Love Cozumel! I've only been twice, and I'm looking forward to many more visits.
The first trip I went to Chichen Itza and it was a looooooooong bus ride, but the scenery was beautiful. I can't remember our guide's name, but he spiced up the trip with some hashtag-fun-facts until we actually got there. Worth the experience, but idk if I'll do it again.
On the second trip, I did the Frontier Mayan Horseback Riding - you ride through a forest and get to see some Mayan ruins and artifacts, including a ball court, up close. The guide, Carlos, is pretty funny and very knowledgeable. When you get saddled up, a boy who works for the ranch will take your picture which you can then buy after your ride. You then stop a nice little stretch of beach with some vendors, a couple of guys with critters (iguana and I think the other one was a macaw) you can pose with for donations, and a bar - I spent about $18 on a quesadilla (a little on the small side, but whatever) and margarita, both were delicious - and then you head back to the ship. 10/10 will def go again.