took us 10 minutes by taxi to get there. I would think that both excursions are doable in the amount of time you have especially if you don't snorkel.
I have snorkeled several spots in Cozumel and they were great. Jellies can be found in all waters at diffrent times, does not mean they will be there when you are. The waters around Cozumel have beautiful coral and marine life. Enjoy. Katie