We had this tour booked in Cozumel, but ended up cancelling at the last minute to go to Xcaret instead. We considered it after an identical trip in Lahaina, Maui, that we enjoyed a lot. Surprisingly, the best part of that was not the submarine ride itself, but rather the beautiful trip in the tender out to the pick up point. Seeing the submarine appear and getting into it was also exciting. After visiting Cozumel, I was relieved that we cancelled since the water was rough that day and the tender would have been a nightmare. The ferry ride to Playa del Carmen was bad enough. If it wasn't for that, I would have considered going when we stop by Cozumel again in the fall. Instead, we may just go shopping on our own in Playa del Carmen. We went back there to spend more time after the cruise and enjoyed it a lot. There's a very nice, brand new shopping district right at the point where you get dropped off the ferry.