We were thinking about booking the Playa Mia Beach break excursion in Cozumel. It show sthat it is 5 hours long. Do you have to stay for the entire 5 hours, or can you leave after say 3 hours or so and go shopping before returning to the ship?
There is certainly nothing they can do if you want to get in a taxi and leave. Some tours include the transportation costs, others don't. If you pay for a taxi on your own it will be about $15 per taxi (up to 4 people).
If you book the excursion thru the cruise line, they designate specific times for return trips to the pier. If you take a taxi back, that will add to the cost of your excursion and negate any "break" you might incur by booking the excursion. We went to Playa Mia on our own, walked to the taxi stand (prices are posted) from the ship and took a taxi back to the ship when we had our fill of water, sand, and liquor.