Welcome aboard, Kimberlee! The
Cozumel Ruins and Beach Tour is one of my favorite Port Adventures in Cozumel. We loved every bit of this adventure last year and I highly recommend it.
The adults will really enjoy learning about the history and culture as you step back in time at the ancient Mayan ruins. Even the kids learn quite a bit there! After that, a tour of the beautiful scenery around the entire island brings you to the Playa Mia Beach Resort where you can relax, sip a fruity drink and play in the surf and sand! It truly includes a little something for everyone! We had a really great guide on this adventure and learned so much from him as we traveled! I'm sure you'll find the same.
The reason you can't add your 10-month old child is that children ages 0-2 are free on this particular Port Adventure. Since you won't be paying for him, the reservation system doesn't allow you to add him. Simply arrive at the meeting location on the day of your adventure with him in tow and you'll be all set. He won't need a ticket.
I hope that helps, Kimberlee! Let me know what other questions you might have before you set sail! I'm happy to help!